‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,9005.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,30031
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,30031
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,0005
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
‡‡‡ Chapter 4 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 4
GAS PIPING INSTALLATIONS
SECTION 
FGC
401
GENERAL
401.1 Scope.
This chapter shall govern the design, installation, modification and maintenance of 
fuel
-
gas
piping sys-
tems. The 
scope covered by
this 
chapter includes
piping 
systems from the point of delivery to the connections with 
the appliances and includes the design, materials, components, fabrication, assembly, installation, testing, inspection, 
operation and maintenance of such piping systems.
401.1.1 
Meters and service
piping.
Service piping includes the fuel
-
gas piping up to the point of delivery. Meters 
and service piping shall comply with the requirements of Appendix 
E
. In addition,
service piping located within 
buildings shall be 
designed and
installed in accordance with the structural 
integrity, firestopping,
and fire protection 
provisions of the 
New York City
Building Code
.
401.1.2 
Meters
for 
gas consumption monitoring.
Approved
gas 
meters
shall be 
permitted to be installed for gas 
consumpti
on monitoring, energy measurement, verification and analysis. Gas meters shall be listed in accordance 
with ANSI B109.1, ANSI B109.2, or ANSI B109.3
and installed in accordance with the 
manufacturer’s instruc-
tions. A full size valve bypass shall be provide
d around gas meters for maintenance and repair.
401.2 Reserved.
401.3 Modifications to existing systems.
In modifying or adding to existing piping systems, sizes shall be maintained 
in accordance with this chapter.
401.4 Additional appliances.
Where an add
itional appliance is to be served, the existing piping shall be checked to 
determine if it has adequate capacity for all appliances served. If inadequate, the existing system shall be enlarged as 
required or separate piping of adequate capacity shall be pr
ovided.
401.5 Identification.
All
piping 
installed in new construction and all new piping installed in existing buildings, 
whether or not the piping is intended to be enclosed when construction is completed,
shall be identified by a yellow 
label marked “Gas” in black letters. 
Where the installation requires a gas 
test, such
labeling shall be completed prior 
to such test. Labels shall be provided in accordance with ASME A13.1 and the
marking shall be spaced at
intervals 
not exceeding 5 feet (1524 mm). The marking shall not be required on pipe located in the same room as the appliance 
served.
401.6 Interconnections.
Where two or more meters are installed on the same premises but supply separate consumers, 
the pi
ping systems shall not be interconnected on the outlet side of the meters.
401.7 Piping meter identification.
Piping from multiple meter installations shall be marked with an approved per-
manent identification by the installer so that the piping system supp
lied by each meter is readily identifiable. 
Such 
marking shall be in accordance with ASME A13.1.
401.8 Minimum sizes.
Pipe
utilized for the installation, extension and alteration of any piping system shall be sized 
to supply the full number of outlets for 
the intended purpose and shall be sized in accordance with Section 402.
401.9 Identification.
Each length of pipe and each pipe fitting, utilized in a fuel gas system, shall bear the identifica-
tion of the manufacturer.
401.10 Third
-
party testing and certif
ication.
Piping, tubing and fittings shall comply with the applicable referenced 
standards, specifications and performance criteria of this code and shall be identified in accordance with Section 401.9. 
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
Piping, tubing and fittings shall either be tested by
an approved third
-
party testing agency or certified by an approved 
third
-
party
certification agency.
SECTION FGC 402
PIPE SIZING
402.1 General considerations.
Piping systems shall be of such size and so installed as to provide a supply of gas 
sufficient t
o meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply 
pressure required by the appliance.
402.2 Maximum gas demand.
The 
volumetric flow rate
of gas to be provided shall be the 
sum
of the maximum input 
of the a
ppliances
served.
The total connected hourly load shall be used as the basis for pipe sizing, 
assuming
that all 
appliances
could be 
operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted 
to b
e based on such loads.
The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 
feet (610 m) in elevation.
402.3 Sizing.
Gas piping shall be sized in accordance with one of the following:
1.
Pipe s
izing tables or sizing equations in accordance with Section 402.4.
2.
The sizing tables included in a listed piping system’s manufacturer’s 
instructions
. 
3.
Other approved engineering methods.
4.
Individual outlets to gas ranges shall not be less than   
3
/
4
inches (
19.1
mm) NPS.
402.4 Sizing tables and equations.
Where Tables 402.4(1) through 
402.4(
7) 
are used to size piping or tubing, the 
pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
Where Equations 4
-
1 and 4
-
2 are used to size piping or tubing, the pipe or tubing shall have smooth inside walls 
and the pipe length shall be determined in accordance with Section 402.4.1, 402.4.2 or 402.4.3.
1. Low
-
pressure gas equation (Less than 
1
1
/
2
pounds per square inch (psi) (10.3 kPa
))
: 
D =  
Q
0
.
381
19
.
17
�
∆H
C
r
 ×
L
�
0
.
206
(Equation 4
-
1)
2. High
-
pressure gas equation (1
1
/
2
psi (10.3 kPa) and above
):
D =  
Q
0
.
381
18
.
93
�
�P
1
2
−
P
2
2
�
 ×
Y
C
r
 ×
L
�
0
.
206
(Equation 4
-
2)
where:
D 
= 
Inside diameter of pipe, inches (mm).
Q 
= 
Input rate appliance(s), cubic feet per hour at 60°F 
(
15.6
°C) and 30
-
inch mercury
column.
P
1
  = 
Upstream 
pressure, psia (
P
1
+ 14.7
).
P
2
  = 
Downstream pressure, psia (
P
2
+ 14.7
).
L 
= 
Equivalent length of pipe,
feet.
∆
H
 = 
Pressure drop, inch water column (27.7 inch water col
umn = 1 psi).
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
TABLE 402.4
C
r
AND 
Y  
VALUES FOR NATURAL GAS
AT STANDARD 
CONDITIONS
GAS
EQUATION FACTORS
C
r
Y
Natural gas
0.6094
0.9992
For SI: 1 cubic foot = 0.028 m
3
, 1 foot = 305 mm, 
1
-
inch water column = 0.2488 kPa, 
1 pound per square inch = 6.895 kPa,
1 British thermal 
unit per hour = 0.293 W.
402.4.1 
Longest length method.
The pipe size of each section of gas piping shall be determined using the 
longest length of piping from the point of delivery to the most remote outlet and the load of the section.
402.4.2 Branch length method.
Pipe shall be sized as
follows:
1.
Pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be 
determined using the longest run of piping and the load of the section.
2.
The pipe size of each section of branch piping not 
previously sized shall be determined using the length of 
piping from the point of delivery to the most remote outlet in each branch and the load of the section.
402.4.3 Hybrid pressure.
The pipe size for each section of higher pressure gas piping shall be 
determined using 
the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size 
from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to 
the most
remote outlet served by the regulator.
TABLE 402.4(1)
SCHEDULE 40 METALLIC PIPE
Gas 
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.3 in. w. c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
31,700
51,300
105,000
191,000
303,000
20
90
188
353
726
1,090
2,090
3,340
5,900
12,000
21,800
35,300
72,400
132,000
208,000
30
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
40
62
129
243
499
747
1,440
2,290
4,050
8,270
15,000
24,200
49,800
90,400
143,000
50
55
114
215
442
662
1,280
2,030
3,590
7,330
13,300
21,500
44,100
80,100
127,000
60
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
70
46
95
179
368
552
1,060
1,690
3,000
6,110
11,100
17,900
36,800
66,800
106,000
80
42
89
167
343
514
989
1,580
2,790
5,680
10,300
16,700
34,200
62,100
98,400
90
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
100
38
79
148
304
455
877
1,400
2,470
5,040
9,110
14,800
30,300
55,100
87,200
125
33
70
131
269
403
777
1,240
2,190
4,460
8,080
13,100
26,900
48,800
77,300
150
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
175
28
58
109
224
336
648
1,030
1,820
3,720
6,730
10,900
22,400
40,700
64,400
200
26
54
102
209
313
602
960
1,700
3,460
6,260
10,100
20,800
37,900
59,900
250
23
48
90
185
277
534
851
1,500
3,070
5,550
8,990
18,500
33,500
53,100
300
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
350
19
40
75
154
231
445
709
1,250
2,560
4,630
7,490
15,400
28,000
44,300
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
400
18
37
70
143
215
414
660
1,170
2,380
4,310
6,970
14,300
26,000
41,200
450
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
500
16
33
62
127
191
367
585
1,030
2,110
3,820
6,180
12,700
23,100
36,500
550
15
31
59
121
181
349
556
982
2,000
3,620
5,870
12,100
21,900
34,700
600
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
650
14
29
54
110
165
318
508
897
1,830
3,310
5,360
11,000
20,000
31,700
700
13
27
52
106
159
306
488
862
1,760
3,180
5,150
10,600
19,200
30,400
750
13
26
50
102
153
295
470
830
1,690
3,060
4,960
10,200
18,500
29,300
800
12
26
48
99
148
285
454
802
1,640
2,960
4,790
9,840
17,900
28,300
850
12
25
46
95
143
275
439
776
1,580
2,860
4,640
9,530
17,300
27,400
900
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
950
11
23
44
90
135
259
413
731
1,490
2,700
4,370
8,970
16,300
25,800
1,000
11
23
43
87
131
252
402
711
1,450
2,620
4,250
8,720
15,800
25,100
1,100
10
21
40
83
124
240
382
675
1,380
2,490
4,030
8,290
15,100
23,800
1,200
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
1,300
NA
20
37
76
114
219
349
617
1,260
2,280
3,680
7,570
13,700
21,800
1,400
NA
19
35
73
109
210
335
592
1,210
2,190
3,540
7,270
13,200
20,900
1,500
NA
18
34
70
105
203
323
571
1,160
2,110
3,410
7,010
12,700
20,100
1,600
NA
18
33
68
102
196
312
551
1,120
2,030
3,290
6,770
12,300
19,500
1,700
NA
17
32
66
98
189
302
533
1,090
1,970
3,190
6,550
11,900
18,800
1,800
NA
16
31
64
95
184
293
517
1,050
1,910
3,090
6,350
11,500
18,300
1,900
NA
16
30
62
93
178
284
502
1,020
1,850
3,000
6,170
11,200
17,700
2,000
NA
16
29
60
90
173
276
488
1,000
1,800
2,920
6,000
10,900
17,200
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 
6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three 
significant digits.
TABLE 402.4(2) 
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2 psi
Pressure Drop
0.5 
in
w.c.
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
5
6
8
10
12
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
5.047
6.065
7.981
10.020
11.938
Length 
(ft)
Capacity in Cubic Feet of Gas Per Hour
10
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
41,800
67,600
139,000
252,000
399,000
20
118
247
466
957
1,430
2,760
4,400
7,780
15,900
28,700
46,500
95,500
173,000
275,000
30
95
199
374
768
1,150
2,220
3,530
6,250
12,700
23,000
37,300
76,700
139,000
220,000
40
81
170
320
657
985
1,900
3,020
5,350
10,900
19,700
31,900
65,600
119,000
189,000
50
72
151
284
583
873
1,680
2,680
4,740
9,660
17,500
28,300
58,200
106,000
167,000
60
65
137
257
528
791
1,520
2,430
4,290
8,760
15,800
25,600
52,700
95,700
152,000
70
60
126
237
486
728
1,400
2,230
3,950
8,050
14,600
23,600
48,500
88,100
139,000
80
56
117
220
452
677
1,300
2,080
3,670
7,490
13,600
22,000
45,100
81,900
130,000
90
52
110
207
424
635
1,220
1,950
3,450
7,030
12,700
20,600
42,300
76,900
122,000
100
50
104
195
400
600
1,160
1,840
3,260
6,640
12,000
19,500
40,000
72,600
115,000
125
44
92
173
355
532
1,020
1,630
2,890
5,890
10,600
17,200
35,400
64,300
102,000
150
40
83
157
322
482
928
1,480
2,610
5,330
9,650
15,600
32,100
58,300
92,300
175
37
77
144
296
443
854
1,360
2,410
4,910
8,880
14,400
29,500
53,600
84,900
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
200
34
71
134
275
412
794
1,270
2,240
4,560
8,260
13,400
27,500
49,900
79,000
250
30
63
119
244
366
704
1,120
1,980
4,050
7,320
11,900
24,300
44,200
70,000
300
27
57
108
221
331
638
1,020
1,800
3,670
6,630
10,700
22,100
40,100
63,400
350
25
53
99
203
305
587
935
1,650
3,370
6,100
9,880
20,300
36,900
58,400
400
23
49
92
189
283
546
870
1,540
3,140
5,680
9,190
18,900
34,300
54,300
450
22
46
86
177
266
512
816
1,440
2,940
5,330
8,620
17,700
32,200
50,900
500
21
43
82
168
251
484
771
1,360
2,780
5,030
8,150
16,700
30,400
48,100
550
20
41
78
159
239
459
732
1,290
2,640
4,780
7,740
15,900
28,900
45,700
600
19
39
74
152
228
438
699
1,240
2,520
4,560
7,380
15,200
27,500
43,600
650
18
38
71
145
218
420
669
1,180
2,410
4,360
7,070
14,500
26,400
41,800
700
17
36
68
140
209
403
643
1,140
2,320
4,190
6,790
14,000
25,300
40,100
750
17
35
66
135
202
389
619
1,090
2,230
4,040
6,540
13,400
24,400
38,600
800
16
34
63
130
195
375
598
1,060
2,160
3,900
6,320
13,000
23,600
37,300
850
16
33
61
126
189
363
579
1,020
2,090
3,780
6,110
12,600
22,800
36,100
900
15
32
59
122
183
352
561
992
2,020
3,660
5,930
12,200
22,100
35,000
950
15
31
58
118
178
342
545
963
1,960
3,550
5,760
11,800
21,500
34,000
1,000
14
30
56
115
173
333
530
937
1,910
3,460
5,600
11,500
20,900
33,100
1,100
14
28
53
109
164
316
503
890
1,810
3,280
5,320
10,900
19,800
31,400
1,200
13
27
51
104
156
301
480
849
1,730
3,130
5,070
10,400
18,900
30,000
1,300
12
26
49
100
150
289
460
813
1,660
3,000
4,860
9,980
18,100
28,700
1,400
12
25
47
96
144
277
442
781
1,590
2,880
4,670
9,590
17,400
27,600
1,500
11
24
45
93
139
267
426
752
1,530
2,780
4,500
9,240
16,800
26,600
1,600
11
23
44
89
134
258
411
727
1,480
2,680
4,340
8,920
16,200
25,600
1,700
11
22
42
86
130
250
398
703
1,430
2,590
4,200
8,630
15,700
24,800
1,800
10
22
41
84
126
242
386
682
1,390
2,520
4,070
8,370
15,200
24,100
1,900
10
21
40
81
122
235
375
662
1,350
2,440
3,960
8,130
14,800
23,400
2,000
NA
20
39
79
119
229
364
644
1,310
2,380
3,850
7,910
14,400
22,700
For SI: 1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.293 1 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Notes:
1. NA means a flow of less than 10 cfh.
2. All table entries have been rounded to three significant digits.
TABLE 402.4(3)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
3.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply 
pressure of 8.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
454
949
1,790
3,670
5,500
10,600
16,900
29,800
60,800
20
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
30
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
40
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
50
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
60
172
360
678
1,390
2,090
4,020
6,400
11,300
23,100
70
158
331
624
1,280
1,920
3,700
5,890
10,400
21,200
80
147
308
580
1,190
1,790
3,440
5,480
9.690
19,800
90
138
289
544
1,120
1,680
3,230
5,140
9,090
18,500
GAS PIPING INSTALLATIONS
100
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
125
116
242
456
936
1,400
2,700
4,300
7,610
15,500
150
105
219
413
848
1,270
2,450
3,900
6,890
14,100
175
96
202
380
780
1,170
2,250
3,590
6,340
12,900
200
90
188
353
726
1,090
2,090
3,340
5,900
12,000
250
80
166
313
643
964
1,860
2,960
5,230
10,700
300
72
151
284
583
873
1,680
2,680
4,740
9,700
350
66
139
261
536
803
1,550
2,470
4,360
8,900
400
62
129
243
499
747
1,440
2,290
4,060
8,300
450
58
121
228
468
701
1.350
2,150
3,800
7,800
500
55
114
215
442
662
1,280
2,030
3,590
7,300
550
52
109
204
420
629
1,210
1,930
3,410
7,000
600
50
104
195
400
600
1,160
1,840
3,260
6,640
650
47
99
187
384
575
1,110
1,760
3,120
6,360
700
46
95
179
368
552
1,060
1,700
3,000
6,110
750
44
92
173
355
532
1,020
1,630
2,890
5,890
800
42
89
167
343
514
989
1,580
2,790
5,680
850
41
86
162
332
497
957
1,530
2,700
5,500
900
40
83
157
322
482
928
1,480
2,620
5,330
950
39
81
152
312
468
901
1,440
2,540
5,180
1,000
38
79
148
304
455
877
1,400
2,470
5,040
1,100
36
75
141
289
432
833
1,330
2,350
4,780
1,200
34
71
134
275
412
794
1,270
2,240
4,560
1,300
33
68
128
264
395
761
1,210
2,140
4,370
1,400
31
65
123
253
379
731
1,170
2,060
4,200
1,500
30
63
119
244
366
704
1,120
1,980
4,050
1,600
29
61
115
236
353
680
1,080
1,920
3,910
1,700
28
59
111
228
342
658
1,050
1,850
3,780
1,800
27
57
108
221
331
638
1,020
1,800
3,670
1,900
27
56
105
215
322
619
987
1,750
3,560
2,000
26
54
102
209
313
602
960
1,700
3,460
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square 
inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 402.4(4)
SCHEDULE 40
METALLIC PIPE 
Gas
Natural
Inlet Pressure
Less than 2.0 psi
Pressure Drop
6.0 in. w.c.
