‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
BOILERS, WATER HEATERS AND PRESSURE VESSELS
4.2.
UL 2106.
Exception:
Unlisted equipment shall obtain approval from the department.
5.
Controls and safety devices shall be tested and inspected in accordance with ASME CSD
-
1 and, as applicable, 
the 
ASME Boiler and Pressure Vessel Code
,
12 NYCRR Parts 4 and 14, and NFPA 85. Testing and inspection 
shall be performed by the burner manufacturer’s authorized representative in the presence of the licensed 
installer. 
6.
Inspection of the installed boiler assembly shall be performed by the dep
artment.
1004.2 Installation.
In addition to the requirements of this code, the installation of boilers shall conform to the 
man-
ufacturer’s
instructions. Operating instructions of a permanent type shall be 
located in
the boiler
room and readily 
accessible
.
Boilers shall have all controls set, adjusted and tested by the installer. The manufacturer’s rating data and 
the nameplate shall be attached to the boiler.
1004.3 Working clearance.
Clearances shall be maintained around boilers, generators, heaters, tanks and related 
equipment and appliances so as to permit inspection, servicing, repair, replacement and visibility of all gauges. When 
boilers are installed or replaced, clearance shall 
be provided to allow access for maintenance and repair
per the boiler’s 
listing and manufacturer’s instructions.
Passageways 
for inspection 
around all sides of boilers shall have an unob-
structed width of not less than 18 inches 
(
457.2
mm) 
unless 
the boiler
’s listing or department approval or manufac-
turer’s instructions state 
otherwise.
1004.3.1 Top clearance.
Clearances from the tops of boilers to the ceiling or other overhead obstruction shall be 
in accordance with Table 1004.3.1.
TABLE 1004.3.1
BOILER TOP
CLEARANCES
BOILER TYPE
MINIMUM 
CLEARANCES FROM 
TOP OF BOILER TO 
CEILING OR OTHER 
OVERHEAD 
OBSTRUCTION (feet)
All boilers with manholes on top of the 
boiler except where a greater clearance is 
required in this table.
3
All boilers without 
manholes on top of 
the boiler except high
-
pressure steam 
boilers and where a greater clearance is 
required in this table.
2
High
-
pressure steam boilers with steam 
generating capacity not exceeding 5,000 
pounds per hour.
3
High
-
pressure steam 
boilers with steam 
generating capacity exceeding 5,000 
pounds per hour.
7
High
-
pressure steam boilers having heat-
ing surface not exceeding 1,000 square 
feet.
3
High
-
pressure steam boilers having heat-
ing surface in excess of 1,000 square 
feet.
7
High
-
pressure steam boilers with input 
not exceeding 5,000,000 Btu/h.
3
BOILERS, WATER HEATERS AND PRESSURE VESSELS
High
-
pressure steam boilers with input in 
excess of 5,000,000 Btu/h.
7
Steam
-
heating boilers and hot water
-
heating boilers with input exceeding 
5,000,000 Btu/h.
3
Steam
-
heating boilers exceeding 5,000 
pounds of steam per hour.
3
Steam
-
heating boilers and hot water
-
heating boilers having heating surface 
exceeding 1,000 square feet.
3
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m
2
, 1 pound per hour = 0.4536
kg/h, 1 Btu/hr = 0.293 W.
1004.4 Mounting.
Equipment
and appliances
shall be set or mounted on a level base capable of supporting and dis-
tributing the weight contained thereon. Boilers, tanks and equipment shall be 
securely anchored to the structure. 
Equ
ipment and appliances requiring vibration isolation shall be installed as designed by a registered design profes-
sional
in accordance with the manufacturer’s instructions.
1004.5 Floors.
Boilers shall be mounted on floors of noncombustible 
construction, unless listed for mounting on 
combustible flooring. Vibration isolation shall be in accordance with Section 313. In buildings with residential occu-
pancies, boilers shall be installed in accordance with the requirements of Section 313.
1004.6 
Boiler rooms and enclosures.
Boiler rooms and enclosures and access thereto shall comply with Chapters 5 
and 10 of the 
New York City 
Building Code
and Chapter 3 of this code. Boiler rooms shall be equipped with a floor 
drain or other approved means for 
disposing
of liquid waste
in accordance with the 
New York City Plumbing Code
.
1004.7 Operating adjustments and instructions.
Hot water and steam boil
ers shall have all operating and safety 
controls set and operationally tested by the installing contractor. A 
complete
control diagram and boiler operating 
instructions shall be furnished by the installer for each installation.
A complete control diagram o
f a permanent type 
shall be located in the boiler room and shall be readily accessible.
1004.8 Burner controls.
Gas and oil modulating burners shall be provided with burner controls (oil and gas equiv-
alent ratings) in accordance with ASME CSD
-
1 and NFPA 85
.
1004.9 Conversion burners. 
Conversion burners shall be installed in accordance with ANSI Z21.8.
SECTION MC 1005
BOILER CONNECTIONS
1005.1 Valves.
Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple 
boil
er or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in 
the 
supply
and return piping.
Exception: 
Shutoff valves are not required in a system 
having
a single low
-
pressure steam boiler
of 350,000 Btu
/h 
(103 kW) output or less
.
1005.2 Potable water supply.
The water supply to all boilers, including but not limited to backflow prevention, shall 
be connected in accordance with the 
New
York City 
Plumbing Code
. 
SECTION MC 1006
SAFETY AND PRESSURE 
RELIEF VALVES
AND CONTROLS
1006.1 Safety valves for steam boilers. 
Steam boilers shall be protected with a safety valve 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
BOILERS, WATER HEATERS AND PRESSURE VESSELS
4.2.
UL 2106.
Exception:
Unlisted equipment shall obtain approval from the department.
5.
Controls and safety devices shall be tested and inspected in accordance with ASME CSD
-
1 and, as applicable, 
the 
ASME Boiler and Pressure Vessel Code
,
12 NYCRR Parts 4 and 14, and NFPA 85. Testing and inspection 
shall be performed by the burner manufacturer’s authorized representative in the presence of the licensed 
installer. 
6.
Inspection of the installed boiler assembly shall be performed by the dep
artment.
1004.2 Installation.
In addition to the requirements of this code, the installation of boilers shall conform to the 
man-
ufacturer’s
instructions. Operating instructions of a permanent type shall be 
located in
the boiler
room and readily 
accessible
.
Boilers shall have all controls set, adjusted and tested by the installer. The manufacturer’s rating data and 
the nameplate shall be attached to the boiler.
1004.3 Working clearance.
Clearances shall be maintained around boilers, generators, heaters, tanks and related 
equipment and appliances so as to permit inspection, servicing, repair, replacement and visibility of all gauges. When 
boilers are installed or replaced, clearance shall 
be provided to allow access for maintenance and repair
per the boiler’s 
listing and manufacturer’s instructions.
Passageways 
for inspection 
around all sides of boilers shall have an unob-
structed width of not less than 18 inches 
(
457.2
mm) 
unless 
the boiler
’s listing or department approval or manufac-
turer’s instructions state 
otherwise.
1004.3.1 Top clearance.
Clearances from the tops of boilers to the ceiling or other overhead obstruction shall be 
in accordance with Table 1004.3.1.
TABLE 1004.3.1
BOILER TOP
CLEARANCES
BOILER TYPE
MINIMUM 
CLEARANCES FROM 
TOP OF BOILER TO 
CEILING OR OTHER 
OVERHEAD 
OBSTRUCTION (feet)
All boilers with manholes on top of the 
boiler except where a greater clearance is 
required in this table.
3
All boilers without 
manholes on top of 
the boiler except high
-
pressure steam 
boilers and where a greater clearance is 
required in this table.
2
High
-
pressure steam boilers with steam 
generating capacity not exceeding 5,000 
pounds per hour.
3
High
-
pressure steam 
boilers with steam 
generating capacity exceeding 5,000 
pounds per hour.
7
High
-
pressure steam boilers having heat-
ing surface not exceeding 1,000 square 
feet.
3
High
-
pressure steam boilers having heat-
ing surface in excess of 1,000 square 
feet.
7
High
-
pressure steam boilers with input 
not exceeding 5,000,000 Btu/h.
3
BOILERS, WATER HEATERS AND PRESSURE VESSELS
High
-
pressure steam boilers with input in 
excess of 5,000,000 Btu/h.
7
Steam
-
heating boilers and hot water
-
heating boilers with input exceeding 
5,000,000 Btu/h.
3
Steam
-
heating boilers exceeding 5,000 
pounds of steam per hour.
3
Steam
-
heating boilers and hot water
-
heating boilers having heating surface 
exceeding 1,000 square feet.
3
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m
2
, 1 pound per hour = 0.4536
kg/h, 1 Btu/hr = 0.293 W.
1004.4 Mounting.
Equipment
and appliances
shall be set or mounted on a level base capable of supporting and dis-
tributing the weight contained thereon. Boilers, tanks and equipment shall be 
securely anchored to the structure. 
Equ
ipment and appliances requiring vibration isolation shall be installed as designed by a registered design profes-
sional
in accordance with the manufacturer’s instructions.
1004.5 Floors.
Boilers shall be mounted on floors of noncombustible 
construction, unless listed for mounting on 
combustible flooring. Vibration isolation shall be in accordance with Section 313. In buildings with residential occu-
pancies, boilers shall be installed in accordance with the requirements of Section 313.
1004.6 
Boiler rooms and enclosures.
Boiler rooms and enclosures and access thereto shall comply with Chapters 5 
and 10 of the 
New York City 
Building Code
and Chapter 3 of this code. Boiler rooms shall be equipped with a floor 
drain or other approved means for 
disposing
of liquid waste
in accordance with the 
New York City Plumbing Code
.