Specific Gravity
0.60
INTENDED USE: Initial supply pressure of 11.0 inches w.c. or greater
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
660
1,380
2,600
5,340
8,000
15,400
24,600
43,400
88,500
20
454
949
1,790
3,670
5,500
10.600
16,900
29,900
60,800
30
364
762
1,440
2,950
4,420
8.500
13,600
24,000
48,900
40
312
652
1,230
2,520
3,780
7,280
11,600
20,500
41,800
50
276
578
1,090
2,240
3,350
6,450
10,300
18,200
37,100
60
250
524
986
2,030
3,030
5,840
9,310
16,500
33,600
70
230
482
907
1,860
2,790
5,380
8,570
15,100
30,900
GAS PIPING INSTALLATIONS
80
214
448
844
1,730
2,600
5,000
7,970
14,100
28,700
90
201
420
792
1,630
2,440
4,690
7,480
13,200
27,000
100
190
397
748
1,540
2,300
4,430
7,070
12,500
25,500
125
168
352
663
1,360
2,040
3,930
6,260
11,100
22,600
150
153
319
601
1,230
1,850
3,560
5,670
10,000
20,500
175
140
293
553
1,140
1,700
3,280
5,220
9,230
18,800
200
131
273
514
1,060
1,580
3,050
4,860
8,580
17,500
250
116
242
456
936
1,400
2,700
4,300
7,610
15,500
300
105
219
413
848
1,270
2,450
3,900
6,890
14,100
350
96
202
380
780
1,170
2,250
3,590
6,340
12,900
400
90
188
353
726
1,090
2,090
3,340
5,900
12,000
450
84
176
332
681
1,020
1,970
3,130
5,540
11,300
500
80
166
313
643
964
1,860
2,960
5,230
10,700
550
76
158
297
611
915
1,760
2,810
4,970
10,100
600
72
151
284
583
873
1,680
2,680
4,740
9,660
650
69
144
272
558
836
1,610
2,570
4,540
9,250
700
66
139
261
536
803
1,550
2,470
4,360
8.890
750
64
134
252
516
774
1,490
2,380
4,200
8,560
800
62
129
243
499
747
1,440
2,290
4,060
8,270
850
60
125
235
483
723
1,390
2,220
3,920
8,000
900
58
121
228
468
701
1,350
2,150
3,800
7,760
950
56
118
221
454
681
1,310
2,090
3,700
7,540
1,000
55
114
215
442
662
1,280
2,030
3,590
7,330
1,100
52
109
204
420
629
1,210
1,930
3,410
6,960
1,200
50
104
195
400
600
1,160
1,840
3,260
6,640
1,300
47
99
187
384
575
1,100
1,760
3,120
6,360
1,400
46
95
179
368
552
1,060
1,700
3,000
6,110
1,500
44
92
173
355
532
1,020
1,630
2,890
5,890
1,600
42
89
167
343
514
989
1,580
2,790
5,680
1,700
41
86
162
332
497
957
1,530
2,700
5,500
1,800
40
83
157
322
482
928
1,480
2,620
5,330
1,900
39
81
152
312
468
901
1,440
2,540
5,180
2,000
38
79
148
304
455
877
1,400
2,470
5,040
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch 
water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.
01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(5)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
2.0 psi
Pressure Drop
1.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
1,510
3,040
5,560
11,400
17,100
32,900
52,500
92,800
189,000
20
1,070
2,150
3,930
8,070
12,100
23,300
37,100
65,600
134,000
30
869
1,760
3,210
6,590
9,880
19,000
30,300
53,600
109,000
40
753
1,520
2,780
5,710
8,550
16,500
26,300
46,400
94,700
50
673
1,360
2,490
5,110
7,650
14,700
23,500
41,500
84,700
60
615
1,240
2,270
4,660
6,980
13,500
21,400
37,900
77,300
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
70
569
1,150
2,100
4,320
6,470
12,500
19,900
35,100
71,600
80
532
1,080
1,970
4,040
6,050
11,700
18,600
32,800
67,000
90
502
1,010
1,850
3,810
5,700
11,000
17,500
30,900
63,100
100
462
934
1,710
3,510
5,260
10,100
16,100
28,500
58,200
125
414
836
1,530
3,140
4,700
9,060
14,400
25,500
52,100
150
372
751
1,370
2,820
4,220
8,130
13,000
22,900
46,700
175
344
695
1,270
2,601
3,910
7,530
12,000
21,200
43,300
200
318
642
1,170
2,410
3,610
6,960
11,100
19,600
40,000
250
279
583
1,040
2,140
3,210
6,180
9,850
17,400
35,500
300
253
528
945
1,940
2,910
5,600
8,920
15,800
32,200
350
232
486
869
1,790
2,670
5,150
8,210
14,500
29,600
400
216
452
809
1,660
2,490
4,790
7,640
13,500
27,500
450
203
424
759
1,560
2,330
4,500
7,170
12,700
25,800
500
192
401
717
1,470
2,210
4,250
6,770
12,000
24,400
550
182
381
681
1,400
2,090
4,030
6,430
11,400
23,200
600
174
363
650
1,330
2,000
3,850
6,130
10,800
22,100
650
166
348
622
1,280
1,910
3,680
5,870
10,400
21,200
700
160
334
598
1,230
1,840
3,540
5,640
9,970
20,300
750
154
322
576
1,180
1,770
3,410
5,440
9,610
19,600
800
149
311
556
1,140
1,710
3,290
5,250
9,280
18,900
850
144
301
538
1,100
1,650
3,190
5,080
8,980
18,300
900
139
292
522
1,070
1,600
3,090
4,930
8,710
17,800
950
135
283
507
1,040
1,560
3,000
4,780
8,460
17,200
1,000
132
275
493
1,010
1,520
2,920
4,650
8,220
16,800
1,100
125
262
468
960
1,440
2,770
4,420
7,810
15,900
1,200
119
250
446
917
1,370
2,640
4,220
7,450
15,200
1,300
114
239
427
878
1,320
2,530
4,040
7,140
14,600
1,400
110
230
411
843
1,260
2,430
3,880
6,860
14,000
1,500
106
221
396
812
1,220
2,340
3,740
6,600
13,500
1,600
102
214
382
784
1,180
2,260
3,610
6,380
13,000
1,700
99
207
370
759
1,140
2,190
3,490
6,170
12,600
1,800
96
200
358
736
1,100
2,120
3,390
5,980
12,200
1,900
93
195
348
715
1,070
2,060
3,290
5,810
11,900
2,000
91
189
339
695
1,040
2,010
3,200
5,650
11,500
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 
0.01745 rad.
Note:
All table entries have been rounded to three significant digits.
TABLE 
402.4(6)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
3.0 psi
Pressure Drop
2.0 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
2,350
4,920
9,270
19,000
28,500
54,900
87,500
155,000
316,000
20
1,620
3,380
6,370
13,100
19,600
37,700
60,100
106,000
217,000
30
1,300
2,720
5,110
10,500
15,700
30,300
48,300
85,400
174,000
40
1,110
2,320
4,380
8,990
13,500
25,900
41,300
73,100
149,000
50
985
2,060
3,880
7,970
11,900
23,000
36,600
64,800
132,000
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
60
892
1,870
3,520
7,220
10,800
20,800
33,200
58,700
120,000
70
821
1,720
3,230
6,640
9,950
19,200
30,500
54,000
110,000
80
764
1,600
3,010
6,180
9,260
17,800
28,400
50,200
102,000
90
717
1,500
2,820
5,800
8,680
16,700
26,700
47,100
96,100
100
677
1,420
2,670
5,470
8,200
15,800
25,200
44,500
90,800
125
600
1,250
2,360
4,850
7,270
14,000
22,300
39,500
80,500
150
544
1,140
2,140
4,400
6,590
12,700
20,200
35,700
72,900
175
500
1,050
1,970
4,040
6,060
11,700
18,600
32,900
67,100
200
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
250
412
862
1,620
3,330
5,000
9,620
15,300
27,100
55,300
300
374
781
1,470
3,020
4,530
8,720
13,900
24,600
50,100
350
344
719
1,350
2,780
4,170
8,020
12,800
22,600
46,100
400
320
669
1,260
2,590
3,870
7,460
11,900
21,000
42,900
450
300
627
1,180
2,430
3,640
7,000
11,200
19,700
40,200
500
283
593
1,120
2,290
3,430
6,610
10,500
18,600
38,000
550
269
563
1,060
2,180
3,260
6,280
10,000
17,700
36,100
600
257
537
1,010
2,080
3,110
5,990
9,550
16,900
34,400
650
246
514
969
1,990
2,980
5,740
9,150
16,200
33,000
700
236
494
931
1,910
2,860
5,510
8,790
15,500
31,700
750
228
476
897
1,840
2,760
5,310
8,470
15,000
30,500
800
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
850
213
445
838
1,720
2,580
4,960
7,910
14,000
28,500
900
206
431
812
1,670
2,500
4,810
7,670
13,600
27,700
950
200
419
789
1,620
2,430
4,670
7,450
13,200
26,900
1,000
195
407
767
1,580
2,360
4,550
7,240
12,800
26,100
1,100
185
387
729
1,500
2,240
4,320
6,890
12,200
24,800
1,200
177
369
695
1,430
2,140
4,120
6,570
11,600
23,700
1,300
169
353
666
1,370
2,050
3,940
6,290
11,100
22,700
1,400
162
340
640
1,310
1,970
3,790
6,040
10,700
21,800
1,500
156
327
616
1,270
1,900
3,650
5,820
10,300
21,000
1,600
151
316
595
1,220
1,830
3,530
5,620
10,000
20,300
1,700
146
306
576
1,180
1,770
3,410
5,440
9,610
19,600
1,800
142
296
558
1,150
1,720
3,310
5,270
9,320
19,000
1,900
138
288
542
1,110
1,670
3,210
5,120
9,050
18,400
2,000
134
280
527
1,080
1,620
3,120
4,980
8,800
18,000
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
TABLE 
402.4(7)
SCHEDULE 40 METALLIC PIPE
Gas
Natural
Inlet Pressure
5.0 psi
Pressure Drop
3.5 psi
Specific Gravity
0.60
PIPE SIZE (inch)
Nominal
1
/
2
3
/
4
1
1
1
/
4
1
1
/
2
2
2
1
/
2
3
4
Actual ID
0.622
0.824
1.049
1.380
1.610
2.067
2.469
3.068
4.026
Length (ft)
Capacity in Cubic Feet of Gas Per Hour
10
3,190
6,430
11,800
24,200
36,200
69,700
111,000
196,000
401,000
20
2,250
4,550
8,320
17,100
25,600
49,300
78,600
139,000
283,000
30
1,840
3,720
6,790
14,000
20,900
40,300
64,200
113,000
231,000
40
1,590
3,220
5,880
12,100
18,100
34,900
55,600
98,200
200,000
GAS PIPING INSTALLATIONS
50
1,430
2,880
5,260
10,800
16,200
31,200
49,700
87,900
179,000
60
1,300
2,630
4,800
9,860
14,800
28,500
45,400
80,200
164,000
70
1,200
2,430
4,450
9,130
13,700
26,400
42,000
74,300
151,000
80
1,150
2,330
4,260
8,540
12,800
24,700
39,300
69,500
142,000
90
1,060
2,150
3,920
8,050
12,100
23,200
37,000
65,500
134,000
100
979
1,980
3,620
7,430
11,100
21,400
34,200
60,400
123,000
125
876
1,770
3,240
6,640
9,950
19,200
30,600
54,000
110,000
150
786
1,590
2,910
5,960
8,940
17,200
27,400
48,500
98,900
175
728
1,470
2,690
5,520
8,270
15,900
25,400
44,900
91,600
200
673
1,360
2,490
5,100
7,650
14,700
23,500
41,500
84,700
250
558
1,170
2,200
4,510
6,760
13,000
20,800
36,700
74,900
300
506
1,060
1,990
4,090
6,130
11,800
18,800
33,300
67,800
350
465
973
1,830
3,760
5,640
10,900
17,300
30,600
62,400
400
433
905
1,710
3,500
5,250
10,100
16,100
28,500
58,100
450
406
849
1,600
3,290
4,920
9,480
15,100
26,700
54,500
500
384
802
1,510
3,100
4,650
8,950
14,300
25,200
51,500
550
364
762
1,440
2,950
4,420
8,500
13,600
24,000
48,900
600
348
727
1,370
2,810
4,210
8,110
12,900
22,900
46,600
650
333
696
1,310
2,690
4,030
7,770
12,400
21,900
44,600
700
320
669
1,260
2,590
3,880
7,460
11,900
21,000
42,900
750
308
644
1,210
2,490
3,730
7,190
11,500
20,300
41,300
800
298
622
1,170
2,410
3,610
6,940
11,100
19,600
39,900
850
288
602
1,130
2,330
3,490
6,720
10,700
18,900
38,600
900
279
584
1,100
2,260
3,380
6,520
10,400
18,400
37,400
950
271
567
1,070
2,190
3,290
6,330
10,100
17,800
36,400
1,000
264
551
1,040
2,130
3,200
6,150
9,810
17,300
35,400
1,100
250
524
987
2,030
3,030
5,840
9,320
16,500
33,600
1,200
239
500
941
1,930
2,900
5,580
8,890
15,700
32,000
1,300
229
478
901
1,850
2,770
5,340
8,510
15,000
30,700
1,400
220
460
866
1,780
2,660
5,130
8,180
14,500
29,500
1,500
212
443
834
1,710
2,570
4,940
7,880
13,900
28,400
1,600
205
428
806
1,650
2,480
4,770
7,610
13,400
27,400
1,700
198
414
780
1,600
2,400
4,620
7,360
13,000
26,500
1,800
192
401
756
1,550
2,330
4,480
7,140
12,600
25,700
1,900
186
390
734
1,510
2,260
4,350
6,930
12,300
25,000
2,000
181
379
714
1,470
2,200
4,230
6,740
11,900
24,300
For SI:
1 inch = 
25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1
-
inch water column = 0.2488 kPa,
1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m
3
/h, 1 degree = 0.01745 rad.
Note: 
All table entries have been rounded to three 
significant digits.
402.5 Allowable pressure drop.
The design pressure loss in any piping system under maximum probable flow con-
ditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the 
appl
iance is greater than or equal to the minimum pressure required by 
the
appliance.
402.6 
Gas distribution pressures.
The maximum design operating pressure for piping systems located inside build-
ings shall not exceed 
1
/
2
pounds per square inch gauge (psig) (
3.5
kPa gauge).
Exceptions:
1.
Pressure not exceeding 5 psig (34.5 kPa gauge) is permitted
where 
a system supplies
o
ne or more 
appliances 
that require gas pressure in excess of 
1
/
2
psig (3.5 kPa gauge)
.
2.
Gas pressure not exceeding 15 psig (
103.4
kPa gauge) is permitted for appliances in excess of 100,000 cubic 
feet per hour (2830 m
3
/h) provided the gas 
distribution piping is installed as provided for in Section 404.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
411.1.5 Connection of gas engine
-
powered air conditioners.
Internal combustion engines shall not be rigidly 
connected to the gas supply piping.
411.1.6 Unions.
A union fitting shall be provided for appliances connected
by rigid metallic pipe. Such unions 
shall be accessible and located within 6 feet (
1828.8
mm) of the appliance.
411.2 Manufactured home connections.
Manufactured homes shall be connected to the distribution piping system 
by one of the following materials:
1.
Metallic pipe in accordance with Section 403.4.
2.
Listed and labeled connectors in compliance with ANSI Z21.75/CSA 6.27 and installed in accordance with the 
manufacturer’s 
instructions
.
411.3 Suspended low
-
intensity infrared tube heaters.
Suspended lo
w
-
intensity infrared tube heaters shall be con-
nected to the building piping system with a connector listed for the application complying with ANSI Z21.24/CGA 
6.10. The connector shall be installed as specified by the tube heater manufacturer’s instructions
.
SECTION FGC 412
LIQUEFIED PETROLEUM GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
412.1 
Applicability.
Motor fuel
-
dispensing facilities for LP
-
gas fuel shall be 
designed and operated
in accordance with the 
New York City
Fire Code
.
412.2 Reserved.
412.3 Reserved.
412.4 Reserved.
412.5 Reserved.
412.6 Reserved.
412.7 Reserved.
412.8 Reserved.
SECTION FGC 413
COMPRESSED NATURAL GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
413.1 Applicability.
Motor fuel
-
dispensing facilities for CNG fuel shall be 
designed and operated
in accordance with 
the 
New York City
Fire Code
.
413.2 Reserved.
413.3 Reserved.
413.4 Reserved.
413.5 Reserved.
413.6 Reserved.
413.7 Reserved.
413.8 Reserved.
SECTION FGC 414
RE
SERVED
GAS PIPING INSTALLATIONS
SECTION FGC 415
PIPING SUPPORT INTERVALS
415.1 Interval of support.
Piping shall be supported at intervals not exceeding the spacing specified in Table 415.1.
TABLE 415.1
SUPPORT OF PIPING
STEEL PIPE, NOMINAL SIZE OF PIPE
(inches)
SPACING OF 
SUPPORTS
(feet)
1
/
2
6
3
/
4
or 1
8
1
1
/
4
or larger (horizontal)
12
All vertical piping
Every floor level
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
SECTION FGC 416
OVERPRESSURE PROTECTION DEVICES
416.1 
Where required.
Where the serving gas supplier delivers gas at a pressure greater than 2 psi 
(13.79 kPa)
for 
piping systems serving appliances designed to operate at a gas pressure of 14 inches w.c. 
(3.49 kPa)
or less, overpres-
sure protection devices shall be installed. 
Piping systems serving 
appliances
designed to operate at inlet pressures 
greater than 14 inches w.c. 
(3.49 kPa)
shall be equipped with overpressure protection devices as required by the ap-
pliance manufacturer’s instructions.
416.2 
Pressure limitation requi
rements.
The requirements for pressure limitation shall be in accordance with Sec-
tions 416.2.1 through 416.2.5.
416.2.1 Pressure under 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure of 14 inches w.c. 
(3.49 kPa)
or less are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to
limit the gas pressure to each connected 
appliance to 2 psi or less upon a failure of the line pressure regulator.
416.2.2 Pressure over 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure greater than 14 
inches w.c. 
(3.49 kPa)
are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to limit the gas pressure to each connected 
appliance as required by the appliance manufacturer’s instru
ctions. 
416.2.3 Device capability.
Each overpressure protection device installed to meet the requirements of this section 
shall be capable of limiting the pressure to its connected appliance(s) as required by Section 416.2.1, independently 
of any other pr
essure control equipment in the piping system.
416.2.4 Failure detection.
Each gas piping system for which an overpressure protection device is required by 
Section 416 shall be designed and installed so that a failure of the primary pressure control device
(s) is detectable. 
416.2.5 Relief valve.
Where a pressure relief valve is used to meet the requirements of Section 416, it shall have a 
flow capacity such that the pressure in the protected system is maintained at or below the limits specified in Section 
416.2.1 under all of the following conditions:
1.
The line pressure regulator for which the relief valve is providing overpressure protection has failed wide 
open.
2.
The gas pressure at the inlet of the line pressure regulator for which the relief valve i
s providing overpressure 
protection is not less than the regulator’s normal operating inlet pressure.
GAS PIPING INSTALLATIONS
3.
The use of pressure in excess of 15 psig (
103.4
kPa gauge) shall be permitted for distribution piping provided 
all of the requirements of Section 406 and Appendix G are met.
SECTION FGC 
403
PIPING MATERIALS
403.1 General.
Materials used for piping systems shall 
be new and
comply with the requirements of this chapter or 
shall be approved.
403.1.1 Pipe size and pressure limitations.
1.
All requirements for installation of gas distribution p
iping shall be in accordance with Chapter 4. 
Gas distri-
bution piping with operating pressures of 15 psig (103.4 kPa gauge) or more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
411.1.5 Connection of gas engine
-
powered air conditioners.
Internal combustion engines shall not be rigidly 
connected to the gas supply piping.
411.1.6 Unions.
A union fitting shall be provided for appliances connected
by rigid metallic pipe. Such unions 
shall be accessible and located within 6 feet (
1828.8
mm) of the appliance.
411.2 Manufactured home connections.
Manufactured homes shall be connected to the distribution piping system 
by one of the following materials:
1.
Metallic pipe in accordance with Section 403.4.
2.
Listed and labeled connectors in compliance with ANSI Z21.75/CSA 6.27 and installed in accordance with the 
manufacturer’s 
instructions
.
411.3 Suspended low
-
intensity infrared tube heaters.
Suspended lo
w
-
intensity infrared tube heaters shall be con-
nected to the building piping system with a connector listed for the application complying with ANSI Z21.24/CGA 
6.10. The connector shall be installed as specified by the tube heater manufacturer’s instructions
.
SECTION FGC 412
LIQUEFIED PETROLEUM GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
412.1 
Applicability.
Motor fuel
-
dispensing facilities for LP
-
gas fuel shall be 
designed and operated
in accordance with the 
New York City
Fire Code
.
412.2 Reserved.
412.3 Reserved.
412.4 Reserved.
412.5 Reserved.
412.6 Reserved.
412.7 Reserved.
412.8 Reserved.
SECTION FGC 413
COMPRESSED NATURAL GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
413.1 Applicability.
Motor fuel
-
dispensing facilities for CNG fuel shall be 
designed and operated
in accordance with 
the 
New York City
Fire Code
.
413.2 Reserved.
413.3 Reserved.
413.4 Reserved.
413.5 Reserved.
413.6 Reserved.
413.7 Reserved.
413.8 Reserved.
SECTION FGC 414
RE
SERVED
GAS PIPING INSTALLATIONS
SECTION FGC 415
PIPING SUPPORT INTERVALS
415.1 Interval of support.
Piping shall be supported at intervals not exceeding the spacing specified in Table 415.1.
TABLE 415.1
SUPPORT OF PIPING
STEEL PIPE, NOMINAL SIZE OF PIPE
(inches)
SPACING OF 
SUPPORTS
(feet)
1
/
2
6
3
/
4
or 1
8
1
1
/
4
or larger (horizontal)
12
All vertical piping
Every floor level
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
SECTION FGC 416
OVERPRESSURE PROTECTION DEVICES
416.1 
Where required.
Where the serving gas supplier delivers gas at a pressure greater than 2 psi 
(13.79 kPa)
for 
piping systems serving appliances designed to operate at a gas pressure of 14 inches w.c. 
(3.49 kPa)
or less, overpres-
sure protection devices shall be installed. 
Piping systems serving 
appliances
designed to operate at inlet pressures 
greater than 14 inches w.c. 
(3.49 kPa)
shall be equipped with overpressure protection devices as required by the ap-
pliance manufacturer’s instructions.
416.2 
Pressure limitation requi
rements.
The requirements for pressure limitation shall be in accordance with Sec-
tions 416.2.1 through 416.2.5.
416.2.1 Pressure under 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure of 14 inches w.c. 
(3.49 kPa)
or less are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to
limit the gas pressure to each connected 
appliance to 2 psi or less upon a failure of the line pressure regulator.
416.2.2 Pressure over 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure greater than 14 
inches w.c. 
(3.49 kPa)
are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to limit the gas pressure to each connected 
appliance as required by the appliance manufacturer’s instru
ctions. 
416.2.3 Device capability.
Each overpressure protection device installed to meet the requirements of this section 
shall be capable of limiting the pressure to its connected appliance(s) as required by Section 416.2.1, independently 
of any other pr
essure control equipment in the piping system.
416.2.4 Failure detection.
Each gas piping system for which an overpressure protection device is required by 
Section 416 shall be designed and installed so that a failure of the primary pressure control device
(s) is detectable. 
416.2.5 Relief valve.
Where a pressure relief valve is used to meet the requirements of Section 416, it shall have a 
flow capacity such that the pressure in the protected system is maintained at or below the limits specified in Section 
416.2.1 under all of the following conditions:
1.
The line pressure regulator for which the relief valve is providing overpressure protection has failed wide 
open.
2.
The gas pressure at the inlet of the line pressure regulator for which the relief valve i
s providing overpressure 
protection is not less than the regulator’s normal operating inlet pressure.
GAS PIPING INSTALLATIONS
416.3
Devices.
Pressure
-
relieving or pressure
-
limiting devices shall be one of the following:
1.
Pressure relief valve.
2.
Monitoring regulator.
3.
Series
regulator installed 
upstream from the
line regulator 
and set to continuously limit the pressure on the inlet 
of the line regulator to the maximum values specified by Section 416.2.1.
4.
Automatic
shutoff device installed in series with 
the line
pressure r
egulator and set to shut off when the pressure 
on the downstream piping system reaches the maximum 
values specified by Section 416.2.1.
This device shall 
be designed so that it will remain closed until manually reset.
The devices 
specified in this section
shall be installed either as an integral part of the service or line pressure 
regulator or as separate units. Where separate pressure
-
relieving or pressure
-
limiting devices are installed, they shall 
comply with Sections 
416.3.1
through 
416.3.6
.
416.3.1
Con
struction and installation.
Pressure
-
relieving
and pressure
-
limiting devices shall be constructed of 
materials so that the operation of the devices will not be impaired by corrosion of external parts by the atmosphere 
or of internal parts by the gas. Press
ure
-
relieving and pressure
-
limiting devices shall be designed and installed so 
that they can be operated to determine whether the valve is free. The devices 
shall be
designed and installed so that 
they can be tested to determine the pressure at which they 
will operate and examined for leakage when in the closed 
position. 
The devices shall be maintained and inspected in accordance with Section 416.3.7.
416.3.2
External control piping.
External control piping shall 
be designed
and installed so that damage to 
the
control piping 
of one device
will not render both the regulator and the overpressure 
protection
device inoperative.
416.3.3
Setting.
Each pressure
-
relieving or pressure
-
limiting device shall be set so that the 
gas
pressure 
supplied 
to
the connected appliances 
does not exceed the limits specified in Section 416.2.1
.
416.3.4
Unauthorized operation.
Precautions shall be taken to prevent
u
nauthorized operation of any shutoff 
valve 
that will make
a 
pressure
-
relieving
valve or pressure
-
limiting device inoperative. The valve shall be locked 
or
continuously monitored
in the open position.
416.3.5
Vents.
The discharge stacks, vents and outlet pa
rts of all pressure
-
relieving and pressure
-
limiting devices 
shall be located so that gas is safely discharged to the outdoors. Discharge stacks and vents shall be designed to 
prevent the entry of water, insects and other foreign material that could cause b
lockage. The discharge stack or vent 
line shall be 
not less than
the same size as the outlet of the pressure
-
relieving device.
416.3.6
Size of fittings, pipe and openings.
The fittings, pipe and openings located between the system to be 
protected and the p
ressure
-
relieving device shall be sized to prevent hammering of the valve and to prevent impair-
ment of relief capacity.
416.3.7 Device maintenance.
The overpressure protection device: (i) shall be properly maintained and inspected 
every two years by a lice
nsed master plumber; (ii) inspection records shall be maintained by the owner and made 
available to the department; (iii) inspection procedures shall be in accordance with the commissioner; and (iv) 
replacements or repairs shall be promptly made.
Exception
:
Where the gas pressure is 15 psig (103.4 kPa gauge) or above, the overpressure protection device 
shall be inspected annually.more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
411.1.5 Connection of gas engine
-
powered air conditioners.
Internal combustion engines shall not be rigidly 
connected to the gas supply piping.
411.1.6 Unions.
A union fitting shall be provided for appliances connected
by rigid metallic pipe. Such unions 
shall be accessible and located within 6 feet (
1828.8
mm) of the appliance.
411.2 Manufactured home connections.
Manufactured homes shall be connected to the distribution piping system 
by one of the following materials:
1.
Metallic pipe in accordance with Section 403.4.
2.
Listed and labeled connectors in compliance with ANSI Z21.75/CSA 6.27 and installed in accordance with the 
manufacturer’s 
instructions
.
411.3 Suspended low
-
intensity infrared tube heaters.
Suspended lo
w
-
intensity infrared tube heaters shall be con-
nected to the building piping system with a connector listed for the application complying with ANSI Z21.24/CGA 
6.10. The connector shall be installed as specified by the tube heater manufacturer’s instructions
.
SECTION FGC 412
LIQUEFIED PETROLEUM GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
412.1 
Applicability.
Motor fuel
-
dispensing facilities for LP
-
gas fuel shall be 
designed and operated
in accordance with the 
New York City
Fire Code
.
412.2 Reserved.
412.3 Reserved.
412.4 Reserved.
412.5 Reserved.
412.6 Reserved.
412.7 Reserved.
412.8 Reserved.
SECTION FGC 413
COMPRESSED NATURAL GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
413.1 Applicability.
Motor fuel
-
dispensing facilities for CNG fuel shall be 
designed and operated
in accordance with 
the 
New York City
Fire Code
.