1004.7 Operating adjustments and instructions.
Hot water and steam boil
ers shall have all operating and safety 
controls set and operationally tested by the installing contractor. A 
complete
control diagram and boiler operating 
instructions shall be furnished by the installer for each installation.
A complete control diagram o
f a permanent type 
shall be located in the boiler room and shall be readily accessible.
1004.8 Burner controls.
Gas and oil modulating burners shall be provided with burner controls (oil and gas equiv-
alent ratings) in accordance with ASME CSD
-
1 and NFPA 85
.
1004.9 Conversion burners. 
Conversion burners shall be installed in accordance with ANSI Z21.8.
SECTION MC 1005
BOILER CONNECTIONS
1005.1 Valves.
Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple 
boil
er or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in 
the 
supply
and return piping.
Exception: 
Shutoff valves are not required in a system 
having
a single low
-
pressure steam boiler
of 350,000 Btu
/h 
(103 kW) output or less
.
1005.2 Potable water supply.
The water supply to all boilers, including but not limited to backflow prevention, shall 
be connected in accordance with the 
New
York City 
Plumbing Code
. 
SECTION MC 1006
SAFETY AND PRESSURE 
RELIEF VALVES
AND CONTROLS
1006.1 Safety valves for steam boilers. 
Steam boilers shall be protected with a safety valve 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
BOILERS, WATER HEATERS AND PRESSURE VESSELS
4.2.
UL 2106.
Exception:
Unlisted equipment shall obtain approval from the department.
5.
Controls and safety devices shall be tested and inspected in accordance with ASME CSD
-
1 and, as applicable, 
the 
ASME Boiler and Pressure Vessel Code
,
12 NYCRR Parts 4 and 14, and NFPA 85. Testing and inspection 
shall be performed by the burner manufacturer’s authorized representative in the presence of the licensed 
installer. 
6.
Inspection of the installed boiler assembly shall be performed by the dep
artment.
1004.2 Installation.
In addition to the requirements of this code, the installation of boilers shall conform to the 
man-
ufacturer’s
instructions. Operating instructions of a permanent type shall be 
located in
the boiler
room and readily 
accessible
.
Boilers shall have all controls set, adjusted and tested by the installer. The manufacturer’s rating data and 
the nameplate shall be attached to the boiler.
1004.3 Working clearance.
Clearances shall be maintained around boilers, generators, heaters, tanks and related 
equipment and appliances so as to permit inspection, servicing, repair, replacement and visibility of all gauges. When 
boilers are installed or replaced, clearance shall 
be provided to allow access for maintenance and repair
per the boiler’s 
listing and manufacturer’s instructions.
Passageways 
for inspection 
around all sides of boilers shall have an unob-
structed width of not less than 18 inches 
(
457.2
mm) 
unless 
the boiler
’s listing or department approval or manufac-
turer’s instructions state 
otherwise.
1004.3.1 Top clearance.
Clearances from the tops of boilers to the ceiling or other overhead obstruction shall be 
in accordance with Table 1004.3.1.
TABLE 1004.3.1
BOILER TOP
CLEARANCES
BOILER TYPE
MINIMUM 
CLEARANCES FROM 
TOP OF BOILER TO 
CEILING OR OTHER 
OVERHEAD 
OBSTRUCTION (feet)
All boilers with manholes on top of the 
boiler except where a greater clearance is 
required in this table.
3
All boilers without 
manholes on top of 
the boiler except high
-
pressure steam 
boilers and where a greater clearance is 
required in this table.
2
High
-
pressure steam boilers with steam 
generating capacity not exceeding 5,000 
pounds per hour.
3
High
-
pressure steam 
boilers with steam 
generating capacity exceeding 5,000 
pounds per hour.
7
High
-
pressure steam boilers having heat-
ing surface not exceeding 1,000 square 
feet.
3
High
-
pressure steam boilers having heat-
ing surface in excess of 1,000 square 
feet.
7
High
-
pressure steam boilers with input 
not exceeding 5,000,000 Btu/h.
3
BOILERS, WATER HEATERS AND PRESSURE VESSELS
High
-
pressure steam boilers with input in 
excess of 5,000,000 Btu/h.
7
Steam
-
heating boilers and hot water
-
heating boilers with input exceeding 
5,000,000 Btu/h.
3
Steam
-
heating boilers exceeding 5,000 
pounds of steam per hour.
3
Steam
-
heating boilers and hot water
-
heating boilers having heating surface 
exceeding 1,000 square feet.
3
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m
2
, 1 pound per hour = 0.4536
kg/h, 1 Btu/hr = 0.293 W.
1004.4 Mounting.
Equipment
and appliances
shall be set or mounted on a level base capable of supporting and dis-
tributing the weight contained thereon. Boilers, tanks and equipment shall be 
securely anchored to the structure. 
Equ
ipment and appliances requiring vibration isolation shall be installed as designed by a registered design profes-
sional
in accordance with the manufacturer’s instructions.
1004.5 Floors.
Boilers shall be mounted on floors of noncombustible 
construction, unless listed for mounting on 
combustible flooring. Vibration isolation shall be in accordance with Section 313. In buildings with residential occu-
pancies, boilers shall be installed in accordance with the requirements of Section 313.
1004.6 
Boiler rooms and enclosures.
Boiler rooms and enclosures and access thereto shall comply with Chapters 5 
and 10 of the 
New York City 
Building Code
and Chapter 3 of this code. Boiler rooms shall be equipped with a floor 
drain or other approved means for 
disposing
of liquid waste
in accordance with the 
New York City Plumbing Code
.
1004.7 Operating adjustments and instructions.
Hot water and steam boil
ers shall have all operating and safety 
controls set and operationally tested by the installing contractor. A 
complete
control diagram and boiler operating 
instructions shall be furnished by the installer for each installation.
A complete control diagram o
f a permanent type 
shall be located in the boiler room and shall be readily accessible.
1004.8 Burner controls.
Gas and oil modulating burners shall be provided with burner controls (oil and gas equiv-
alent ratings) in accordance with ASME CSD
-
1 and NFPA 85
.
1004.9 Conversion burners. 
Conversion burners shall be installed in accordance with ANSI Z21.8.
SECTION MC 1005
BOILER CONNECTIONS
1005.1 Valves.
Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple 
boil
er or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in 
the 
supply
and return piping.
Exception: 
Shutoff valves are not required in a system 
having
a single low
-
pressure steam boiler
of 350,000 Btu
/h 
(103 kW) output or less
.
1005.2 Potable water supply.
The water supply to all boilers, including but not limited to backflow prevention, shall 
be connected in accordance with the 
New
York City 
Plumbing Code
. 
SECTION MC 1006
SAFETY AND PRESSURE 
RELIEF VALVES
AND CONTROLS
1006.1 Safety valves for steam boilers. 
Steam boilers shall be protected with a safety valve 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1006.2 Safety relief valves for hot water boilers.
Hot water 
boilers shall be protected with a safety relief valve 
in 
accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1
.
1006.3 Pressure relief for pressure vessels. 
Pressure vessels
shall be protected with a pressure relief valve or 
pres-
sure
-
limit
ing device as required by the manufacturer’s instructions for the pressure vessel and 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
1006.4 Standards of safety and safety relief valves.
Safety and safety relief valves shall be l
isted and labeled, and 
shall have a minimum rated capacity for the equipment or appliances served. Safety and safety relief valves shall be 
set at not greater than the nameplate pressure rating of the boiler or pressure vessel and shall be in accordance wi
th 
the
ASME Boiler and Pressure Vessel Code
or the ASME CSD
-
1
.
1006.5 Installation.
Safety or relief valves shall be installed directly into the safety or relief valve opening on the 
boiler or pressure vessel. Valves shall not be located on either side of a safety or relief valve connection. The relief 
valve drain shall 
discharge by gravi
ty to a nonhazardous point of discharge without obstruction.‡
1006.6 Safety and relief valve discharge.
Safety and relief valve discharge pipes shall be of rigid pipe that is approved 
for the temperature of the system. The discharge pipe shall
, at a minimu
m,
be the same diameter as the safety or relief 
valve outlet. Safety and relief valve discharge pipes shall be properly supported to prevent stress on the valve and 
vessel. Safety and relief valves shall not discharge so as to be a hazard, a potential caus
e of damage or otherwise a 
nuisance. 
Discharge of hazardous materials must be properly contained in a method approved by the department. 
High
-
pressure
-
steam safety valves shall be vented to the outside of the structure. Where a low
-
pressure safety valve 
or
a relief valve discharges to the drainage system, the installation shall conform to the 
New York City 
Plumbing Code
.
1006.7 Boiler safety devices.
Boilers shall be equipped with controls and limit devices as required by the manufac-
turer’s instructions and
the conditions of the listing.
1006.8 Electrical requirements.
The power supply to the electrical control system shall be from a two
-
wire branch 
circuit
that has a grounded conductor, or from an isolation 
trans
-
former
with a two
-
wire secondary. Where an i
solation 
transformer is provided, one conductor of the secondary 
winding
shall be grounded. Control voltage shall not exceed 
150 volts nominal, line to line. Control and limit devices shall 
interrupt
the ungrounded side of the circuit. A means 
of manually 
disconnecting the control circuit shall be provided and controls shall be arranged so that when deener-
gized, the burner shall be inoperative. Such disconnecting means shall be capable of being locked in the off position 
and shall be provided with ready acc
ess.