413.2 Reserved.
413.3 Reserved.
413.4 Reserved.
413.5 Reserved.
413.6 Reserved.
413.7 Reserved.
413.8 Reserved.
SECTION FGC 414
RE
SERVED
GAS PIPING INSTALLATIONS
SECTION FGC 415
PIPING SUPPORT INTERVALS
415.1 Interval of support.
Piping shall be supported at intervals not exceeding the spacing specified in Table 415.1.
TABLE 415.1
SUPPORT OF PIPING
STEEL PIPE, NOMINAL SIZE OF PIPE
(inches)
SPACING OF 
SUPPORTS
(feet)
1
/
2
6
3
/
4
or 1
8
1
1
/
4
or larger (horizontal)
12
All vertical piping
Every floor level
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
SECTION FGC 416
OVERPRESSURE PROTECTION DEVICES
416.1 
Where required.
Where the serving gas supplier delivers gas at a pressure greater than 2 psi 
(13.79 kPa)
for 
piping systems serving appliances designed to operate at a gas pressure of 14 inches w.c. 
(3.49 kPa)
or less, overpres-
sure protection devices shall be installed. 
Piping systems serving 
appliances
designed to operate at inlet pressures 
greater than 14 inches w.c. 
(3.49 kPa)
shall be equipped with overpressure protection devices as required by the ap-
pliance manufacturer’s instructions.
416.2 
Pressure limitation requi
rements.
The requirements for pressure limitation shall be in accordance with Sec-
tions 416.2.1 through 416.2.5.
416.2.1 Pressure under 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure of 14 inches w.c. 
(3.49 kPa)
or less are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to
limit the gas pressure to each connected 
appliance to 2 psi or less upon a failure of the line pressure regulator.
416.2.2 Pressure over 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure greater than 14 
inches w.c. 
(3.49 kPa)
are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to limit the gas pressure to each connected 
appliance as required by the appliance manufacturer’s instru
ctions. 
416.2.3 Device capability.
Each overpressure protection device installed to meet the requirements of this section 
shall be capable of limiting the pressure to its connected appliance(s) as required by Section 416.2.1, independently 
of any other pr
essure control equipment in the piping system.
416.2.4 Failure detection.
Each gas piping system for which an overpressure protection device is required by 
Section 416 shall be designed and installed so that a failure of the primary pressure control device
(s) is detectable. 
416.2.5 Relief valve.
Where a pressure relief valve is used to meet the requirements of Section 416, it shall have a 
flow capacity such that the pressure in the protected system is maintained at or below the limits specified in Section 
416.2.1 under all of the following conditions:
1.
The line pressure regulator for which the relief valve is providing overpressure protection has failed wide 
open.
2.
The gas pressure at the inlet of the line pressure regulator for which the relief valve i
s providing overpressure 
protection is not less than the regulator’s normal operating inlet pressure.
GAS PIPING INSTALLATIONS
416.3
Devices.
Pressure
-
relieving or pressure
-
limiting devices shall be one of the following:
1.
Pressure relief valve.
2.
Monitoring regulator.
3.
Series
regulator installed 
upstream from the
line regulator 
and set to continuously limit the pressure on the inlet 
of the line regulator to the maximum values specified by Section 416.2.1.
4.
Automatic
shutoff device installed in series with 
the line
pressure r
egulator and set to shut off when the pressure 
on the downstream piping system reaches the maximum 
values specified by Section 416.2.1.
This device shall 
be designed so that it will remain closed until manually reset.
The devices 
specified in this section
shall be installed either as an integral part of the service or line pressure 
regulator or as separate units. Where separate pressure
-
relieving or pressure
-
limiting devices are installed, they shall 
comply with Sections 
416.3.1
through 
416.3.6
.
416.3.1
Con
struction and installation.
Pressure
-
relieving
and pressure
-
limiting devices shall be constructed of 
materials so that the operation of the devices will not be impaired by corrosion of external parts by the atmosphere 
or of internal parts by the gas. Press
ure
-
relieving and pressure
-
limiting devices shall be designed and installed so 
that they can be operated to determine whether the valve is free. The devices 
shall be
designed and installed so that 
they can be tested to determine the pressure at which they 
will operate and examined for leakage when in the closed 
position. 
The devices shall be maintained and inspected in accordance with Section 416.3.7.
416.3.2
External control piping.
External control piping shall 
be designed
and installed so that damage to 
the
control piping 
of one device
will not render both the regulator and the overpressure 
protection
device inoperative.
416.3.3
Setting.
Each pressure
-
relieving or pressure
-
limiting device shall be set so that the 
gas
pressure 
supplied 
to
the connected appliances 
does not exceed the limits specified in Section 416.2.1
.
416.3.4
Unauthorized operation.
Precautions shall be taken to prevent
u
nauthorized operation of any shutoff 
valve 
that will make
a 
pressure
-
relieving
valve or pressure
-
limiting device inoperative. The valve shall be locked 
or
continuously monitored
in the open position.
416.3.5
Vents.
The discharge stacks, vents and outlet pa
rts of all pressure
-
relieving and pressure
-
limiting devices 
shall be located so that gas is safely discharged to the outdoors. Discharge stacks and vents shall be designed to 
prevent the entry of water, insects and other foreign material that could cause b
lockage. The discharge stack or vent 
line shall be 
not less than
the same size as the outlet of the pressure
-
relieving device.
416.3.6
Size of fittings, pipe and openings.
The fittings, pipe and openings located between the system to be 
protected and the p
ressure
-
relieving device shall be sized to prevent hammering of the valve and to prevent impair-
ment of relief capacity.
416.3.7 Device maintenance.
The overpressure protection device: (i) shall be properly maintained and inspected 
every two years by a lice
nsed master plumber; (ii) inspection records shall be maintained by the owner and made 
available to the department; (iii) inspection procedures shall be in accordance with the commissioner; and (iv) 
replacements or repairs shall be promptly made.
Exception
:
Where the gas pressure is 15 psig (103.4 kPa gauge) or above, the overpressure protection device 
shall be inspected annually.more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
411.1.5 Connection of gas engine
-
powered air conditioners.
Internal combustion engines shall not be rigidly 
connected to the gas supply piping.
411.1.6 Unions.
A union fitting shall be provided for appliances connected
by rigid metallic pipe. Such unions 
shall be accessible and located within 6 feet (
1828.8
mm) of the appliance.
411.2 Manufactured home connections.
Manufactured homes shall be connected to the distribution piping system 
by one of the following materials:
1.
Metallic pipe in accordance with Section 403.4.
2.
Listed and labeled connectors in compliance with ANSI Z21.75/CSA 6.27 and installed in accordance with the 
manufacturer’s 
instructions
.
411.3 Suspended low
-
intensity infrared tube heaters.
Suspended lo
w
-
intensity infrared tube heaters shall be con-
nected to the building piping system with a connector listed for the application complying with ANSI Z21.24/CGA 
6.10. The connector shall be installed as specified by the tube heater manufacturer’s instructions
.
SECTION FGC 412
LIQUEFIED PETROLEUM GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
412.1 
Applicability.
Motor fuel
-
dispensing facilities for LP
-
gas fuel shall be 
designed and operated
in accordance with the 
New York City
Fire Code
.
412.2 Reserved.
412.3 Reserved.
412.4 Reserved.
412.5 Reserved.
412.6 Reserved.
412.7 Reserved.
412.8 Reserved.
SECTION FGC 413
COMPRESSED NATURAL GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
413.1 Applicability.
Motor fuel
-
dispensing facilities for CNG fuel shall be 
designed and operated
in accordance with 
the 
New York City
Fire Code
.
413.2 Reserved.
413.3 Reserved.
413.4 Reserved.
413.5 Reserved.
413.6 Reserved.
413.7 Reserved.
413.8 Reserved.
SECTION FGC 414
RE
SERVED
GAS PIPING INSTALLATIONS
SECTION FGC 415
PIPING SUPPORT INTERVALS
415.1 Interval of support.
Piping shall be supported at intervals not exceeding the spacing specified in Table 415.1.
TABLE 415.1
SUPPORT OF PIPING
STEEL PIPE, NOMINAL SIZE OF PIPE
(inches)
SPACING OF 
SUPPORTS
(feet)
1
/
2
6
3
/
4
or 1
8
1
1
/
4
or larger (horizontal)
12
All vertical piping
Every floor level
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
SECTION FGC 416
OVERPRESSURE PROTECTION DEVICES
416.1 
Where required.
Where the serving gas supplier delivers gas at a pressure greater than 2 psi 
(13.79 kPa)
for 
piping systems serving appliances designed to operate at a gas pressure of 14 inches w.c. 
(3.49 kPa)
or less, overpres-
sure protection devices shall be installed. 
Piping systems serving 
appliances
designed to operate at inlet pressures 
greater than 14 inches w.c. 
(3.49 kPa)
shall be equipped with overpressure protection devices as required by the ap-
pliance manufacturer’s instructions.
416.2 
Pressure limitation requi
rements.
The requirements for pressure limitation shall be in accordance with Sec-
tions 416.2.1 through 416.2.5.
416.2.1 Pressure under 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure of 14 inches w.c. 
(3.49 kPa)
or less are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to
limit the gas pressure to each connected 
appliance to 2 psi or less upon a failure of the line pressure regulator.
416.2.2 Pressure over 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure greater than 14 
inches w.c. 
(3.49 kPa)
are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to limit the gas pressure to each connected 
appliance as required by the appliance manufacturer’s instru
ctions. 
416.2.3 Device capability.
Each overpressure protection device installed to meet the requirements of this section 
shall be capable of limiting the pressure to its connected appliance(s) as required by Section 416.2.1, independently 
of any other pr
essure control equipment in the piping system.
416.2.4 Failure detection.
Each gas piping system for which an overpressure protection device is required by 
Section 416 shall be designed and installed so that a failure of the primary pressure control device
(s) is detectable. 
416.2.5 Relief valve.
Where a pressure relief valve is used to meet the requirements of Section 416, it shall have a 
flow capacity such that the pressure in the protected system is maintained at or below the limits specified in Section 
416.2.1 under all of the following conditions:
1.
The line pressure regulator for which the relief valve is providing overpressure protection has failed wide 
open.
2.
The gas pressure at the inlet of the line pressure regulator for which the relief valve i
s providing overpressure 
protection is not less than the regulator’s normal operating inlet pressure.
GAS PIPING INSTALLATIONS
416.3
Devices.
Pressure
-
relieving or pressure
-
limiting devices shall be one of the following:
1.
Pressure relief valve.
2.
Monitoring regulator.
3.
Series
regulator installed 
upstream from the
line regulator 
and set to continuously limit the pressure on the inlet 
of the line regulator to the maximum values specified by Section 416.2.1.
4.
Automatic
shutoff device installed in series with 
the line
pressure r
egulator and set to shut off when the pressure 
on the downstream piping system reaches the maximum 
values specified by Section 416.2.1.
This device shall 
be designed so that it will remain closed until manually reset.
The devices 
specified in this section
shall be installed either as an integral part of the service or line pressure 
regulator or as separate units. Where separate pressure
-
relieving or pressure
-
limiting devices are installed, they shall 
comply with Sections 
416.3.1
through 
416.3.6
.
416.3.1
Con
struction and installation.
Pressure
-
relieving
and pressure
-
limiting devices shall be constructed of 
materials so that the operation of the devices will not be impaired by corrosion of external parts by the atmosphere 
or of internal parts by the gas. Press
ure
-
relieving and pressure
-
limiting devices shall be designed and installed so 
that they can be operated to determine whether the valve is free. The devices 
shall be
designed and installed so that 
they can be tested to determine the pressure at which they 
will operate and examined for leakage when in the closed 
position. 
The devices shall be maintained and inspected in accordance with Section 416.3.7.
416.3.2
External control piping.
External control piping shall 
be designed
and installed so that damage to 
the
control piping 
of one device
will not render both the regulator and the overpressure 
protection
device inoperative.
416.3.3
Setting.
Each pressure
-
relieving or pressure
-
limiting device shall be set so that the 
gas
pressure 
supplied 
to
the connected appliances 
does not exceed the limits specified in Section 416.2.1
.
416.3.4
Unauthorized operation.
Precautions shall be taken to prevent
u
nauthorized operation of any shutoff 
valve 
that will make
a 
pressure
-
relieving
valve or pressure
-
limiting device inoperative. The valve shall be locked 
or
continuously monitored
in the open position.
416.3.5
Vents.
The discharge stacks, vents and outlet pa
rts of all pressure
-
relieving and pressure
-
limiting devices 
shall be located so that gas is safely discharged to the outdoors. Discharge stacks and vents shall be designed to 
prevent the entry of water, insects and other foreign material that could cause b
lockage. The discharge stack or vent 
line shall be 
not less than
the same size as the outlet of the pressure
-
relieving device.
416.3.6
Size of fittings, pipe and openings.
The fittings, pipe and openings located between the system to be 
protected and the p
ressure
-
relieving device shall be sized to prevent hammering of the valve and to prevent impair-
ment of relief capacity.
416.3.7 Device maintenance.
The overpressure protection device: (i) shall be properly maintained and inspected 
every two years by a lice
nsed master plumber; (ii) inspection records shall be maintained by the owner and made 
available to the department; (iii) inspection procedures shall be in accordance with the commissioner; and (iv) 
replacements or repairs shall be promptly made.
Exception
:
Where the gas pressure is 15 psig (103.4 kPa gauge) or above, the overpressure protection device 
shall be inspected annually.more shall be in accordance with 
Appendix G.
2.
Gas distribution piping operating at a pressure of over 
1
/
2
psig (3.5 kPa gauge) s
hall be welded.
Exception:
Manufactured and listed gas trains provided with the appliance may be threaded.
3.
All welding of gas distribution piping shall be subject to 
radiography or
special inspection as set forth in 
Section 406.
4.
Threaded piping may b
e used up to 4 inches (
101.6
mm) 
in diameter
at pressure no greater than 
1
/
2
psig (3.5 
kPa gauge). 
All piping greater than 4 inches in diameter shall be welded, regardless of operating pressure.
5.
All welded piping 2
1
/
2
inches (63.5 mm) or greater in diameter shall be butt
-
welded, and welded piping less 
than 2
1
/
2
inches (63.5 mm) in diameter may be socket
-
welded or butt
-
welded.
403.2 Used materials.
Used pipe
, fittings, valves and other materials shall not be 
reused
.
403
.3 Other materials.
Material not covered by the standards specifications listed herein shall be investigated and 
tested to determine that it is safe and suitable for the proposed service, and, in addition, shall be recommended for that 
service by the manuf
acturer 
subject to approval
by the 
commissioner
.
403.4 Metallic pipe.
Metallic pipe shall comply with Sections 403.4.1 through 403.4.4.
403.4.1 Cast iron.
Cast
-
iron pipe shall not be used.
403.4.2 Steel.
Carbon steel
and wrought
-
iron pipe shall be 
not less
than
standard weight and shall comply with one 
of the following standards:
1.
ASME 
B36.10M.
2.
ASTM A 53/
A 53M
.
3.
ASTM 
A106/A106M
.
403.4.3 Copper and 
brass.
Copper and 
brass
pipe shall not be used.
403.4.4 Aluminum.
Aluminum
-
alloy pipe shall not be used.
403.5 Metallic tubing.
Metallic
tubing shall not be used 
except as provided in Section 
404.2
.
403.5.1 
Standards.
Stainless steel flexible multiple leg hose assemblies
shall be 
listed
and labeled
in accordance 
with
UL
536
and
designed
in accordance with 
the manufacturer’s recommendation
.