1006.8.1 Remote control (shutdown).
A remote control shall be provided to stop the flow of oil and/or gas and 
combustion air to any burner or fuel
-
burning internal combustion equipment. Such a control shall be provided 
along every means of egress from
the room in which the burner or equipment is located. Each remote control shall 
be located outside of, but as close as practicable to the burner or equipment room itself and shall be labeled: 
“REMOTE CONTROL FOR BURNER.”
Exception:
Where an outside locati
on is impracticable, the remote control shutdown may be provided immedi-
ately inside the room in which the burner or equipment is located.
Such location must be accessible at all times.
1006.9 Carbon monoxide detectors.
Carbon monoxide detectors shall be p
rovided in all fuel
-
fired appliance rooms 
to detect the level of carbon monoxide in the room and signal an alarm.    Such detectors shall be listed and installed 
in accordance with Chapter 9 of the 
New York City Building Code
.
SECTION 
MC 
1007
BOILER 
LOW
-
WATER CUTOFF
1007.1 General.
Steam and hot water boilers shall be protected with 
dual
low
-
water cutoff control, with each control 
independently piped to the pressure vessel in accordance with ASME CSD
-
1. For hydronic boilers, the low
-
water cut 
out may 
be located in the supply piping above the boiler before any intervening valve. A flow
-
sensing control installed 
in accordance with ASME CSD
-
1 shall be considered a low
-
water cutoff for the purposes of this section. 
Exception: 
Hot water
boilers 
located wit
hin a dwelling unit supplying only 
that 
unit and having a total heat input
of 
less than 400,000 Btu/h (117.2 kW) may be
protected 
by only one low
-
water cutoff 
control.
‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
BOILERS, WATER HEATERS AND PRESSURE VESSELS
4.2.
UL 2106.
Exception:
Unlisted equipment shall obtain approval from the department.
5.
Controls and safety devices shall be tested and inspected in accordance with ASME CSD
-
1 and, as applicable, 
the 
ASME Boiler and Pressure Vessel Code
,
12 NYCRR Parts 4 and 14, and NFPA 85. Testing and inspection 
shall be performed by the burner manufacturer’s authorized representative in the presence of the licensed 
installer. 
6.
Inspection of the installed boiler assembly shall be performed by the dep
artment.
1004.2 Installation.
In addition to the requirements of this code, the installation of boilers shall conform to the 
man-
ufacturer’s
instructions. Operating instructions of a permanent type shall be 
located in
the boiler
room and readily 
accessible
.
Boilers shall have all controls set, adjusted and tested by the installer. The manufacturer’s rating data and 
the nameplate shall be attached to the boiler.
1004.3 Working clearance.
Clearances shall be maintained around boilers, generators, heaters, tanks and related 
equipment and appliances so as to permit inspection, servicing, repair, replacement and visibility of all gauges. When 
boilers are installed or replaced, clearance shall 
be provided to allow access for maintenance and repair
per the boiler’s 
listing and manufacturer’s instructions.
Passageways 
for inspection 
around all sides of boilers shall have an unob-
structed width of not less than 18 inches 
(
457.2
mm) 
unless 
the boiler
’s listing or department approval or manufac-
turer’s instructions state 
otherwise.
1004.3.1 Top clearance.
Clearances from the tops of boilers to the ceiling or other overhead obstruction shall be 
in accordance with Table 1004.3.1.
TABLE 1004.3.1
BOILER TOP
CLEARANCES
BOILER TYPE
MINIMUM 
CLEARANCES FROM 
TOP OF BOILER TO 
CEILING OR OTHER 
OVERHEAD 
OBSTRUCTION (feet)
All boilers with manholes on top of the 
boiler except where a greater clearance is 
required in this table.
3
All boilers without 
manholes on top of 
the boiler except high
-
pressure steam 
boilers and where a greater clearance is 
required in this table.
2
High
-
pressure steam boilers with steam 
generating capacity not exceeding 5,000 
pounds per hour.
3
High
-
pressure steam 
boilers with steam 
generating capacity exceeding 5,000 
pounds per hour.
7
High
-
pressure steam boilers having heat-
ing surface not exceeding 1,000 square 
feet.
3
High
-
pressure steam boilers having heat-
ing surface in excess of 1,000 square 
feet.
7
High
-
pressure steam boilers with input 
not exceeding 5,000,000 Btu/h.
3
BOILERS, WATER HEATERS AND PRESSURE VESSELS
High
-
pressure steam boilers with input in 
excess of 5,000,000 Btu/h.
7
Steam
-
heating boilers and hot water
-
heating boilers with input exceeding 
5,000,000 Btu/h.
3
Steam
-
heating boilers exceeding 5,000 
pounds of steam per hour.
3
Steam
-
heating boilers and hot water
-
heating boilers having heating surface 
exceeding 1,000 square feet.
3
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m
2
, 1 pound per hour = 0.4536
kg/h, 1 Btu/hr = 0.293 W.
1004.4 Mounting.
Equipment
and appliances
shall be set or mounted on a level base capable of supporting and dis-
tributing the weight contained thereon. Boilers, tanks and equipment shall be 
securely anchored to the structure. 
Equ
ipment and appliances requiring vibration isolation shall be installed as designed by a registered design profes-
sional
in accordance with the manufacturer’s instructions.
1004.5 Floors.
Boilers shall be mounted on floors of noncombustible 
construction, unless listed for mounting on 
combustible flooring. Vibration isolation shall be in accordance with Section 313. In buildings with residential occu-
pancies, boilers shall be installed in accordance with the requirements of Section 313.
1004.6 
Boiler rooms and enclosures.
Boiler rooms and enclosures and access thereto shall comply with Chapters 5 
and 10 of the 
New York City 
Building Code
and Chapter 3 of this code. Boiler rooms shall be equipped with a floor 
drain or other approved means for 
disposing
of liquid waste
in accordance with the 
New York City Plumbing Code
.
1004.7 Operating adjustments and instructions.
Hot water and steam boil
ers shall have all operating and safety 
controls set and operationally tested by the installing contractor. A 
complete
control diagram and boiler operating 
instructions shall be furnished by the installer for each installation.
A complete control diagram o
f a permanent type 
shall be located in the boiler room and shall be readily accessible.
1004.8 Burner controls.
Gas and oil modulating burners shall be provided with burner controls (oil and gas equiv-
alent ratings) in accordance with ASME CSD
-
1 and NFPA 85
.
1004.9 Conversion burners. 
Conversion burners shall be installed in accordance with ANSI Z21.8.
SECTION MC 1005
BOILER CONNECTIONS
1005.1 Valves.
Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple 
boil
er or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in 
the 
supply
and return piping.
Exception: 
Shutoff valves are not required in a system 
having
a single low
-
pressure steam boiler
of 350,000 Btu
/h 
(103 kW) output or less
.
1005.2 Potable water supply.
The water supply to all boilers, including but not limited to backflow prevention, shall 
be connected in accordance with the 
New
York City 
Plumbing Code
. 
SECTION MC 1006
SAFETY AND PRESSURE 
RELIEF VALVES
AND CONTROLS
1006.1 Safety valves for steam boilers. 
Steam boilers shall be protected with a safety valve 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1006.2 Safety relief valves for hot water boilers.
Hot water 
boilers shall be protected with a safety relief valve 
in 
accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1
.
1006.3 Pressure relief for pressure vessels. 
Pressure vessels
shall be protected with a pressure relief valve or 
pres-
sure
-
limit
ing device as required by the manufacturer’s instructions for the pressure vessel and 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
1006.4 Standards of safety and safety relief valves.
Safety and safety relief valves shall be l
isted and labeled, and 
shall have a minimum rated capacity for the equipment or appliances served. Safety and safety relief valves shall be 
set at not greater than the nameplate pressure rating of the boiler or pressure vessel and shall be in accordance wi
th 
the
ASME Boiler and Pressure Vessel Code
or the ASME CSD
-
1
.
1006.5 Installation.
Safety or relief valves shall be installed directly into the safety or relief valve opening on the 
boiler or pressure vessel. Valves shall not be located on either side of a safety or relief valve connection. The relief 
valve drain shall 
discharge by gravi
ty to a nonhazardous point of discharge without obstruction.‡
1006.6 Safety and relief valve discharge.
Safety and relief valve discharge pipes shall be of rigid pipe that is approved 
for the temperature of the system. The discharge pipe shall
, at a minimu
m,
be the same diameter as the safety or relief 
valve outlet. Safety and relief valve discharge pipes shall be properly supported to prevent stress on the valve and 
vessel. Safety and relief valves shall not discharge so as to be a hazard, a potential caus
e of damage or otherwise a 
nuisance. 
Discharge of hazardous materials must be properly contained in a method approved by the department. 
High
-
pressure
-
steam safety valves shall be vented to the outside of the structure. Where a low
-
pressure safety valve 
or
a relief valve discharges to the drainage system, the installation shall conform to the 
New York City 
Plumbing Code
.
1006.7 Boiler safety devices.
Boilers shall be equipped with controls and limit devices as required by the manufac-
turer’s instructions and
the conditions of the listing.
1006.8 Electrical requirements.
The power supply to the electrical control system shall be from a two
-
wire branch 
circuit
that has a grounded conductor, or from an isolation 
trans
-
former
with a two
-
wire secondary. Where an i
solation 
transformer is provided, one conductor of the secondary 
winding
shall be grounded. Control voltage shall not exceed 
150 volts nominal, line to line. Control and limit devices shall 
interrupt
the ungrounded side of the circuit. A means 
of manually 
disconnecting the control circuit shall be provided and controls shall be arranged so that when deener-
gized, the burner shall be inoperative. Such disconnecting means shall be capable of being locked in the off position 
and shall be provided with ready acc
ess.
1006.8.1 Remote control (shutdown).
A remote control shall be provided to stop the flow of oil and/or gas and 
combustion air to any burner or fuel
-
burning internal combustion equipment. Such a control shall be provided 
along every means of egress from
the room in which the burner or equipment is located. Each remote control shall 
be located outside of, but as close as practicable to the burner or equipment room itself and shall be labeled: 
“REMOTE CONTROL FOR BURNER.”
Exception:
Where an outside locati
on is impracticable, the remote control shutdown may be provided immedi-
ately inside the room in which the burner or equipment is located.
Such location must be accessible at all times.
1006.9 Carbon monoxide detectors.
Carbon monoxide detectors shall be p
rovided in all fuel
-
fired appliance rooms 
to detect the level of carbon monoxide in the room and signal an alarm.    Such detectors shall be listed and installed 
in accordance with Chapter 9 of the 
New York City Building Code
.
SECTION 
MC 
1007
BOILER 
LOW
-
WATER CUTOFF
1007.1 General.
Steam and hot water boilers shall be protected with 
dual
low
-
water cutoff control, with each control 
independently piped to the pressure vessel in accordance with ASME CSD
-
1. For hydronic boilers, the low
-
water cut 
out may 
be located in the supply piping above the boiler before any intervening valve. A flow
-
sensing control installed 
in accordance with ASME CSD
-
1 shall be considered a low
-
water cutoff for the purposes of this section. 
Exception: 
Hot water
boilers 
located wit
hin a dwelling unit supplying only 
that 
unit and having a total heat input
of 
less than 400,000 Btu/h (117.2 kW) may be
protected 
by only one low
-
water cutoff 
control.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1007.2 Operation. 
Low
-
water cutoff controls and flow
-
sensing controls required by Section 1007.1 shall automati-
cally stop the combustion operation of the appliance when the water level drops below the lowest safe water level as 
established by the manufacturer 
and in accordance with ASME CSD
-
1, 
or when water circulation stops, respectively.
10
07.3 Low
-
water cut out maintenance and testing.
Low
-
water cut outs shall be maintained in accordance with 
ASME CSD
-
1 and the manufacturer’s specifications. An operator shall test low
-
water cut outs as follows: (1) high 
pressure steam boilers every shift, (
2) low pressure steam boilers daily and (3) hot water boilers monthly. Slow drain 
tests shall be conducted for steam boilers every six months.
Every year, low
-
water cut outs and associated piping for 
steam boilers shall be opened, cleaned and inspected. 
Re
cords of all testing, cleaning, and inspection required by this 
section shall be maintained, and made available to the department upon request. 
SECTION MC 1008
BOILER BLOWOFF/BLOWDOWN VALVES
1008.1 General.
Every boiler
shall be equipped with blowoff
/blow
down
valve(s). The valve(s) shall be installed in 
the 
openings
provided on the boiler. The minimum 
quantity and 
size of the valve(s) and associated piping shall be the 
quantity and 
size specified by the boiler manufacturer or the 
quantity and size of the boiler blowoff
/blowdown 
valve 
opening. Where the maximum allowable working pressure of the boiler exceeds 15 psig (103.4 kPa), two bottom 
blowoff valves shall be provided consisting 
of either two slow
-
opening valves in series or one quick
-
opening valve 
and one slow
-
opening valve in series, with the quick
-
opening valve installed closest to the boiler.
1008.2 Discharge.
Blowoff
/blowdown
valves shall discharge to a safe place of disposal. Where discharging to the 
drainage system, the installation shall conform to the 
New York City 
Plumbing Code.
1008.3 Maintenance.
Blowdown lines shall be inspected annually to verify they are free of deposits and in good 
working condition.
SECTION MC 1009
HOT WATER BOILER EXPANSION TANK
1009.1 Where required.
An expansion tank shall be installed in every hot water system. For multiple boiler installa-
tions, not less than one expansion tank is required. Expansion tanks shall be of the closed or open type. Tanks shall 
be rated for the pressure of the hot water system.
Lockable shutoff valves shall be installed at connections to all 
expansion tanks. Valves shall remain locked in the open position.
1009.2 Closed
-
type expansion tanks.
Closed
-
type expansion tanks shall be installed in accordance with the manu-
facturer’s instructions. Expansion tanks for systems designed to have an operating pressure in excess of 30 psi (205.8 
kPa) shall be constructed and certified in accordance with the 
ASME Boiler and Pressure Vessel Code
. The size of the 
tank shall be based on the capacity of the hot
-
water
-
heating system. The minimum size of the tank shall be determined 
in accordance with the following equation where all necessary
information is known:
V
t
  =  
(
0
.
00041T
−0
.
0466
)
V
s
�
P
a
P
f
�
−�
P
a
P
o
�
(Equation 10
-
1)
For SI:
V
t
  =  
(
0.
000738T
−
0.
03348
)
V
s
�
P
a
P
f
�−�
P
a
P
o
�
where:
V
t
= 
Minimum volume of tanks (gallons) (L).
V
s
= 
Volume of system, not including expansion tanks
(gallons) (L).
T 
= 
Average operating temperature (
°
F) (
°
C).
P
a
= 
Atmospheric pressure (psi) (kPa).
BOILERS, WATER HEATERS AND PRESSURE VESSELS
P
f
= 
Fill pressure (psi) (kPa).
P
o
= 
Maximum operating pressure (psi) (kPa).
Where all necessary information is not known, the minimum size of the tank shall be 
determined from Table 1009.2.
TABLE 1009.2
CLOSED
-
TYPE EXPANSION TANK SIZING
SYSTEM VOLUME
IN GALLONS
TANK CAPACITIES IN GALLONS
Pressurized
Diaphragm Type
Nonpressurized
Type
100
9
15
200
17
30
300
25
45
400
33
60
500
42
75
1,000
83
150
2,000
165
300
For SI: 1 gallon = 3.795 L.
1009.3 Open
-
type expansion tanks.
Open
-
type expansion tanks shall be located not less than 4 feet (1219.2 mm) 
above the highest heating element. The tank shall be adequately sized for the hot water system. An overflow with a 
minimum 
diameter
of 1 inch (25.4 mm) shall be installed at the to
p of the tank. The overflow shall discharge to the 
drainage system in 
accordance
with the 
New York City 
Plumbing Code.
SECTION MC 1010
GAUGES
1010.1 Hot water boiler gauges.
Every hot water boiler shall have a pressure gauge and a temperature gauge, or a 
c
ombination pressure and temperature gauge. The gauges shall indicate the temperature and pressure within the normal 
range of the system’s operation.
1010.2 Steam boiler gauges.
Every steam boiler shall have a water
-
gauge glass and a pressure gauge with a s
iphon. 
The pressure gauge shall indicate the pressure within the normal range of the system’s operation.
1010.2.1 Water
-
gauge glass.
The gauge glass shall be installed in accordance with the 
ASME Boiler and Pressure 
Vessel Code 
or ASME CSD
-
1.
SECTION MC 1011
TESTS
1011.1 Tests.
Upon completion of the assembly and 
installation
of boilers and pressure vessels, acceptance tests shall 
be conducted in accordance with the requirements of the 
ASME Boiler and Pressure Vessel Code
. Boilers shall not 
be placed in operation upon completion of construction until they have been inspected
a
nd 
tested and a certificate of 
compliance has been issued by the commissioner. All final inspections and
tests 
for boilers shall be witnessed by a 
qualified boiler inspector in the employ of the department or a duly authorized insurance company as provided
in 
Section 204 of the Labor Law of the State of New York. Equipment having an input of not more than 350,000 Btu/h 
(103 kW) shall be exempt from this requirement. Where field assembly of pressure vessels or boilers is required, a
copy of 
the completed H
-
2
, P
-
2 or U
-
1 Manufacturer’s Data Report and the completed Appendix C of ASME CSD
-
1 
required by the 
ASME Boiler and Pressure Vessel Code
shall be submitted to the 
department
.
1011.1.1 Fitness for service. 
When a boiler or pressure vessel has exceeded its us
eful life or has been subjected to 
an event that may have impacted the integrity of the pressure vessel, the department may require that a fitness for 
service study be completed. The study shall be completed in accordance with the 
National Board Inspection
Code
Part 2, Section 4, and documented in accordance with the National Board 403 form.
‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
BOILERS, WATER HEATERS AND PRESSURE VESSELS
4.2.
UL 2106.
Exception:
Unlisted equipment shall obtain approval from the department.
5.
Controls and safety devices shall be tested and inspected in accordance with ASME CSD
-
1 and, as applicable, 
the 
ASME Boiler and Pressure Vessel Code
,
12 NYCRR Parts 4 and 14, and NFPA 85. Testing and inspection 
shall be performed by the burner manufacturer’s authorized representative in the presence of the licensed 
installer. 
6.
Inspection of the installed boiler assembly shall be performed by the dep
artment.
1004.2 Installation.
In addition to the requirements of this code, the installation of boilers shall conform to the 
man-
ufacturer’s
instructions. Operating instructions of a permanent type shall be 
located in
the boiler
room and readily 
accessible
.
Boilers shall have all controls set, adjusted and tested by the installer. The manufacturer’s rating data and 
the nameplate shall be attached to the boiler.
1004.3 Working clearance.
Clearances shall be maintained around boilers, generators, heaters, tanks and related 
equipment and appliances so as to permit inspection, servicing, repair, replacement and visibility of all gauges. When 
boilers are installed or replaced, clearance shall 
be provided to allow access for maintenance and repair
per the boiler’s 
listing and manufacturer’s instructions.