403.5.2 Seismic requirements.
Stainless steel flexible multiple leg hose assemblies shall be designed to withstand 
seismic force and displacement in accordance with Section 1613 of the
New York City Building Code
.
403.5.3 Special inspection required.
The installation of stainless steel flexible multiple leg hose assemblies shall 
be subject to special inspection in accordance with Section 
1705.12.3
of the 
New York City Building Code
and 
Section 406 of this code.
403.6 Reserved.
GAS PIPING INSTALLATIONS
403.7 Workmanship and defects.
Pipe and fittings shall be clear and free from cutting burrs and defects in structure 
or threading, and shall be thoroughly brushed, and chip and scale blown.
Defects in pipe and
fittings shall not be repaired. Defective pipe and fittings shall be replaced 
(see Section 406.1.2).
403.8 Protective coating.
Where in contact with material or atmosphere exerting a corrosive action, metallic piping 
and fittings coated with a corrosion
-
r
esistant material shall be used. External coatings or linings used on piping or 
components shall not be considered as adding strength.
403.9 Metallic pipe threads.
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME 
B1.
20.1.
403.9.1 Damaged threads.
Pipe with threads that are stripped, chipped, corroded or otherwise damaged shall not 
be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used.
403.9.2 Number of threads.
Field threading of metal
lic pipe shall be in accordance with Table 403.9.2.
TABLE 403.9.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
IRON PIPE SIZE
(inches)
APPROXIMATE LENGTH 
OF THREADED PORTION
(inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
1
/
2
3
/
4
10
3
/
4
3
/
4
10
1
7
/
8
10
1
1
/
4
1
11
1
1
/
2
1
11
2
1
11
2
1
/
2
1
1
/
2
12
3
1
1
/
2
12
4
1
5
/
8
13
For SI: 1 inch = 25.4 mm
403.9.3 Thread 
joint
compounds.
Thread 
joint compounds
shall be in non
-
hardening paste or tape form and
shall 
be resistant to the action of liquefied petroleum gas or to any other chemical constituents of the gases to be con-
ducted through the piping. 
Use of cotton thread (lamp wick) is prohibited.
Threaded joint compound in tape form 
is prohibited for 
use at pressure regulator connections.
403.10 Metallic piping joints and fittings.
The type of piping joint used shall be suitable for the pressure
-
temperature 
conditions and shall be selected giving consideration to joint tightness and mechanical strength
under the service 
conditions. The joint shall be able to sustain the maximum end force caused by the internal pressure and any additional 
forces caused by temperature expansion or contraction, vibration, fatigue or the weight of the pipe and its contents.
403.10.1 Pipe joints.
Pipe joints shall be threaded, flanged, or welded.
403.10.1.1 Prohibited joints and fittings.
Unions and threaded close nipples shall be prohibited.
Exception:
Unions shall be permitted to be installed downstream of the appliance val
ve in accordance with 
Section 411.1.6.
403.10.2 Tubing joints.
Tubing joints shall 
not be used
.
403.10.3 Flared joints.
Flared joints shall 
not be used
.
403.10.4 Metallic fittings.
Metallic fittings shall comply with the following:
1.
Threaded fittings in 
sizes larger than 4 inches (
101.6
mm) shall not be used.
2.
Fittings used with steel or wrought
-
iron pipe shall be steel 
or
malleable iron.
GAS PIPING INSTALLATIONS
3.
Bushings shall not be used.
403.11 Reserved.
403.12 Flanges.
Flanges and flange gaskets
shall comply with 
Sections 403.12.1 through 403.12.7
.
403.12.1
Cast
-
iron.
Cast
-
iron flanges shall 
not be used
.
403.12.2 Steel.
Steel flanges shall be in accordance with ASME 
B16
.5 or ASME 
B16
.47.
403.12.3 Nonferrous.
Nonferrous flanges shall 
not be used
.
403.12.4 Ductile iron.
Ductile
-
iron flanges shall be in accordance with ASME 
B16
.42.
403.12.5 Raised face.
Raised face flanges shall not be joined to flat faced cast
-
iron, ductile
-
iron or nonferrous 
material flanges.
403.12.6 Flange facings.
Standard facin
gs shall be permitted for use under this code. Where 150 pound (1034 kPa) 
pressure
-
rated steel flanges are bolted to Class 125 cast
-
iron flanges, the raised face on the steel flange shall be 
removed.
403.12.7 Lapped flanges.
Lapped flanges shall be used on
ly above ground or in exposed locations accessible for 
inspection.
403.13 Flange gaskets.
Material for gaskets shall be capable of withstanding the design temperature and pressure of 
the piping system, and the chemical constituents of the gas being conducted, without change to its chemical and 
physical properties. The effects of fire exposure 
to the joint shall be considered in choosing material. Acceptable 
materials include metal 
(plain or corrugated),
non
-
asbestos
fiber
,
and
spiral wound metal gaskets. 
Where
a flanged 
joint is opened, the gasket shall be replaced. Full
-
face 
flange
gaskets sha
ll be used with all 
non
-
steel
flanges.
Rubber
-
faced phenolic and elastomeric gaskets shall be prohibited.
403.13.1 Metallic gaskets.
Metallic flange gaskets shall be in accordance with ASME 
B16
.20.
403.13.2 Nonmetallic gaskets.
Nonmetallic flange gaskets s
hall be in accordance with ASME 
B16
.21.
403.14 Flange bolts.
Flange bolts and associated hardware shall be manufactured from corrosion
-
resistant materials.
SECTION FGC 404
PIPING SYSTEM INSTALLATION
404.1 Installation of materials.
Materials used shall be 
installed in strict accordance with the standards under which 
the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions 
shall be followed. Where the requirements of referenced standards or manu
facturer’s instructions do not conform to 
minimum provisions of this code, the provisions of this code shall apply.
404.2 
Pipe movement.
Flammable or combustible gas
piping systems shall be 
designed to account for pipe movement 
resulting from thermal chang
es or seismic forces.
404.2.1 Seismic requirements.
Gas piping shall be designed and
installed 
to withstand seismic forces
in accord-
ance with 
Section 1613 of
the 
New York City Building Code
.
404.2.1.1 Stainless steel flexible multiple leg hose 
assemblies.
Stainless steel flexible multiple leg hose as-
semblies may be installed where pipe movement resulting from seismic forces may occur. Such assemblies shall 
be listed and labeled in accordance with UL 536 and shall be installed in accordance with 
the
manufacturer’s 
instructions.
404.2.1.2 Inspection.
The installation of stainless steel flexible multiple leg hose assemblies shall be subject to 
special inspections in accordance with Chapter 17 of the 
New York City Building Code
.
404.3
Prohibited loca
tions.
Piping shall not be installed in or through a ducted supply, return or exhaust 
duct
, or a 
trash or
clothes chute, chimney or gas vent
, ventilating duct
, dumbwaiter or elevator shaft. Piping installed downstream 
of the point of delivery shall not ext
end through any townhouse unit other than the unit served by such piping. 
Piping, 
GAS PIPING INSTALLATIONS
fixtures, or equipment shall be located so as not to interfere with the normal operation of windows or doors and other 
exit openings. The following installation limitations s
hall apply:
1.
Stair enclosures.
Gas piping shall not be installed within a stair enclosure or required exit or exit way.
2.
Fire standpipe riser.
Gas piping shall not be installed in any shaft containing standpipe risers.
3.
Fire pump and fire pump rooms.
Gas piping, gas consumption devices
, appliances
or any other gas equipment 
shall not be installed within any space housing a fire pump. Access to gas meter rooms shall not be permitted 
through
rooms housing a fire pump.
4.
Fire
-
rated 
construction.
Gas piping shall not be installed within 
a wall or assembly required to have a fire
-
resistance rating. Through penetrations of fire
-
resistance
-
rated assemblies shall be in accordance with Chapter 
7 of the 
New York City Building Code
.
5.
Publi
c corridor.
Gas piping shall not be installed in public corridors and exit enclosures.
Exceptions:
1.
Gas piping may be installed in public corridors or exit enclosures where separated by a fire
-
resistance
-
rated assembly meeting the hour rating and, if app
licable, the impact
-
resistance rating required for the 
corridor or exit enclosure. Such assembly shall be rated for exposure to fire from both sides.
2.
In residential buildings that do not have floors below grade, or in multi
-
use buildings that have a res
i-
dential occupancy, gas
piping may be installed in public corridors in accordance with the following:
2.1.
Gas piping shall be permitted to be installed within a public corridor at the lowest level of the 
building or the lowest residential level of the bui
lding.
2.2.
All gas valves located within the public corridor shall be accessible for maintenance and inspec-
tion.
2.3.
Gas pressure within the public corridor piping shall not exceed 
1
/
2
psi (14 inch w.c.).
2.4.
The public corridor shall be ventilated in accordance with the 
New York City Mechanical Code
. 
The pipe shall not be installed in a return air plenum.
2.5.
Pipes must be welded.
404.4
Piping in solid partitions and walls.
Concealed piping shall not be locat
ed in solid partitions and solid walls, 
unless installed in a 
ventilated
chase or casing.
404.5 Fittings
in concealed locations.
Fittings
installed in concealed locations shall 
be limited to the following types:
1.
Threaded elbows, tees and 
couplings.
2.
Welded fittings.
404.6
Piping through foundation wall.
Underground piping
, where installed
below grade 
through the outer founda-
tion or basement wall of a building, shall be encased in a protective pipe sleeve.
Such sleeve
shall
extend a minim
um 
of 1 inch (25.4 mm) beyond the inside of the foundation wall
and
a minimum of 4 inches (101.6 mm) beyond the 
outside of the foundation wall, or as otherwise required by the gas provider.
The
annular space between the 
gas piping 
and the sleeve shall be
waterproofed
and
sealed.
404.7
Branch take
-
off.
Branches
shall be 
taken off the riser
with not less than a two
-
elbow swing.
404.8
Piping in solid floors.
Piping in solid floors shall be laid in channels in the floor and covered in a manner that 
will allow 
access to the piping with a minimum amount of damage to the building. Where such piping is subject to 
exposure to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. As an 
alternative to installation in channels
, the piping shall be installed in a conduit of Schedule 40 steel 
or
wrought iron 
pipe 
installed
in accordance with Section 404.8.1 or 404.8.2
.
404.8.1
Conduit with one end terminating outdoors.
The conduit shall extend into an occupiable portion of the 
bu
ilding and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend not less than 2 
inches (
50.8
mm) beyond th
e point where the pipe emerges from the floor. If the end sealing is capable of with-
standing the full pressure of the gas pipe, the conduit shall be designed for the same pressure as the pipe. Such 
GAS PIPING INSTALLATIONS
conduit shall extend not less than 4 inches (
101.6
mm) out
side the building, shall be vented above grade to the 
outdoors and shall be installed so as 
to
prevent the entrance of water and insects.
404.8.2
Conduit with both ends terminating indoors.
Where the conduit originates and terminates within the 
same buildi
ng, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from 
the floor.
404.9
Above
-
ground outdoor pip
ing.
Piping
installed outdoors shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) 
above ground and where installed across roof surfaces, shall be elevated not less than 
3
1
/
2
inches (
88.9
mm) above the 
roof surface
, identified in accordance with Section 401.5, and shall not be concealed
. Piping installed above ground, 
outdoors, and 
installed across the surface of roofs shall be securely supported to the structure and located where it will 
be protected from physical damage. Where passing through an outside wall, the piping 
shall be
protected against 
corrosion 
in accordance
with
Sectio
n 404.11
. Where piping is encased in a protective pipe sleeve, the annular space 
between the piping and the sleeve shall be sealed. 
At least one end shall have a vented outlet piped to a safe location 
outdoors. The vent terminal shall be outdoors, minimum 
18 inches (
457.2
mm) above grade, not under an opening to 
building or overhang, and shall be installed so as to prevent the entrance of water and insects.
404.10
Reserved.
404.11 Protection against corrosion.
Metallic pipe, fittings
, and joints 
susceptible
to corrosive action, such as soil 
condition or moisture, shall be protected in an approved manner 
as set forth in Sections 404.11.1 through 404.11.6.
404.11.1
Prohibited use.
Threaded or uncoated
welded joints shall not be used in piping in con
tact with soil. 
Uncoated piping, fittings, and joints shall be prohibited
where internal or external corrosion is known to occur.
404.11.2 Protection of exposed pipe.
Ferrous metal exposed in exterior locations shall be protected from corrosion 
by one of t
he following methods:
1.
Zinc coatings (galvanizing
).
2.
Bonded coatings in accordance with Section 404.11.4.
3.
Protective coatings in accordance with Section 404.11.5.
4.
Protective wrappings in accordance with Section 404.11.6. 
404.11.3 
Protection of buried pipe.
Ferrous metal installed in buried locations shall be protected from corrosion 
by one of the following methods:
1.
Bonded coatings in accordance with Section 404.11.4.
2.
Protective wrappings in accordance with Section 404.11.6.
W
here dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not 
be laid in contact with cinders.
404.11.4
.
Protective 
bonded
coatings.
Pipe protective 
bonded
coatings shall be approved for the application an
d 
shall be factory applied.
Exception:
Where installed in accordance with the manufacturer’s 
instructions
, field application of 
bonded
coatings shall be permitted for 
pipe,
fittings and locations where the factory coating or wrapping has been dam-
aged or ne
cessarily removed at joints.
404.11.5 Protective coatings.
Pipe protective coatings shall be approved for the application and shall be factory 
applied or field applied in accordance with the manufacturer’s instructions.
Exception:
Where installed in accord
ance with the manufacturer’s instructions, field application of coatings 
shall be permitted for pipe, fittings and locations where the factory coating has been damaged or necessarily 
removed at joints.
404.11.6 Protective wrappings.
Pipe protective wrappin
gs shall be approved for the application and shall be field 
applied in accordance with the manufacturer’s instructions.
GAS PIPING INSTALLATIONS
404.12
Minimum burial depth.
Underground piping systems shall be installed a minimum depth of 
24
inches (
609.6
mm) below grade
,
measured
to
the top of the pipe
.
Exception:
Burial depth less than 24 inches (609.6 mm) is permissible when the underground piping system is 
protected by steel protective plates not less than 
1
/
4
-
inch thick (6.36 mm) and with joints tack welded and over-
lap
ped a minimum of 3 inches (76.2 mm). The pipe shall be not less than 4 inches (101.6 mm) below the protective 
steel plate.
404.13
Trenches.
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the 
bottom of the trench
.
404.13.1 Backfilling.
Material used under and beside pipes shall be clean backfill, free of discarded construction 
material and debris. Loose earth free from rocks, broken concrete and frozen chunks shall be placed in the trench 
in 6
-
inch (152.4 mm) laye
rs and tamped in place until the crown of the pipe is covered by 12 inches (304.8 mm) 
of tamped earth. The backfill under and beside the pipe shall be compacted for pipe support. Backfill shall be 
brought up evenly on both sides of the pipe so that the pip
e remains aligned. In instances where the manufacturer’s 
installation instructions for materials are more restrictive than those prescribed by the code, the material shall be 
installed in accordance with the more restrictive requirement. Backfilling is sub
ject to progress inspection in ac-
cordance with Section 108.
404.14
Piping underground beneath buildings.
Piping installed underground beneath buildings is prohibited except 
where the piping is encased in a conduit of wrought iron 
or
steel pipe designed to 
withstand the superimposed loads. 
The conduit shall be protected from corrosion in accordance with Section 
404.11
and shall be installed in accordance 
with Section 
404.14.1
, 404.14.2
or 
404.14.
3
.
404.14.1
Conduit with one end terminating outdoors.