Passageways 
for inspection 
around all sides of boilers shall have an unob-
structed width of not less than 18 inches 
(
457.2
mm) 
unless 
the boiler
’s listing or department approval or manufac-
turer’s instructions state 
otherwise.
1004.3.1 Top clearance.
Clearances from the tops of boilers to the ceiling or other overhead obstruction shall be 
in accordance with Table 1004.3.1.
TABLE 1004.3.1
BOILER TOP
CLEARANCES
BOILER TYPE
MINIMUM 
CLEARANCES FROM 
TOP OF BOILER TO 
CEILING OR OTHER 
OVERHEAD 
OBSTRUCTION (feet)
All boilers with manholes on top of the 
boiler except where a greater clearance is 
required in this table.
3
All boilers without 
manholes on top of 
the boiler except high
-
pressure steam 
boilers and where a greater clearance is 
required in this table.
2
High
-
pressure steam boilers with steam 
generating capacity not exceeding 5,000 
pounds per hour.
3
High
-
pressure steam 
boilers with steam 
generating capacity exceeding 5,000 
pounds per hour.
7
High
-
pressure steam boilers having heat-
ing surface not exceeding 1,000 square 
feet.
3
High
-
pressure steam boilers having heat-
ing surface in excess of 1,000 square 
feet.
7
High
-
pressure steam boilers with input 
not exceeding 5,000,000 Btu/h.
3
BOILERS, WATER HEATERS AND PRESSURE VESSELS
High
-
pressure steam boilers with input in 
excess of 5,000,000 Btu/h.
7
Steam
-
heating boilers and hot water
-
heating boilers with input exceeding 
5,000,000 Btu/h.
3
Steam
-
heating boilers exceeding 5,000 
pounds of steam per hour.
3
Steam
-
heating boilers and hot water
-
heating boilers having heating surface 
exceeding 1,000 square feet.
3
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m
2
, 1 pound per hour = 0.4536
kg/h, 1 Btu/hr = 0.293 W.
1004.4 Mounting.
Equipment
and appliances
shall be set or mounted on a level base capable of supporting and dis-
tributing the weight contained thereon. Boilers, tanks and equipment shall be 
securely anchored to the structure. 
Equ
ipment and appliances requiring vibration isolation shall be installed as designed by a registered design profes-
sional
in accordance with the manufacturer’s instructions.
1004.5 Floors.
Boilers shall be mounted on floors of noncombustible 
construction, unless listed for mounting on 
combustible flooring. Vibration isolation shall be in accordance with Section 313. In buildings with residential occu-
pancies, boilers shall be installed in accordance with the requirements of Section 313.
1004.6 
Boiler rooms and enclosures.
Boiler rooms and enclosures and access thereto shall comply with Chapters 5 
and 10 of the 
New York City 
Building Code
and Chapter 3 of this code. Boiler rooms shall be equipped with a floor 
drain or other approved means for 
disposing
of liquid waste
in accordance with the 
New York City Plumbing Code
.
1004.7 Operating adjustments and instructions.
Hot water and steam boil
ers shall have all operating and safety 
controls set and operationally tested by the installing contractor. A 
complete
control diagram and boiler operating 
instructions shall be furnished by the installer for each installation.
A complete control diagram o
f a permanent type 
shall be located in the boiler room and shall be readily accessible.
1004.8 Burner controls.
Gas and oil modulating burners shall be provided with burner controls (oil and gas equiv-
alent ratings) in accordance with ASME CSD
-
1 and NFPA 85
.
1004.9 Conversion burners. 
Conversion burners shall be installed in accordance with ANSI Z21.8.
SECTION MC 1005
BOILER CONNECTIONS
1005.1 Valves.
Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple 
boil
er or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in 
the 
supply
and return piping.
Exception: 
Shutoff valves are not required in a system 
having
a single low
-
pressure steam boiler
of 350,000 Btu
/h 
(103 kW) output or less
.
1005.2 Potable water supply.
The water supply to all boilers, including but not limited to backflow prevention, shall 
be connected in accordance with the 
New
York City 
Plumbing Code
. 
SECTION MC 1006
SAFETY AND PRESSURE 
RELIEF VALVES
AND CONTROLS
1006.1 Safety valves for steam boilers. 
Steam boilers shall be protected with a safety valve 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1006.2 Safety relief valves for hot water boilers.
Hot water 
boilers shall be protected with a safety relief valve 
in 
accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1
.
1006.3 Pressure relief for pressure vessels. 
Pressure vessels
shall be protected with a pressure relief valve or 
pres-
sure
-
limit
ing device as required by the manufacturer’s instructions for the pressure vessel and 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
1006.4 Standards of safety and safety relief valves.
Safety and safety relief valves shall be l
isted and labeled, and 
shall have a minimum rated capacity for the equipment or appliances served. Safety and safety relief valves shall be 
set at not greater than the nameplate pressure rating of the boiler or pressure vessel and shall be in accordance wi
th 
the
ASME Boiler and Pressure Vessel Code
or the ASME CSD
-
1
.
1006.5 Installation.
Safety or relief valves shall be installed directly into the safety or relief valve opening on the 
boiler or pressure vessel. Valves shall not be located on either side of a safety or relief valve connection. The relief 
valve drain shall 
discharge by gravi
ty to a nonhazardous point of discharge without obstruction.‡
1006.6 Safety and relief valve discharge.
Safety and relief valve discharge pipes shall be of rigid pipe that is approved 
for the temperature of the system. The discharge pipe shall
, at a minimu
m,
be the same diameter as the safety or relief 
valve outlet. Safety and relief valve discharge pipes shall be properly supported to prevent stress on the valve and 
vessel. Safety and relief valves shall not discharge so as to be a hazard, a potential caus
e of damage or otherwise a 
nuisance. 
Discharge of hazardous materials must be properly contained in a method approved by the department. 
High
-
pressure
-
steam safety valves shall be vented to the outside of the structure. Where a low
-
pressure safety valve 
or
a relief valve discharges to the drainage system, the installation shall conform to the 
New York City 
Plumbing Code
.
1006.7 Boiler safety devices.
Boilers shall be equipped with controls and limit devices as required by the manufac-
turer’s instructions and
the conditions of the listing.
1006.8 Electrical requirements.
The power supply to the electrical control system shall be from a two
-
wire branch 
circuit
that has a grounded conductor, or from an isolation 
trans
-
former
with a two
-
wire secondary. Where an i
solation 
transformer is provided, one conductor of the secondary 
winding
shall be grounded. Control voltage shall not exceed 
150 volts nominal, line to line. Control and limit devices shall 
interrupt
the ungrounded side of the circuit. A means 
of manually 
disconnecting the control circuit shall be provided and controls shall be arranged so that when deener-
gized, the burner shall be inoperative. Such disconnecting means shall be capable of being locked in the off position 
and shall be provided with ready acc
ess.
1006.8.1 Remote control (shutdown).
A remote control shall be provided to stop the flow of oil and/or gas and 
combustion air to any burner or fuel
-
burning internal combustion equipment. Such a control shall be provided 
along every means of egress from
the room in which the burner or equipment is located. Each remote control shall 
be located outside of, but as close as practicable to the burner or equipment room itself and shall be labeled: 
“REMOTE CONTROL FOR BURNER.”
Exception:
Where an outside locati
on is impracticable, the remote control shutdown may be provided immedi-
ately inside the room in which the burner or equipment is located.
Such location must be accessible at all times.
1006.9 Carbon monoxide detectors.
Carbon monoxide detectors shall be p
rovided in all fuel
-
fired appliance rooms 
to detect the level of carbon monoxide in the room and signal an alarm.    Such detectors shall be listed and installed 
in accordance with Chapter 9 of the 
New York City Building Code
.
SECTION 
MC 
1007
BOILER 
LOW
-
WATER CUTOFF
1007.1 General.
Steam and hot water boilers shall be protected with 
dual
low
-
water cutoff control, with each control 
independently piped to the pressure vessel in accordance with ASME CSD
-
1. For hydronic boilers, the low
-
water cut 
out may 
be located in the supply piping above the boiler before any intervening valve. A flow
-
sensing control installed 
in accordance with ASME CSD
-
1 shall be considered a low
-
water cutoff for the purposes of this section. 
Exception: 
Hot water
boilers 
located wit
hin a dwelling unit supplying only 
that 
unit and having a total heat input
of 
less than 400,000 Btu/h (117.2 kW) may be
protected 
by only one low
-
water cutoff 
control.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1007.2 Operation. 
Low
-
water cutoff controls and flow
-
sensing controls required by Section 1007.1 shall automati-
cally stop the combustion operation of the appliance when the water level drops below the lowest safe water level as 
established by the manufacturer 
and in accordance with ASME CSD
-
1, 
or when water circulation stops, respectively.
10
07.3 Low
-
water cut out maintenance and testing.
Low
-
water cut outs shall be maintained in accordance with 
ASME CSD
-
1 and the manufacturer’s specifications. An operator shall test low
-
water cut outs as follows: (1) high 
pressure steam boilers every shift, (
2) low pressure steam boilers daily and (3) hot water boilers monthly. Slow drain 
tests shall be conducted for steam boilers every six months.
Every year, low
-
water cut outs and associated piping for 
steam boilers shall be opened, cleaned and inspected. 
Re
cords of all testing, cleaning, and inspection required by this 
section shall be maintained, and made available to the department upon request. 