The cond
uit shall extend into an occupiable portion of the 
building and, at the point where the conduit terminates in the building, the space between the conduit and the gas 
piping shall be 
permanently
sealed to prevent the possible entrance of any gas leakage.
The conduit shall extend 
not less than 2 inches (
50.8
mm) beyond the point where the pipe emerges from the floor. 
The
end sealing 
shall be
capable of withstanding the full pressure of the gas pipe, 
and
the conduit shall be designed for the same pressure 
a
s the pipe. Such conduit shall extend not less than 4 inches (
101.6
mm) outside of the building, shall be vented 
above grade to the outdoors and shall be installed so as to prevent the entrance of water and insects.
404.
14.2
Conduit with both ends terminat
ing indoors.
Where the conduit originates and terminates within the 
same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be 
sealed.
The conduit shall extend not less than 2 inches (
50.8
mm) beyond 
the point where the pipe emerges from 
the floor.
404.14.3 Conduit with both ends terminating indoors within different buildings.
Where the conduit originates 
indoors in a building and terminates indoors within a different building, the conduit shall comply
with Section 
404.14.2.
‡‡‡
404.15
Outlet closures.
Gas outlets shall be 
permitted only under the following conditions:
1.
Valved and
capped gas tight 
outlets 
for appliance
outlets 
listed on
approved 
applications
.
2.
Valved and capped outlets on each 
floor in nonproduction laboratory buildings for future laboratories.
3.
Listed and labeled flush
-
mounted
-
type 
quick disconnect
devices and listed and labeled gas convenience outlets 
installed in accordance with the manufacturer’s 
instructions
.
Exceptions:
1.
Test ports for gas riser valves installed downstream of a riser control valve.
2.
Outlets for pressure sensors and gauges installed in conjunction with gas appliances or equipment in-
stalled in accordance with the manufacturer’s instructions.
404.16
Loca
tion of outlets.
The unthreaded portion of piping outlets shall extend not less than 
1
inch (
25
.4
mm) 
through finished ceilings and walls and where extending through floors or outdoor patios and slabs, shall 
be
not less 
than 2 inches (
50.8
mm) above them. 
The outlet fitting or piping shall be securely supported. Outlets shall not be 
placed behind doors. Outlets shall be located in the room or space where the appliance is installed.
GAS PIPING INSTALLATIONS
Exception:
Listed and labeled flush
-
mounted
-
type 
quick
-
disconnect
devices an
d listed and labeled gas conven-
ience outlets shall be installed in accordance with the manufacturer’s 
instructions
.
404.17
Reserved.
404.18 Pipe cleaning.
The use of a flammable or combustible gas to clean or remove debris from 
the interior of
a 
piping system shall be prohibited.
404.19
Prohibited devices.
A device shall not be placed inside the piping or fittings that will reduce the cross
-
sectional 
area or otherwise obstruct the free flow of gas.
Exceptions:
1.
Approved gas filters.
2.
An approved fitting or device where the gas piping system has been siz
ed to accommodate the pressure drop 
of the fitting or 
device
.
3.
Approved gas meters for monitoring and analysis of gas usage.
404.20
Testing of piping.
Before any system of piping is put in 
service,
it shall be tested to ensure that it is gas tight. 
Testi
ng, inspection and purging of piping systems shall comply with Section 406.
404.21 Qualifications for gas work.
Gas work shall be performed by individuals possessing the qualifications set 
forth in Article 28
-
423 of the 
Administrative Code
. Welders must be
qualified in accordance with Section 404.21.1.
404.21.1 Welder’s qualifications.
Welders installing gas piping within buildings at any pressure shall comply with 
the following:
1.
Welders shall be qualified for all pipe sizes, wall thicknesses and all pos
itions in accordance with the ASME 
Boiler and Pressure Vessel Code
, Section IX. Requalification of welders is required on an annual basis and when 
requested by the commissioner.
2.
Welder qualification testing shall be performed by an approved agency and t
he inspector witnessing the test 
shall be an authorized AWS Certified Welding Inspector. Radiographic test specimens shall be evaluated by 
a radiographic inspector having a minimum radiography qualification of Level II in accordance with the 
ASNT, Document
No. SNT
-
TC
-
1A, Supplement A.
3.
Copies of the certified welder qualification reports shall be maintained by both the approved agency and the 
licensed master plumber employing the welder(s) for at least six years and shall be made available to the 
department upon request.
4.
The approved agency shall submit certified welder qualification reports to the department upon successful 
qualification of a welder and when requested by the commissioner.
5.
The licensed master plumber employing the welder(s) s
hall submit a statement to the department including 
who welded the gas piping along with a copy(s) of the certified welder qualification report(s) witnessed by a 
representative of the licensed master plumber, at the time of the first roughing inspection.
6
.
Requalification of a welder is required should the welder fail to maintain welder’s continuity every six 
months. The licensed master plumber employing the welder shall maintain a welder continuity log and the 
log shall be made available to the department
upon request.
404.21.2 Welding requirements.
All gas distribution piping to customer appliances operating in excess of 
1
/
2
psig 
(3.5 kPa gauge) shall be welded.
404.21.3 Welding records.
The licensed master plumber employing the welder(s) shall assign to 
each welder an 
identification symbol or number to identify the welds performed by that particular welder. The welder shall identify 
all welds with his or her symbol or number. The licensed master plumber shall maintain records identifying the 
weld(s) made 
by each welder for at least six years and shall make such records available to the department upon 
request.
GAS PIPING INSTALLATIONS
‡‡‡
SECTION FGC 405
PIPING BENDS AND CHANGES IN DIRECTION
405.1 General.
Changes in direction of pipe shall be permitted to be made by the use of fi
ttings
, factory bends, or 
field bends.
405.2 
Metallic pipe.
Metallic pipe bends shall comply with the following:
1.
Bends shall be made only with bending tools and procedures intended for that purpose.
2.
All bends shall be smooth and free from 
buckling, cracks or other evidence of mechanical damage.
3.
Bends
shall be 
made only with seamless pipe
.
4.
Pipe shall not be bent through an arc of more than 90 degrees (1.6 rad).
5.
The inside radius of a bend shall be not less than six times the outside
diameter of the pipe.
405.3 
Reserved.
405.4 Elbows.
Factory
-
made welding elbows or transverse segments cut therefrom shall have an arc length measured 
along the crotch 
of not less than
1 inch (
25
.4
mm) in pipe sizes 2 inches (
50.8
mm) and larger.
SECTION FGC 406
INSPECTION, TESTING AND PURGING
406.1 General.
Prior to acceptance and initial operation, all piping installations shall be inspected and pressure tested 
to determine that the materials, design, 
fabrication and
installation practices comply
with the requirements of this 
code.
406.1.1 Inspections.
Inspection shall consist of visual 
examination during
or after manufacture, fabrication, 
as-
sembly or
pressure tests 
as appropriate. Supplementary types of nondestructive inspection techniques, such 
as mag-
netic
-
particle, radiographic, ultrasonic, etc., shall not be required unless specifically listed herein or in the engi-
neering design.
All inspections shall be performed in accordance with Section 108.
406.1.1.1
Welding inspections and 
testing.
Welded gas piping shall be subject to special inspection in accord-
ance with Chapter 17 of the 
New York City Building Code
. Radiographic testing shall be performed on all butt 
welds in gas meter and gas distribution piping operating at pressures ex
ceeding 5 psig (34.5 kPa gauge) within 
buildings, in accordance with ASME 
Boiler and Pressure Vessel Code
, Section IX.
406.1.2 Repairs and additions.
In the event repairs or additions are made after the pressure test, the affected 
piping shall be tested. 
A
ll sections of de
-
energized piping shall be pressure tested in accordance with Section 
406.4.
406.1.3 New branches.
Where new branches are installed, 
the
new branches shall be pressure tested. Connections 
between the new piping and the existing piping shal
l be 
pressure tested.
406.1.4 
Section
testing.
A piping system shall be 
permitted to be tested as a complete unit or in sections. Under 
no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and 
test medium in an adjacent section, except where a double block and bleed val
ve system 
or flange
is installed. A 
valve shall not be subjected to the test pressure unless 
the piping system upstream of
the valve 
has been deener-
gized. The section of piping not subjected
to the pressure 
test shall be checked with a noncorrosive leak
-
de
tecting 
fluid or other approved leak
-
detecting methods. Sections may be tested at different pressures in accordance with 
Section 406.4.
406.1.5 Regulators and valve assemblies.
Regulator and valve assemblies fabricated independently of the piping 
system in
which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. 
Such regulators and valve assemblies shall not be subjected to the testing requirements of Section 406.4. Spool 
pieces shall be installed in p
lace for the test. The regulators and valve assemblies not subjected to the pressure test 
shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods.
GAS PIPING INSTALLATIONS
406.1.6 Pipe clearing.
Prior to testing, the interior of the pipe 
shall be 
purged with air or an inert gas to clear 
foreign material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations 
or piping installation.
406.2 Test medium.
The test medium shall be air, nitrogen, carb
on dioxide or an inert gas. Oxygen shall not be used.
406.3 Test preparation.
Pipe joints 
and piping
including welds, shall be left exposed for examination during the test.
Exception:
Covered or concealed pipe end joints that have been previously 
inspected
in accordance with this code.
406.3.1 Expansion joints.
Expansion joints shall be provided with temporary restraints, if required, for the addi-
tional thrust load under test.
406.3.2 Appliance and equipment isolation.
Appliances and equipment that are not 
to be included in the test shall 
be either disconnected from the piping or isolated by blanks, blind 
flanges or
caps. Flanged joints at which blinds 
are inserted to blank off other equipment during the test shall not be required to be tested. 
The affected 
piping and 
joints shall be checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods when 
gas is energized.
406.3.3 Appliance and equipment disconnection.
Where the piping system is connected to appliances or equip-
ment desig
ned for operating pressures of less than the test pressure, such appliances or equipment shall be isolated 
from the piping system by disconnecting them and capping the outlet(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
dete
cting fluid or other approved leak
-
detecting methods when gas is energized.
406.3.4 Valve isolation.
Where the piping system is connected to appliances or equipment designed for operating 
pressures equal to or greater than the test pressure, such appliance
s or equipment shall be isolated from the piping 
system by closing the individual appliance or equipment shutoff valve(s). 
The affected piping and joints shall be 
checked with a noncorrosive leak
-
detecting fluid or other approved leak
-
detecting methods whe
n gas is energized.
406.3.5 Testing precautions.
Testing
of piping systems shall be 
performed in a manner that protects
the safety of 
employees and the public during the test. 
Bulkheads, anchorage, and bracing suitably designed to resist test 
pres-
sures shall be installed if necessary. Prior to testing, the interior of the pipe shall be purged to flush out all foreign 
material, including weld splatter, dirt, rags, and other debris left inside the pipe during welding operations and 
piping install
ation.
406.4 
Test pressure measurement.
Upon completion of the installation of a section of a gas system or of the entire 
gas system, and before appliances are connected thereto, the completed section or system shall be verified as to mate-
rials, and tested
and proven tight
.
Test pressure shall be measured with a manometer or with a pressure
-
measuring 
device designed and calibrated to read, record or indicate a pressure loss caused by leakage during the pressure test 
period. The source of pressure shall be i
solated before the pressure tests are made. Mechanical gauges used to measure 
test pressures shall have a range such that the highest end of the scale is not greater than 
two
times the test pressure
. 
Gauges shall comply with the requirements of Section 406
.4.3 or 406.4.4.
406.4.1 Test pressure.
The test pressure to be used shall be not less than 
1
1
/
2
times the proposed maximum working 
pressure, but not less than 3 psig (20
.9
kPa gauge), irrespective of design pressure. Where the test pressure exceeds 
125 ps
ig (
861.8
kPa gauge), the test pressure shall not exceed a value that produces a hoop stress in the piping 
greater than 50 percent of the specified minimum yield strength of the pipe.
Exceptions:
1.
Gas piping with distribution
pressures above 
5
psig (
34.5
kPa gauge) 
shall
be tested to twice the maximum 
allowable operating pressure, but not less than 100 psig (
689.5
kPa gauge), for a minimum of 1 hour.
2.
Gas piping installed in public corridors in accordance with Section 404 sh
all be tested and proven tight at 
a pressure of 10 psig (68.9 kPa gauge) for a minimum of 30 minutes. 
3.
Meter piping shall be pressure tested in accordance with the requirements of the serving utility. These 
requirements shall be either the same as those
for testing distribution piping 
in this
section or, if different, 
the piping shall be certified by the utility 
company
as being tested in compliance with their requirements.
4.
Notwithstanding the above, all 
field applied or
factory applied coated and wra
pped pipe shall be pressure 
tested at a minimum of 
100
psig (
689.5
kPa gauge) 
for a minimum of 60 minutes
. For testing, the piping 
GAS PIPING INSTALLATIONS
shall be filled with air or an inert gas, and the source of pressure shall be isolated before the pressure 
readings are made.
All test duration time periods are to be measured after stabilization of testing medium.
406.4.1.1 Factory applied coatings.
Gas piping with factory applied coatings intended to protect against cor-
rosion during material shipping and storage shall be teste
d at not less than 1
1
/
2
times the proposed maximum 
working pressure, but not less than 3 psig (20.9 kPa gauge), irrespective of design pressure. Where the test 
pressure exceeds 125 psig (861.8 kPa gauge), the test pressure shall not exceed a value that pro
duces a hoop 
stress in the piping greater than 50 percent of the specified minimum yield strength of the pipe.
406.4.1.2 Field applied paint.
Gas piping with field applied paint intended to protect against corrosion shall be 
tested at not less than 1
1
/
2
ti
mes the proposed maximum working pressure, but not less than 3 psig (20.9 kPa 
gauge), irrespective of design pressure. Where the test pressure exceeds 125 psig (861.8 kPa gauge), the test 
pressure shall not exceed a value that produces a hoop stress in the
piping greater than 50 percent of the specified 
minimum yield strength of the pipe.
406.4.2 Test duration.
Test duration shall be not less than 
1
/
2
hour, unless a greater duration is required by Section 
406.4.1.
406.4.3
Minimum standards 
for gauges
.
This section establishes minimum standards for gauges 
used
to test gas 
piping.
Each gauge shall meet the following requirements:
1.
The gauge shall be manufactured and used in accordance with ASME 
B40.100
, which incorporates ASME 
B40.1 and ASME B40.7, and the manufacturer shall provide with the gauge a written statement that the gauge 
is manufactured in accordance with such ASME standa
rd;
2.
The gauge shall be labeled with the name of the manufacturer;
3.
The units of measurement “psig” shall appear on the face of the gauge; and
4.
The gauge shall be kept in good working order.
406.4.4 Digital gauges used to measure pressure in the magn
itude of 3 psig (
20.9
kPa gauge) and higher.
Each 
digital gauge used to measure pressure in the magnitude of 3 psig (
20.9
kPa gauge) and higher shall meet the 
following requirements in addition to satisfying the minimum requirements set forth in Section 
40
6.4.3
:
1.
The gauge shall have a minimum reading of 
1
/
100
of a psig (69 Pa), and
2.
An extra charged battery shall be readily available for immediate use with the gauge.
‡‡‡
406.4.5 Witnessing tests of gas
piping systems.
Tests of gas piping systems in accordance with this code shall 
be witnessed by department plumbing 
inspectors.
‡‡‡
406.4.6 Conducting tests of gas
piping systems. 
Tests of gas piping systems in accordance with this code 
shall be conducted by an individual 
with not less than five years’ experience in gas work.
406.4.7
Notification.
The holder of the plumbing permit shall give at least two days 
prior notice
to the commis-
sioner that the plumbing work covered by the permit is ready for inspections and test.
406
.5 Detection of leaks and defects.
The piping system shall withstand the test pressure specified without showing 
any evidence of leakage or other defects. Any reduction of test pressures as indicated by pressure gauges shall be 
deemed to indicate the presence of a leak unless such reductio
n can be readily attributed to some other cause.
406.5.1 Detection methods.
The leakage shall be located by means of an approved gas detector, a noncorrosive 
leak detection 
fluid or
other approved leak detection methods.
406.5.2 Corrections.
Where leakage 
or other defects are located, the affected portion of the piping system shall be 
repaired or replaced and retested.
406.6 Piping system and equipment leakage check.
Leakage checking of systems and equipment shall be in accord-
ance with Sections 406.6.1 thro
ugh 406.6.4.
406.6.1 Check gases.
Leak checks using fuel gas shall be permitted in piping systems that have been pressure 
tested in accordance with Section 406.
GAS PIPING INSTALLATIONS
406.6.2 Before turning gas on.
During the process of turning gas on into a system of new gas pi
ping, the entire 
system shall be inspected to determine that there are no open fittings or ends and that all valves at unused outlets 
are closed and plugged or capped.
406.6.2.1 Gas authorization required.
A gas piping system shall not be energized prior t
o authorization. Such 
authorization is demonstrated by issuance of a certificate of approval of gas installation by the department. The 
certificate shall not be issued prior to the completion of the required inspections and tests. The certificate shall 
not
expire.
Exception:
Gas authorization shall not be required when gas is reestablished by a utility company as permit-
ted under Section 28
-
105.4.3 of Chapter 1 of Title 28 of the 
Administrative Code
.
406.6.2.1.1 Existing gas piping.
Any gas piping system or 
part thereof that has been previously energized 
and has been shut down shall be required to obtain a certificate of approval of gas installation for all appli-
ances served by the affected gas meter(s) prior to the reestablishment of gas into such system.
Ex
ception:
When an existing gas appliance is replaced and no gas piping is replaced upstream of the 
existing appliance shutoff valve and not more than 6 feet (1828.8 mm) of pipe is installed or replaced 
downstream of the existing appliance shutoff valve, a c
ertificate of approval of gas installation shall not 
be required to energize such pipe or replacement appliance.
406.6.2.1.2 Partial gas authorization.
A certificate of approval of gas installation may be issued for a por-
tion of a gas piping system provide
d the remainder of the system is locked
-
off by the gas service provider.
406.6.2.2
Establishing gas supply.
It shall be unlawful for any utility company to supply 
or restore
gas to a 
building, place or premises in which new meters other than replacement 
ga
s meters
are required until a certificate 
of approval of gas installation is 
issued in accordance with Section 406.6.2.1
. When new gas service piping has 
been 
installed, it
shall be locked
-
off by the utility either by locking the gas service line valve or 
by installing a 
locking device on the outside gas service line valve. The lock shall not be removed until the gas meter piping 
(other than utility
-
owned) and gas distribution piping has been inspected and certified as required by the depart-
ment as being re
ady for service. 
When an existing gas service piping has been taken out of service, it shall be 
locked
-
off by the utility. The lock shall not be removed until the gas meter piping (other than utility
-
owned) and 
gas distribution piping has been inspected an
d certified as required by the department as being ready for service.
406.6.2.3
Alterations to gas piping systems.
When alterations, extensions or repairs to existing gas meter pip-
ing or gas distribution piping requires the 
operation of a service head 
valve, regulator valve or meter valve that 
would interrupt the flow of gas to a building
, the utility shall be notified by the owner or his or her authorized 
representative.
406.6.2.4 Emergency service head valve, regulator valve or gas meter valve operati
on.
It is permissible for 
a licensed plumber or his or her employee to operate a valve in an emergency to alleviate a hazardous condition. 
The utility shall be notified by the licensee or his or her authorized representative. Such licensee or authorized 
re
presentative shall wait on location for utility company operators to arrive and lock the affected valve.
406.6.3 Leak check.
Immediately after the gas is turned on into a new system or into a system that has been initially 
restored after an interruption of
service, the piping system shall be checked for 
abnormal operating conditions and
leakage. 
The leakage check shall be performed by means of a combustible gas indicator complying with Section 
406.7.1.4, or a noncorrosive leak detection fluid.
Where leakage
is indicated,
or where an abnormal operating 
condition presents a hazard
,
the gas supply shall be shut off until the necessary repairs have been made.
406.6.4 Placing appliances and equipment in operation.
Appliances
and equipment shall 
not
be placed in o
per-
ation 
until
after the piping system has been 
checked in
accordance with Section 406.6.3
, the piping system has been
purged in accordance with Section 
406.7 and the connections to the appliances have been checked for leakage.
406.6.4.1 Requirements for p
lacing 
appliances
in operation.
The following will be required prior to placing 
appliances
in operation as applicable:
1.
Required fire protection system (sprinkler or standpipe) are completed, inspected and ready for service.
2.
Such 
appliance
and related 
equipment and
gas piping are inspected by the 
department
.
3.
Associated fire suppression system is inspected and approved by the Fire Department.
Exception:
Appliances may be used as temporary sources of heat during construction as needed and 
in ac-
cordance with requirements of the department.
GAS PIPING INSTALLATIONS
406.7 Purging.
The purging of piping shall be in accordance with Sections 406.7.1 through 406.7.3.
406.7.1 Piping systems required to be purged outdoors.
The purging of piping systems shall be in accordanc
e 
with the provisions of Sections 406.7.1.1 through 406.7.1.4 where the piping system meets either of the following:
1.
The design operating gas pressure is greater than 2 psig (
13.
8
kPa).
2.
The piping being purged contains one or more sections of pipe 
me
eting
the size and length criteria of Table 
406.7.1.1.
406.7.1.1 Removal from service.
Where existing gas piping is opened, the section that is opened shall be iso-
lated from the gas supply and the line pressure vented in accordance with Section 406.7.1.3. 
Where gas piping 
meeting the criteria of Table 406.7.1.1 is removed from service, the residual fuel gas in the piping shall be 
displaced with an inert gas.
TABLE 406.7.1.1
SIZE AND LENGTH OF PIPING
NOMINAL PIPE SIZE (inches)
LENGTH OF PIPING (feet)
≥
2
1
/
2
<
3
≥
50
≥
3 < 4
≥
30
≥
4 < 6
≥
15
≥
6 < 8
≥
10
≥
8
Any length
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
406.7.1.2 Placing in operation.
Where gas piping containing air and meeting the criteria of Table 406.7.1.1 is 
placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be 
displaced with fuel gas in accordance with Section 406.7.1.3.
406.7.1.3 Outdoor discharge of purged gases.
The open end of a piping system being pressure vented or 
purged shall discharge directly to an outdoor location. Purging operations shall comply with all of the following 
requirements:
1.
The point of discharge
shall be controlled with a shutoff valve.
2.
The point of discharge shall be located 
not less than
10 feet (3048 mm) from sources of ignition, 
not less 
than
10 feet (3048 mm) from building openings and 
not less than
25 feet (7620 mm) from mechanical air 
i
ntake openings.
3.
During discharge, the open point of discharge shall be continuously attended and monitored with a com-
bustible gas indicator that complies with Section 406.7.1.4.
4.
Purging operations introducing fuel gas shall be stopped when 
at least 95
percent fuel gas by volume is 
detected within the pipe.
5.
Persons not involved in the purging operations shall be evacuated from all areas within 10 feet (3048 mm) 
of the point of d
ischarge.
406.7.1.4 Combustible gas indicator.
Combustible gas indicators shall be listed and shall be calibrated in ac-
cordance with the manufacturer’s instructions. Combustible gas indicators shall numerically display a volume 
scale from zero percent to 1
00 percent in 1 percent or smaller increments.
406.7.2 Piping systems allowed to be purged indoors or outdoors.
The purging of piping systems shall be in 
accordance with the provisions of Section 406.7.2.1 where the piping system meets both of the followin
g:
1.
The design operating gas pressure is 2 psig (13.79 kPa) or less.
2.
The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria 
of Table 406.7.1.1.
406.7.2.1 Purging procedure.
The piping system shall 
be purged in accordance with one or more of the fol-
lowing:
GAS PIPING INSTALLATIONS
1.
The piping shall be purged with fuel gas that is discharged to the indoors or outdoors, and the point of 
discharge shall be monitored with a listed combustible 
gas
detector in accordance with Se
ction 406.7.2.2. 
Purging shall be stopped when fuel gas is detected. 
2.
The piping shall be 
purged in
accordance with written procedures 
of the utility company
.
406.7.2.2 Combustible gas detector.
Combustible gas detectors shall be listed and shall be cal
ibrated or tested 
in accordance with the manufacturer’s instructions. Combustible gas detectors shall be capable of indicating the 
presence of fuel gas.
406.7.3 Purging appliances and equipment.
After the piping system has been placed in operation, applian
ces and 
equipment 
subsequently installed
shall be purged before being placed into operation.
SECTION FGC 407
PIPING SUPPORT
407.1 General.
Piping shall be provided with support in accordance with Section 407.2. 
In addition, when earth-
quake loads are applicable in accordance with the 
New York City Building Code
, a detailed piping system stress 
analysis including seismic analysis shall be performed. The pipe supports and restraints shall be designed and 
installed t
o accommodate the resultant seismic forces, moments and displacements from this stress analysis in 
accordance with the 
New York City Building Code
.
407.2 Design and installation.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal ban
ds, 
metal brackets, metal hangers or building structural components, suitable for the size of piping, of adequate strength 
and quality, and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to 
prevent undue str
ains on connected appliances and shall not be supported by other piping. Pipe hangers and supports 
shall conform to the requirements of MSS SP
-
58 and shall be spaced in accordance with Section 415. Supports, 
hangers and
anchors shall be installed so as not
to interfere with the free expansion and contraction of the piping 
between anchors. All parts of the supporting equipment shall be designed and installed so 
that
they will not be 
disengaged by movement of the supported piping.
SECTION FGC 408
DRIPS AND SL
OPED PIPING
408.1 Slopes.
Piping for other than dry gas conditions shall be sloped not less than 
1
/
4
inch in 15 feet (6.3 mm in 4572 
mm) to prevent traps. The 
local
gas 
supplier/utility company should
be 
consulted to determine
the 
type
of 
fuel gas 
available for
the 
intended service
.
408.2 Drips.
Drips are not permitted.
408.3 
Test fittings.
A manufactured test fitting shall be installed where required by the gas supplier. Such fitting shall 
be downstream of a lockable supply or riser valve in accord
ance with the requirements of the gas supplier and the 
manufacturer’s instructions. The outlet of the test fitting shall be the smallest commercially available. The installation 
of manufactured test fittings in other locations shall be prohibited.
408.4 Se
diment trap.
Where a sediment trap is not incorporated as part of the appliance, a sediment trap shall be 
installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical. The sediment 
trap shall be either a tee fitti
ng having a capped nipple of any length installed vertically in the 
bottom most
opening 
of the tee 
as illustrated in Figure 408.4
or other device approved as an effective sediment trap. Illuminating appli-
ances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas 
fireplaces and
outdoor grills need not be so equipped.
GAS PIPING INSTALLATIONS
FIGURE 408.4
METHOD O
F INSTALLING A TEE FITTING SEDIMENT TRAP
SECTION FGC 409
SHUTOFF VALVES
409.1 General.
Piping systems shall be provided with shutoff valves in accordance with this section.
409.1.1 Valve approval.
Shutoff valves shall be of an approved type; shall be const
ructed of materials compatible 
with the piping; and shall comply with the standard that is applicable for the pressure and application, in accordance 
with Table 409.1.1.
TABLE 409.1.1
MANUAL GAS VALVE STANDARDS
VALVE STANDARDS
APPLIANCE SHUTOFF
VALVE APPLICATION UP
TO 
1
/
2
psig PRESSURE
OTHER VALVE APPLICATIONS
UP TO 
1
/
2
psig
PRESSURE
UP TO 2 psig
PRESSURE
UP TO 5 psig
PRESSURE
UP TO 125 psig
PRESSURE
ANSI Z21.15
/
CGA 9.1
X
—
—
—
—
ASME B16.44
X
X
X
a
X
b
—
ASME B16.33
X
X
X
X
X
For SI: 1 
pound per square inch gauge = 6.895 kPa.
a.
If labeled 2G.
b.
If labeled 5G.
GAS PIPING INSTALLATIONS
409.1.2 Prohibited locations.
Shutoff valves shall be prohibited in concealed locations and furnace plenums.
409.1.3 Access to shutoff valves.
Shutoff valves shall be located in 
places so as to provide access for operation 
and shall be installed so as to be protected from damage.
409.2 Meter valve.
Every meter shall be equipped with a shutoff valve located on the supply side of the meter. 
Meter 
valves shall be of a type approved b
y the utility company.
409.3 Shutoff valves for multiple
-
house line systems.
Where a single meter is used to supply gas to more than one 
building or tenant, a separate shutoff valve shall be provided for each building or tenant.
409.3.1 Multiple 
tenant buildings.
In multiple tenant buildings, where a common piping system is installed to 
supply other than 
individual dwelling units,
shutoff valves shall be provided for each tenant. Each tenant shall have 
access to the shutoff valve serving that tena
nt’s space.
409.3.2 Individual buildings.
In a common system serving more than one building, shutoff valves shall be 
installed outdoors at each building.
409.3.3 Identification of shutoff valves.
Each house line shutoff valve shall be plainly marked with a
n iden-
tification tag attached by the installer so that the piping systems supplied by such valves are readily identified. 
Identification shall be provided in compliance with ASME A13.1.
409.4 MP regulator valves.
An approved
shutoff valve shall be installe
d immediately ahead of each MP regulator.
409.5 Appliance shutoff valve.
Each appliance shall be provided with a shutoff valve in accordance with Section 
409.5.1 
or
409.5.
2
.
409.5.1 Located within 
the
same room.
The shutoff valve shall be located in the same room as the appliance. The 
shutoff valve shall be within 6 feet (
1828.8
mm) of the appliance, and shall be installed upstream of the union, 
connector or quick disconnect device it serves. Such shutoff valves 
shall be provided with access 
and located not 
more than 60 inches (1524 mm) above the finished floor
. Appliance shutoff valves located in the firebox of a 
fireplace shall be installed in accordance with the appliance manufacturer’s instructions. 
Where the 
shutoff valve 
is located in the firebox
, a
remote shutoff valve shall also be 
provided.
Exception:
Shutoff valves may be located more than 60 inches (1524 mm) above the finished floor where the 
gas connection to the appliance is more than 60 inches (1524 m
m) above the finished floor.
409.5.2 Vented decorative appliances and room heaters.
Shutoff valves for vented decorative appliances, room 
heaters and decorative appliances for installation in vented fireplaces shall be permitted to be installed in an area 
remote from the appliances where such valves are provided with ready access. Such valves shall be permanently 
identified and shall 
not
serve 
another
appliance. The piping from the shutoff valve to within 6 feet (
1828.8
mm) of 
the appliance shall be designe
d, sized and installed in accordance with Sections 401 through 408.
409.6 Shutoff valve for laboratories.
Where provided with two or more fuel gas outlets, including table
-
, bench
-
and 
hood
-
mounted outlets, each laboratory space in educational, research, commercial and industrial occupancies shall be 
provided with a single dedicated shutoff valve through whic
h all such gas outlets shall be supplied. The dedicated 
shutoff valve shall be readily accessible, located within the laboratory space served, located adjacent to the egress 
door from the space and shall be identified by approved signage stating “Gas Shuto
ff.”
409.7 Outside gas cut
-
off.
An outside gas service line valve or other outside shutoff device or method acceptable to 
the commissioner shall be provided in accordance with Section E.2 of Appendix 
E.