SECTION MC 1008
BOILER BLOWOFF/BLOWDOWN VALVES
1008.1 General.
Every boiler
shall be equipped with blowoff
/blow
down
valve(s). The valve(s) shall be installed in 
the 
openings
provided on the boiler. The minimum 
quantity and 
size of the valve(s) and associated piping shall be the 
quantity and 
size specified by the boiler manufacturer or the 
quantity and size of the boiler blowoff
/blowdown 
valve 
opening. Where the maximum allowable working pressure of the boiler exceeds 15 psig (103.4 kPa), two bottom 
blowoff valves shall be provided consisting 
of either two slow
-
opening valves in series or one quick
-
opening valve 
and one slow
-
opening valve in series, with the quick
-
opening valve installed closest to the boiler.
1008.2 Discharge.
Blowoff
/blowdown
valves shall discharge to a safe place of disposal. Where discharging to the 
drainage system, the installation shall conform to the 
New York City 
Plumbing Code.
1008.3 Maintenance.
Blowdown lines shall be inspected annually to verify they are free of deposits and in good 
working condition.
SECTION MC 1009
HOT WATER BOILER EXPANSION TANK
1009.1 Where required.
An expansion tank shall be installed in every hot water system. For multiple boiler installa-
tions, not less than one expansion tank is required. Expansion tanks shall be of the closed or open type. Tanks shall 
be rated for the pressure of the hot water system.
Lockable shutoff valves shall be installed at connections to all 
expansion tanks. Valves shall remain locked in the open position.
1009.2 Closed
-
type expansion tanks.
Closed
-
type expansion tanks shall be installed in accordance with the manu-
facturer’s instructions. Expansion tanks for systems designed to have an operating pressure in excess of 30 psi (205.8 
kPa) shall be constructed and certified in accordance with the 
ASME Boiler and Pressure Vessel Code
. The size of the 
tank shall be based on the capacity of the hot
-
water
-
heating system. The minimum size of the tank shall be determined 
in accordance with the following equation where all necessary
information is known:
V
t
  =  
(
0
.
00041T
−0
.
0466
)
V
s
�
P
a
P
f
�
−�
P
a
P
o
�
(Equation 10
-
1)
For SI:
V
t
  =  
(
0.
000738T
−
0.
03348
)
V
s
�
P
a
P
f
�−�
P
a
P
o
�
where:
V
t
= 
Minimum volume of tanks (gallons) (L).
V
s
= 
Volume of system, not including expansion tanks
(gallons) (L).
T 
= 
Average operating temperature (
°
F) (
°
C).
P
a
= 
Atmospheric pressure (psi) (kPa).
BOILERS, WATER HEATERS AND PRESSURE VESSELS
P
f
= 
Fill pressure (psi) (kPa).
P
o
= 
Maximum operating pressure (psi) (kPa).
Where all necessary information is not known, the minimum size of the tank shall be 
determined from Table 1009.2.
TABLE 1009.2
CLOSED
-
TYPE EXPANSION TANK SIZING
SYSTEM VOLUME
IN GALLONS
TANK CAPACITIES IN GALLONS
Pressurized
Diaphragm Type
Nonpressurized
Type
100
9
15
200
17
30
300
25
45
400
33
60
500
42
75
1,000
83
150
2,000
165
300
For SI: 1 gallon = 3.795 L.
1009.3 Open
-
type expansion tanks.
Open
-
type expansion tanks shall be located not less than 4 feet (1219.2 mm) 
above the highest heating element. The tank shall be adequately sized for the hot water system. An overflow with a 
minimum 
diameter
of 1 inch (25.4 mm) shall be installed at the to
p of the tank. The overflow shall discharge to the 
drainage system in 
accordance
with the 
New York City 
Plumbing Code.
SECTION MC 1010
GAUGES
1010.1 Hot water boiler gauges.
Every hot water boiler shall have a pressure gauge and a temperature gauge, or a 
c
ombination pressure and temperature gauge. The gauges shall indicate the temperature and pressure within the normal 
range of the system’s operation.
1010.2 Steam boiler gauges.
Every steam boiler shall have a water
-
gauge glass and a pressure gauge with a s
iphon. 
The pressure gauge shall indicate the pressure within the normal range of the system’s operation.
1010.2.1 Water
-
gauge glass.
The gauge glass shall be installed in accordance with the 
ASME Boiler and Pressure 
Vessel Code 
or ASME CSD
-
1.
SECTION MC 1011
TESTS
1011.1 Tests.
Upon completion of the assembly and 
installation
of boilers and pressure vessels, acceptance tests shall 
be conducted in accordance with the requirements of the 
ASME Boiler and Pressure Vessel Code
. Boilers shall not 
be placed in operation upon completion of construction until they have been inspected
a
nd 
tested and a certificate of 
compliance has been issued by the commissioner. All final inspections and
tests 
for boilers shall be witnessed by a 
qualified boiler inspector in the employ of the department or a duly authorized insurance company as provided
in 
Section 204 of the Labor Law of the State of New York. Equipment having an input of not more than 350,000 Btu/h 
(103 kW) shall be exempt from this requirement. Where field assembly of pressure vessels or boilers is required, a
copy of 
the completed H
-
2
, P
-
2 or U
-
1 Manufacturer’s Data Report and the completed Appendix C of ASME CSD
-
1 
required by the 
ASME Boiler and Pressure Vessel Code
shall be submitted to the 
department
.
1011.1.1 Fitness for service. 
When a boiler or pressure vessel has exceeded its us
eful life or has been subjected to 
an event that may have impacted the integrity of the pressure vessel, the department may require that a fitness for 
service study be completed. The study shall be completed in accordance with the 
National Board Inspection
Code
Part 2, Section 4, and documented in accordance with the National Board 403 form.
‡‡‡ Chapter 10 was amended by 
Local Law 
77 
of 2023
. This law has an effective
date of June 10, 2023.
CHAPTER 10
BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION MC 1001
GENERAL
1001.1 Scope.
This chapter
shall establish the minimum safety requirements for and
shall govern the installation, 
alteration and repair of boilers, wate
r heaters and pressure vessels.
Exceptions:
1.
Pressure vessels used for unheated water supply.
2.
Portable unfired pressure vessels and Interstate 
Commerce
Commission containers.
3.
Containers for bulk oxygen and medical gas.
4.
Unfired pressure 
vessels having a volume of 5 cubic feet (0.14 m
3
) or less operating at pressures not exceed-
ing 250 pounds per square inch (psi) (1723.7 kPa) and located within occupancies of Groups B, F, H, M, R, 
S and U.
5.
Pressure vessels used in refrigeration systems 
that are regulated by Chapter 11.
6.
Pressure tanks used in conjunction with coaxial cables, telephone cables, power cables and other 
similar
humidity control systems.
7.
Any boiler or pressure vessel subject to inspection by federal inspectors.
1001.2 The
rmal safety (spill) switches.
Thermal safety (spill) switches shall be installed in accordance with Section 
801.23.3.
1001.3 Clearances. 
Minimum clearances at
boilers, water heaters and pressure vessels shall be maintained in accord-
ance with Chapter 3.
SEC
TION MC 1002
WATER HEATERS
1002.1 General.
Potable water heaters and hot water storage tanks shall be listed and labeled and installed in accord-
ance with the manufacturer’s instructions, the 
New York City 
Plumbing Code 
and this code. All water heaters shal
l be 
capable of being removed without first removing a permanent portion of the building structure. The potable water 
connections
and relief valves for all water heaters shall conform to the requirements of the 
New York City 
Plumbing 
Code
. Domestic electric water heaters shall comply with UL 174 or UL 1453. Commercial electric water heaters shall 
comply with UL 1453. Oil
-
fired water heaters shall comply with UL 732. Approval for oil
-
fired water heaters 
350,000 
Btu/h input (103 kW) and above shall be obtained from the New York City Department of Environmental Protection. 
Thermal solar water heaters shall comply with UL 174 or UL 1453, and Chapter 14 of this code. Heat pump water 
heaters shall comply with UL 174 or UL 1995.
1002.2 Water heaters utilized for s
pace heating.
Water heaters utilized both to supply potable hot water and provide 
hot water for space
-
heating applications shall be listed and labeled for such applications by the manufacturer and shall 
be 
built in accordance with Section IV of the 
ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. Water 
heaters shall be 
installed in accordance with the manufacturer’s instructions
, the 
ASME Boiler and Pressure Vessel 
Code
and the 
New York City
Plumbing Code.
Oil
-
fired heaters shall comply with U
L 732 and shall have an “HW” 
stamp.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1002.2.1 Sizing.
Water heaters utilized for both potable water heating and space
-
heating applications shall be sized 
to prevent the space
-
heating load from diminishing the required potable water
-
heating capacity.
1002.2.
2 Temperature limitation.
Where a combination potable water
-
heating and space
-
heating system requires 
water for space heating, a temperature
actuated mixing valve complying with ASSE 1017 shall be provided to 
temper the water supplied to the potable hot wa
ter distribution system in accordance with Section 607 of the 
New 
York City Plumbing Code
.
1002.2.3 Cross
-
connection. 
Water heaters utilized for both potable hot water and hot water for space
-
heating 
applications shall have separate heating sections and co
nnections for distribution systems and shall not be cross
-
connected. The potability of the domestic water shall be maintained throughout the system in accordance with the 
New York City Plumbing Code.
1002.3 Supplemental water
-
heating devices.
Potable 
water
-
heating devices that utilize refrigerant
-
to
-
water heat 
exchangers shall be approved and installed in accordance with the 
New York City 
Plumbing Code
, the applicable 
provisions of the 
New York City Energy Conservation Code
and the manufacturer’s
instructions.