409.8 Riser shutoff valves.
Risers shall be equipped 
with an approved lockable shutoff valve. There shall be a test 
port installed downstream of the valve.
409.9 Branch shutoff valves.
Branches serving more than one appliance shall be equipped with an approved lockable 
shutoff valve. There shall be a test port installed downstream of the valve.
SECTION FGC 410
FLOW CONTROLS
GAS PIPING INSTALLATIONS
410.1 Pressure regulators.
A line pressure regulator shall be i
nstalled where the appliance is designed to operate 
at a lower pressure than the supply pressure. Line gas pressure regulators shall be listed as complying with ANSI 
Z21.80
/CSA 6.22
. Access shall be provided to pressure regulators. Pressure regulators shal
l be protected from 
physical damage. Regulators installed on the exterior of the building shall be approved for outdoor installation.
410.2 MP regulators.
Medium
pressure 
(MP)
regulators shall comply with the following:
1.
The MP regulator shall be approve
d and shall be suitable for the inlet and outlet gas pressures for the application.
2.
The MP regulator shall maintain a reduced outlet pressure under 
lockup
(no
-
flow) conditions.
3.
The capacity of the MP regulator, determined by published ratings of its 
manufacturer, shall be adequate to 
supply the appliances served.
4.
The MP regulator shall be provided with access. Where located indoors, the regulator shall be vented to the 
outdoors or shall be equipped with a 
leak
-
limiting
device, in either case comply
ing with Section 410.3.
5.
A tee fitting with one opening capped or plugged shall be installed between the MP regulator and its upstream 
shutoff valve. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring instrument and to 
serve
as a sediment trap.
6.
A tee fitting with one opening capped or plugged shall be installed not less than 10 pipe diameters downstream 
of the MP regulator outlet. Such tee fitting shall be positioned to allow connection of a pressure
-
measuring 
instrument. 
A pressure gauge with an isolation valve may also be installed in addition to the fitting.
7.
At least one union shall be installed within 1 foot (304.8 mm) of either side of the MP regulator.
410.3 Venting of regulators.
Pressure regulators that require a
vent shall be vented directly to the outdoors. The 
vent terminal shall be a minimum of 18 inches (
457.2
mm) above grade, not under 
a building
-
opening
or overhang, 
and shall be installed so as to prevent the entrance of water and insects.
Exception:
A vent to the outdoors is not required for 
regulators equipped
with and labeled for utilization with 
an
approved vent
-
limiting 
device
installed in accordanc
e with 
ANSI Z21.18 and
the manufacturer’s instructions. 
The 
vent
-
limiting device shall be installed in a location sufficiently ventilated to dissipate any gas discharged from 
the device.
410.3.1 Vent piping.
Vent piping for relief vents and breather vents 
shall be constructed of materials allowed for 
gas piping in accordance with Section 403. Vent piping shall be not smaller than the vent connection on the 
pres-
sure
-
regulating
device. Vent piping serving relief vents and combination relief and breather vents
shall be run 
independently to the outdoors and shall serve only a single device vent. Vent piping serving only breather vents is 
permitted to be connected in a manifold arrangement where sized in accordance with an approved design that 
minimizes 
back pres
sure
in the event of diaphragm rupture. Regulator vent piping shall not exceed the length 
specified in the 
regulator
manufacturer’s 
instructions
.
410.4 
Excess flow valves.
Where automatic excess flow valves are installed, they shall be listed for the application 
and shall be sized and installed in accordance with the manufacturer’s instructions.
410.5
Flashback arrestor check valve.
Where fuel gas is used with oxygen in any
hot work operation, a listed pro-
tective device that serves as a combination flashback arrestor and backflow check valve shall be installed at an ap-
proved location on both the fuel gas and oxygen supply lines. Where the pressure of the piped fuel gas suppl
y is 
insufficient to ensure such safe operation, approved equipment shall be installed between the gas meter and the appli-
ance that increases pressure to the level required for such safe operation.
SECTION FGC 411
APPLIANCE AND MANUFACTURED 
HOME
CONNECTIO
NS
411.1 Connecting appliances.
Except as required by Section 411.1.1, appliances shall be connected to the piping 
system by one of the following:
GAS PIPING INSTALLATIONS
1.
Rigid metallic pipe and fittings. 
Space heaters and water 
heaters shall
be connected using rigid piping an
d fittings 
only. Use of semirigid (flexible)
metallic tubing, fittings
, appliance
connectors 
or quick
-
disconnect devices is
not 
permitted for this application.
2.
Listed and labeled appliance connectors in compliance with ANSI Z21.24
/CGA 6.10
and installed
in accordance 
with the manufacturer’s 
instructions
and located entirely in the same room as the appliance. 
Connectors shall 
have an overall length not to exceed 6 feet (1828.8 mm). Measurement shall be made along the centerline of the 
connector. Only one 
connector shall be used for each appliance.
3.
Listed and labeled quick
-
disconnect devices used in conjunction with listed and labeled appliance connectors.
4.
Listed and labeled convenience outlets used in conjunction with listed and labeled appliance con
nectors.
5.
Listed and labeled outdoor appliance connectors 
in compliance
with ANSI Z21.75/CSA 6.27 and installed in 
accordance with the manufacturer’s 
instructions
.
6.
Listed outdoor gas hose connectors in compliance with ANSI Z21.54 used to connect porta
ble outdoor appli-
ances. The gas hose connection shall be made only in the outdoor area where the appliance is used, and shall be 
to the gas piping supply at an appliance shutoff valve, a listed quick
-
disconnect device or listed gas convenience 
outlet.
411.
1.1 Commercial cooking appliances.
Commercial cooking appliances installed on casters and appliances that 
are moved for cleaning and sanitation purposes shall be connected to the piping system with an appliance connector 
listed as complying with ANSI Z21.6
9
/CSA 6.16
and NSF/ANSI 169 or in accordance with Item 1 of Section 
411.1.
The commercial cooking appliance connector installation shall be configured in accordance with the manu-
facturer’s instructions. Movement of appliances with casters shall be limited 
by a restraining device installed in 
accordance with the connector and appliance manufacturer’s instructions.
411.1.2 Protection against damage.
Connectors and tubing shall be installed so as to be protected against physical 
damage.
411.1.3 Connector installation.
Fuel
connectors shall be installed in accordance with the manufacturer’s instruc-
tions and Sections 411.1.3.1 through 411.1.3.4.
411.1.3
.1 Maximum length.
Connectors shall have an overall length not to exceed 6 feet (
1828.8
mm). Meas-
urement shall be made along the centerline of the connector. Only one connector shall be used for each appli-
ance.
411.1.3.2 Minimum size.
Connectors shall have
the capacity for the total demand of the connected appliance.
411.1.3.3 Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended 
through, walls, floors, partitions, ceilings or appliance housings.
Exceptions:
1.
Connect
ors constructed of materials allowed for piping systems in accordance with Section 403 shall 
be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with 
Section 409.5.2.
2.
Rigid steel pipe connectors shall be per
mitted to extend through openings in appliance housings.
3.
Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in ac-
cordance with the listing of the appliance.
4.
Listed
connectors shall be permitted to extend t
hrough an opening in an appliance housing, cabinet or 
casing where the tubing or connector is protected against damage.
411.1.3.4 Shutoff valve.
A shutoff valve not less than the nominal size of the 
piping system
shall be installed 
ahead of the connector i
n accordance with Section 409.5.
411.1.4 Movable appliances.
Where appliances are equipped with casters or are otherwise subject to periodic 
movement or relocation for purposes such as routine cleaning and maintenance, such appliances shall be connected 
to
the supply system piping by means of 
an appliance connector listed as complying with ANSI Z21.69
/CSA 6.16
or by means of Item 1 of Section 411.1 
of this code
. Such flexible connectors shall be installed and protected against 
physical damage in accordance 
with the manufacturer’s 
instructions
.
GAS PIPING INSTALLATIONS
411.1.5 Connection of gas engine
-
powered air conditioners.
Internal combustion engines shall not be rigidly 
connected to the gas supply piping.
411.1.6 Unions.
A union fitting shall be provided for appliances connected
by rigid metallic pipe. Such unions 
shall be accessible and located within 6 feet (
1828.8
mm) of the appliance.
411.2 Manufactured home connections.
Manufactured homes shall be connected to the distribution piping system 
by one of the following materials:
1.
Metallic pipe in accordance with Section 403.4.
2.
Listed and labeled connectors in compliance with ANSI Z21.75/CSA 6.27 and installed in accordance with the 
manufacturer’s 
instructions
.
411.3 Suspended low
-
intensity infrared tube heaters.
Suspended lo
w
-
intensity infrared tube heaters shall be con-
nected to the building piping system with a connector listed for the application complying with ANSI Z21.24/CGA 
6.10. The connector shall be installed as specified by the tube heater manufacturer’s instructions
.
SECTION FGC 412
LIQUEFIED PETROLEUM GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
412.1 
Applicability.
Motor fuel
-
dispensing facilities for LP
-
gas fuel shall be 
designed and operated
in accordance with the 
New York City
Fire Code
.
412.2 Reserved.
412.3 Reserved.
412.4 Reserved.
412.5 Reserved.
412.6 Reserved.
412.7 Reserved.
412.8 Reserved.
SECTION FGC 413
COMPRESSED NATURAL GAS MOTOR VEHICLE
FUEL
-
DISPENSING 
FACILITIES
413.1 Applicability.
Motor fuel
-
dispensing facilities for CNG fuel shall be 
designed and operated
in accordance with 
the 
New York City
Fire Code
.
413.2 Reserved.
413.3 Reserved.
413.4 Reserved.
413.5 Reserved.
413.6 Reserved.
413.7 Reserved.
413.8 Reserved.
SECTION FGC 414
RE
SERVED
GAS PIPING INSTALLATIONS
SECTION FGC 415
PIPING SUPPORT INTERVALS
415.1 Interval of support.
Piping shall be supported at intervals not exceeding the spacing specified in Table 415.1.
TABLE 415.1
SUPPORT OF PIPING
STEEL PIPE, NOMINAL SIZE OF PIPE
(inches)
SPACING OF 
SUPPORTS
(feet)
1
/
2
6
3
/
4
or 1
8
1
1
/
4
or larger (horizontal)
12
All vertical piping
Every floor level
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
SECTION FGC 416
OVERPRESSURE PROTECTION DEVICES
416.1 
Where required.
Where the serving gas supplier delivers gas at a pressure greater than 2 psi 
(13.79 kPa)
for 
piping systems serving appliances designed to operate at a gas pressure of 14 inches w.c. 
(3.49 kPa)
or less, overpres-
sure protection devices shall be installed. 
Piping systems serving 
appliances
designed to operate at inlet pressures 
greater than 14 inches w.c. 
(3.49 kPa)
shall be equipped with overpressure protection devices as required by the ap-
pliance manufacturer’s instructions.
416.2 
Pressure limitation requi
rements.
The requirements for pressure limitation shall be in accordance with Sec-
tions 416.2.1 through 416.2.5.
416.2.1 Pressure under 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure of 14 inches w.c. 
(3.49 kPa)
or less are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to
limit the gas pressure to each connected 
appliance to 2 psi or less upon a failure of the line pressure regulator.
416.2.2 Pressure over 14 inches w.c.
Where piping systems serving appliances designed to operate with a gas 
supply pressure greater than 14 
inches w.c. 
(3.49 kPa)
are required to be equipped with overpressure protection by 
Section 416.1, each overpressure protection device shall be adjusted to limit the gas pressure to each connected 
appliance as required by the appliance manufacturer’s instru
ctions. 
416.2.3 Device capability.
Each overpressure protection device installed to meet the requirements of this section 
shall be capable of limiting the pressure to its connected appliance(s) as required by Section 416.2.1, independently 
of any other pr
essure control equipment in the piping system.
416.2.4 Failure detection.
Each gas piping system for which an overpressure protection device is required by 
Section 416 shall be designed and installed so that a failure of the primary pressure control device
(s) is detectable. 
416.2.5 Relief valve.
Where a pressure relief valve is used to meet the requirements of Section 416, it shall have a 
flow capacity such that the pressure in the protected system is maintained at or below the limits specified in Section 
416.2.1 under all of the following conditions:
1.
The line pressure regulator for which the relief valve is providing overpressure protection has failed wide 
open.
2.
The gas pressure at the inlet of the line pressure regulator for which the relief valve i
s providing overpressure 
protection is not less than the regulator’s normal operating inlet pressure.
GAS PIPING INSTALLATIONS
416.3
Devices.
Pressure
-
relieving or pressure
-
limiting devices shall be one of the following:
1.
Pressure relief valve.
2.
Monitoring regulator.
3.
Series
regulator installed 
upstream from the
line regulator 
and set to continuously limit the pressure on the inlet 
of the line regulator to the maximum values specified by Section 416.2.1.
4.
Automatic
shutoff device installed in series with 
the line
pressure r
egulator and set to shut off when the pressure 
on the downstream piping system reaches the maximum 
values specified by Section 416.2.1.
This device shall 
be designed so that it will remain closed until manually reset.
The devices 
specified in this section
shall be installed either as an integral part of the service or line pressure 
regulator or as separate units. Where separate pressure
-
relieving or pressure
-
limiting devices are installed, they shall 
comply with Sections 
416.3.1
through 
416.3.6
.
416.3.1
Con
struction and installation.
Pressure
-
relieving
and pressure
-
limiting devices shall be constructed of 
materials so that the operation of the devices will not be impaired by corrosion of external parts by the atmosphere 
or of internal parts by the gas. Press
ure
-
relieving and pressure
-
limiting devices shall be designed and installed so 
that they can be operated to determine whether the valve is free. The devices 
shall be
designed and installed so that 
they can be tested to determine the pressure at which they 
will operate and examined for leakage when in the closed 
position. 
The devices shall be maintained and inspected in accordance with Section 416.3.7.
416.3.2
External control piping.
External control piping shall 
be designed
and installed so that damage to 
the
control piping 
of one device
will not render both the regulator and the overpressure 
protection
device inoperative.
416.3.3
Setting.
Each pressure
-
relieving or pressure
-
limiting device shall be set so that the 
gas
pressure 
supplied 
to
the connected appliances 
does not exceed the limits specified in Section 416.2.1
.
416.3.4
Unauthorized operation.
Precautions shall be taken to prevent
u
nauthorized operation of any shutoff 
valve 
that will make
a 
pressure
-
relieving
valve or pressure
-
limiting device inoperative. The valve shall be locked 
or
continuously monitored
in the open position.
416.3.5
Vents.
The discharge stacks, vents and outlet pa
rts of all pressure
-
relieving and pressure
-
limiting devices 
shall be located so that gas is safely discharged to the outdoors. Discharge stacks and vents shall be designed to 
prevent the entry of water, insects and other foreign material that could cause b
lockage. The discharge stack or vent 
line shall be 
not less than
the same size as the outlet of the pressure
-
relieving device.
416.3.6
Size of fittings, pipe and openings.
The fittings, pipe and openings located between the system to be 
protected and the p
ressure
-
relieving device shall be sized to prevent hammering of the valve and to prevent impair-
ment of relief capacity.
416.3.7 Device maintenance.
The overpressure protection device: (i) shall be properly maintained and inspected 
every two years by a lice
nsed master plumber; (ii) inspection records shall be maintained by the owner and made 
available to the department; (iii) inspection procedures shall be in accordance with the commissioner; and (iv) 
replacements or repairs shall be promptly made.
Exception
:
Where the gas pressure is 15 psig (103.4 kPa gauge) or above, the overpressure protection device 
shall be inspected annually.