SECTION MC 1003
PRESSURE VESSELS
1003.1 General.
All pressure vessels shall be constructed and certified in accordance with the 
ASME Boiler and 
Pressure Vessel Code
, and shall 
bear the label of an approved agency. Pressure vessels shall 
be in
stalled in accordance 
with the manufacturer’s
instructions and nationally recognized standards. Directly fired pressure vessels shall meet 
the requirements of Section 1004.
1003.2 Piping.
All piping materials, fittings, joints, 
connections
and devices asso
ciated with systems utilized in 
con-
junction
with pressure vessels shall be designed for the specific application and shall 
comply with the 
ASME Boiler 
and Pressure Vessel Code
and this code
.
1003.3 Welding.
Welding on pressure vessels shall be performed by
welders
certified in 
compliance with nationally 
recognized standards, including the
National Board Inspection Code
and 
ASME Boiler and Pressure Vessel Code
, 
Section 
IX. Such welders shall also comply with 12 NYCRR 4
-
6.2, and 12 NYCRR 14
-
3.3 through 14
-
3.1
8.
SECTION 
MC 
1004
BOILERS
1004.1 Standards.
Boilers shall be designed, constructed and certified in accordance with the 
ASME Boiler and Pres-
sure Vessel Code
, Section I or IV, and 12 NYCRR Parts 4 and 14. Controls and safety devices for boilers with 
fuel 
input ratings of 12,500,000 Btu/h (3663 kW) or less shall meet the requirements of ASME CSD
-
1. Controls and safety 
devices for boilers with inputs greater than 12,500,000 Btu/h (3663 kW) shall meet the requirements of NFPA 85. 
Packaged oil
-
fired boile
rs shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be 
listed and labeled in accordance with UL 834.
Approval for oil
-
fired boilers 350,000 Btu/h input (102.6 kW) and 
above shall be obtained from the New York City Depa
rtment of Environmental Protection.
1004.1.1 Field erected boilers requirements. 
Field erected boiler installations shall comply with the following
:
1.
The vessel erector shall hold the appropriate ASME stamp for vessel construction.
2.
The licensed instal
ler is responsible for the installation of all controls and burners which shall be designed 
and constructed in accordance with the requirements of ASME CSD
-
1 and, as applicable, the 
ASME Boiler 
and Pressure Vessel Code
, 12 NYCRR Parts 4 and 14, and NFPA 85
.
3.
The New York City Department of Environmental Protection shall approve the installation of the boiler and 
burner for compatibility, controls and safety devices.
4.
Boiler vessels shall comply with one of the following listings:
4.1.
UL 726 or UL 795 a
s applicable; or
BOILERS, WATER HEATERS AND PRESSURE VESSELS
4.2.
UL 2106.
Exception:
Unlisted equipment shall obtain approval from the department.
5.
Controls and safety devices shall be tested and inspected in accordance with ASME CSD
-
1 and, as applicable, 
the 
ASME Boiler and Pressure Vessel Code
,
12 NYCRR Parts 4 and 14, and NFPA 85. Testing and inspection 
shall be performed by the burner manufacturer’s authorized representative in the presence of the licensed 
installer. 
6.
Inspection of the installed boiler assembly shall be performed by the dep
artment.
1004.2 Installation.
In addition to the requirements of this code, the installation of boilers shall conform to the 
man-
ufacturer’s
instructions. Operating instructions of a permanent type shall be 
located in
the boiler
room and readily 
accessible
.
Boilers shall have all controls set, adjusted and tested by the installer. The manufacturer’s rating data and 
the nameplate shall be attached to the boiler.
1004.3 Working clearance.
Clearances shall be maintained around boilers, generators, heaters, tanks and related 
equipment and appliances so as to permit inspection, servicing, repair, replacement and visibility of all gauges. When 
boilers are installed or replaced, clearance shall 
be provided to allow access for maintenance and repair
per the boiler’s 
listing and manufacturer’s instructions.
Passageways 
for inspection 
around all sides of boilers shall have an unob-
structed width of not less than 18 inches 
(
457.2
mm) 
unless 
the boiler
’s listing or department approval or manufac-
turer’s instructions state 
otherwise.
1004.3.1 Top clearance.
Clearances from the tops of boilers to the ceiling or other overhead obstruction shall be 
in accordance with Table 1004.3.1.
TABLE 1004.3.1
BOILER TOP
CLEARANCES
BOILER TYPE
MINIMUM 
CLEARANCES FROM 
TOP OF BOILER TO 
CEILING OR OTHER 
OVERHEAD 
OBSTRUCTION (feet)
All boilers with manholes on top of the 
boiler except where a greater clearance is 
required in this table.
3
All boilers without 
manholes on top of 
the boiler except high
-
pressure steam 
boilers and where a greater clearance is 
required in this table.
2
High
-
pressure steam boilers with steam 
generating capacity not exceeding 5,000 
pounds per hour.
3
High
-
pressure steam 
boilers with steam 
generating capacity exceeding 5,000 
pounds per hour.
7
High
-
pressure steam boilers having heat-
ing surface not exceeding 1,000 square 
feet.
3
High
-
pressure steam boilers having heat-
ing surface in excess of 1,000 square 
feet.
7
High
-
pressure steam boilers with input 
not exceeding 5,000,000 Btu/h.
3
BOILERS, WATER HEATERS AND PRESSURE VESSELS
High
-
pressure steam boilers with input in 
excess of 5,000,000 Btu/h.
7
Steam
-
heating boilers and hot water
-
heating boilers with input exceeding 
5,000,000 Btu/h.
3
Steam
-
heating boilers exceeding 5,000 
pounds of steam per hour.
3
Steam
-
heating boilers and hot water
-
heating boilers having heating surface 
exceeding 1,000 square feet.
3
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m
2
, 1 pound per hour = 0.4536
kg/h, 1 Btu/hr = 0.293 W.
1004.4 Mounting.
Equipment
and appliances
shall be set or mounted on a level base capable of supporting and dis-
tributing the weight contained thereon. Boilers, tanks and equipment shall be 
securely anchored to the structure. 
Equ
ipment and appliances requiring vibration isolation shall be installed as designed by a registered design profes-
sional
in accordance with the manufacturer’s instructions.
1004.5 Floors.
Boilers shall be mounted on floors of noncombustible 
construction, unless listed for mounting on 
combustible flooring. Vibration isolation shall be in accordance with Section 313. In buildings with residential occu-
pancies, boilers shall be installed in accordance with the requirements of Section 313.
1004.6 
Boiler rooms and enclosures.
Boiler rooms and enclosures and access thereto shall comply with Chapters 5 
and 10 of the 
New York City 
Building Code
and Chapter 3 of this code. Boiler rooms shall be equipped with a floor 
drain or other approved means for 
disposing
of liquid waste
in accordance with the 
New York City Plumbing Code
.
1004.7 Operating adjustments and instructions.
Hot water and steam boil
ers shall have all operating and safety 
controls set and operationally tested by the installing contractor. A 
complete
control diagram and boiler operating 
instructions shall be furnished by the installer for each installation.
A complete control diagram o
f a permanent type 
shall be located in the boiler room and shall be readily accessible.
1004.8 Burner controls.
Gas and oil modulating burners shall be provided with burner controls (oil and gas equiv-
alent ratings) in accordance with ASME CSD
-
1 and NFPA 85
.
1004.9 Conversion burners. 
Conversion burners shall be installed in accordance with ANSI Z21.8.
SECTION MC 1005
BOILER CONNECTIONS
1005.1 Valves.
Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple 
boil
er or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in 
the 
supply
and return piping.
Exception: 
Shutoff valves are not required in a system 
having
a single low
-
pressure steam boiler
of 350,000 Btu
/h 
(103 kW) output or less
.
1005.2 Potable water supply.
The water supply to all boilers, including but not limited to backflow prevention, shall 
be connected in accordance with the 
New
York City 
Plumbing Code
. 
SECTION MC 1006
SAFETY AND PRESSURE 
RELIEF VALVES
AND CONTROLS
1006.1 Safety valves for steam boilers. 
Steam boilers shall be protected with a safety valve 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1006.2 Safety relief valves for hot water boilers.
Hot water 
boilers shall be protected with a safety relief valve 
in 
accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1
.
1006.3 Pressure relief for pressure vessels. 
Pressure vessels
shall be protected with a pressure relief valve or 
pres-
sure
-
limit
ing device as required by the manufacturer’s instructions for the pressure vessel and 
in accordance with the 
ASME Boiler and Pressure Vessel Code
or ASME CSD
-
1.
1006.4 Standards of safety and safety relief valves.
Safety and safety relief valves shall be l
isted and labeled, and 
shall have a minimum rated capacity for the equipment or appliances served. Safety and safety relief valves shall be 
set at not greater than the nameplate pressure rating of the boiler or pressure vessel and shall be in accordance wi
th 
the
ASME Boiler and Pressure Vessel Code
or the ASME CSD
-
1
.
1006.5 Installation.
Safety or relief valves shall be installed directly into the safety or relief valve opening on the 
boiler or pressure vessel. Valves shall not be located on either side of a safety or relief valve connection. The relief 
valve drain shall 
discharge by gravi
ty to a nonhazardous point of discharge without obstruction.‡
1006.6 Safety and relief valve discharge.
Safety and relief valve discharge pipes shall be of rigid pipe that is approved 
for the temperature of the system. The discharge pipe shall
, at a minimu
m,
be the same diameter as the safety or relief 
valve outlet. Safety and relief valve discharge pipes shall be properly supported to prevent stress on the valve and 
vessel. Safety and relief valves shall not discharge so as to be a hazard, a potential caus
e of damage or otherwise a 
nuisance. 
Discharge of hazardous materials must be properly contained in a method approved by the department. 
High
-
pressure
-
steam safety valves shall be vented to the outside of the structure. Where a low
-
pressure safety valve 
or
a relief valve discharges to the drainage system, the installation shall conform to the 
New York City 
Plumbing Code
.
1006.7 Boiler safety devices.
Boilers shall be equipped with controls and limit devices as required by the manufac-
turer’s instructions and
the conditions of the listing.
1006.8 Electrical requirements.
The power supply to the electrical control system shall be from a two
-
wire branch 
circuit
that has a grounded conductor, or from an isolation 
trans
-
former
with a two
-
wire secondary. Where an i
solation 
transformer is provided, one conductor of the secondary 
winding
shall be grounded. Control voltage shall not exceed 
150 volts nominal, line to line. Control and limit devices shall 
interrupt
the ungrounded side of the circuit. A means 
of manually 
disconnecting the control circuit shall be provided and controls shall be arranged so that when deener-
gized, the burner shall be inoperative. Such disconnecting means shall be capable of being locked in the off position 
and shall be provided with ready acc
ess.
1006.8.1 Remote control (shutdown).
A remote control shall be provided to stop the flow of oil and/or gas and 
combustion air to any burner or fuel
-
burning internal combustion equipment. Such a control shall be provided 
along every means of egress from
the room in which the burner or equipment is located. Each remote control shall 
be located outside of, but as close as practicable to the burner or equipment room itself and shall be labeled: 
“REMOTE CONTROL FOR BURNER.”
Exception:
Where an outside locati
on is impracticable, the remote control shutdown may be provided immedi-
ately inside the room in which the burner or equipment is located.
Such location must be accessible at all times.
1006.9 Carbon monoxide detectors.
Carbon monoxide detectors shall be p
rovided in all fuel
-
fired appliance rooms 
to detect the level of carbon monoxide in the room and signal an alarm.    Such detectors shall be listed and installed 
in accordance with Chapter 9 of the 
New York City Building Code
.
SECTION 
MC 
1007
BOILER 
LOW
-
WATER CUTOFF
1007.1 General.
Steam and hot water boilers shall be protected with 
dual
low
-
water cutoff control, with each control 
independently piped to the pressure vessel in accordance with ASME CSD
-
1. For hydronic boilers, the low
-
water cut 
out may 
be located in the supply piping above the boiler before any intervening valve. A flow
-
sensing control installed 
in accordance with ASME CSD
-
1 shall be considered a low
-
water cutoff for the purposes of this section. 
Exception: 
Hot water
boilers 
located wit
hin a dwelling unit supplying only 
that 
unit and having a total heat input
of 
less than 400,000 Btu/h (117.2 kW) may be
protected 
by only one low
-
water cutoff 
control.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1007.2 Operation. 
Low
-
water cutoff controls and flow
-
sensing controls required by Section 1007.1 shall automati-
cally stop the combustion operation of the appliance when the water level drops below the lowest safe water level as 
established by the manufacturer 
and in accordance with ASME CSD
-
1, 
or when water circulation stops, respectively.
10
07.3 Low
-
water cut out maintenance and testing.
Low
-
water cut outs shall be maintained in accordance with 
ASME CSD
-
1 and the manufacturer’s specifications. An operator shall test low
-
water cut outs as follows: (1) high 
pressure steam boilers every shift, (
2) low pressure steam boilers daily and (3) hot water boilers monthly. Slow drain 
tests shall be conducted for steam boilers every six months.
Every year, low
-
water cut outs and associated piping for 
steam boilers shall be opened, cleaned and inspected. 
Re
cords of all testing, cleaning, and inspection required by this 
section shall be maintained, and made available to the department upon request. 
SECTION MC 1008
BOILER BLOWOFF/BLOWDOWN VALVES
1008.1 General.
Every boiler
shall be equipped with blowoff
/blow
down
valve(s). The valve(s) shall be installed in 
the 
openings
provided on the boiler. The minimum 
quantity and 
size of the valve(s) and associated piping shall be the 
quantity and 
size specified by the boiler manufacturer or the 
quantity and size of the boiler blowoff
/blowdown 
valve 
opening. Where the maximum allowable working pressure of the boiler exceeds 15 psig (103.4 kPa), two bottom 
blowoff valves shall be provided consisting 
of either two slow
-
opening valves in series or one quick
-
opening valve 
and one slow
-
opening valve in series, with the quick
-
opening valve installed closest to the boiler.
1008.2 Discharge.
Blowoff
/blowdown
valves shall discharge to a safe place of disposal. Where discharging to the 
drainage system, the installation shall conform to the 
New York City 
Plumbing Code.
1008.3 Maintenance.
Blowdown lines shall be inspected annually to verify they are free of deposits and in good 
working condition.
SECTION MC 1009
HOT WATER BOILER EXPANSION TANK
1009.1 Where required.
An expansion tank shall be installed in every hot water system. For multiple boiler installa-
tions, not less than one expansion tank is required. Expansion tanks shall be of the closed or open type. Tanks shall 
be rated for the pressure of the hot water system.
Lockable shutoff valves shall be installed at connections to all 
expansion tanks. Valves shall remain locked in the open position.
1009.2 Closed
-
type expansion tanks.
Closed
-
type expansion tanks shall be installed in accordance with the manu-
facturer’s instructions. Expansion tanks for systems designed to have an operating pressure in excess of 30 psi (205.8 
kPa) shall be constructed and certified in accordance with the 
ASME Boiler and Pressure Vessel Code
. The size of the 
tank shall be based on the capacity of the hot
-
water
-
heating system. The minimum size of the tank shall be determined 
in accordance with the following equation where all necessary
information is known:
V
t
  =  
(
0
.
00041T
−0
.
0466
)
V
s
�
P
a
P
f
�
−�
P
a
P
o
�
(Equation 10
-
1)
For SI:
V
t
  =  
(
0.
000738T
−
0.
03348
)
V
s
�
P
a
P
f
�−�
P
a
P
o
�
where:
V
t
= 
Minimum volume of tanks (gallons) (L).
V
s
= 
Volume of system, not including expansion tanks
(gallons) (L).
T 
= 
Average operating temperature (
°
F) (
°
C).
P
a
= 
Atmospheric pressure (psi) (kPa).
BOILERS, WATER HEATERS AND PRESSURE VESSELS
P
f
= 
Fill pressure (psi) (kPa).
P
o
= 
Maximum operating pressure (psi) (kPa).
Where all necessary information is not known, the minimum size of the tank shall be 
determined from Table 1009.2.
TABLE 1009.2
CLOSED
-
TYPE EXPANSION TANK SIZING
SYSTEM VOLUME
IN GALLONS
TANK CAPACITIES IN GALLONS
Pressurized
Diaphragm Type
Nonpressurized
Type
100
9
15
200
17
30
300
25
45
400
33
60
500
42
75
1,000
83
150
2,000
165
300
For SI: 1 gallon = 3.795 L.
1009.3 Open
-
type expansion tanks.
Open
-
type expansion tanks shall be located not less than 4 feet (1219.2 mm) 
above the highest heating element. The tank shall be adequately sized for the hot water system. An overflow with a 
minimum 
diameter
of 1 inch (25.4 mm) shall be installed at the to
p of the tank. The overflow shall discharge to the 
drainage system in 
accordance
with the 
New York City 
Plumbing Code.
SECTION MC 1010
GAUGES
1010.1 Hot water boiler gauges.
Every hot water boiler shall have a pressure gauge and a temperature gauge, or a 
c
ombination pressure and temperature gauge. The gauges shall indicate the temperature and pressure within the normal 
range of the system’s operation.
1010.2 Steam boiler gauges.
Every steam boiler shall have a water
-
gauge glass and a pressure gauge with a s
iphon. 
The pressure gauge shall indicate the pressure within the normal range of the system’s operation.
1010.2.1 Water
-
gauge glass.
The gauge glass shall be installed in accordance with the 
ASME Boiler and Pressure 
Vessel Code 
or ASME CSD
-
1.
SECTION MC 1011
TESTS
1011.1 Tests.
Upon completion of the assembly and 
installation
of boilers and pressure vessels, acceptance tests shall 
be conducted in accordance with the requirements of the 
ASME Boiler and Pressure Vessel Code
. Boilers shall not 
be placed in operation upon completion of construction until they have been inspected
a
nd 
tested and a certificate of 
compliance has been issued by the commissioner. All final inspections and
tests 
for boilers shall be witnessed by a 
qualified boiler inspector in the employ of the department or a duly authorized insurance company as provided
in 
Section 204 of the Labor Law of the State of New York. Equipment having an input of not more than 350,000 Btu/h 
(103 kW) shall be exempt from this requirement. Where field assembly of pressure vessels or boilers is required, a
copy of 
the completed H
-
2
, P
-
2 or U
-
1 Manufacturer’s Data Report and the completed Appendix C of ASME CSD
-
1 
required by the 
ASME Boiler and Pressure Vessel Code
shall be submitted to the 
department
.
1011.1.1 Fitness for service. 
When a boiler or pressure vessel has exceeded its us
eful life or has been subjected to 
an event that may have impacted the integrity of the pressure vessel, the department may require that a fitness for 
service study be completed. The study shall be completed in accordance with the 
National Board Inspection
Code
Part 2, Section 4, and documented in accordance with the National Board 403 form.
BOILERS, WATER HEATERS AND PRESSURE VESSELS
1011.2 Test gauges.
An indicating test gauge shall be 
connected
directly to the boiler or pressure vessel where it is 
visible to the operator throughout the duration of
the test. The pressure gauge scale shall be graduated over a range of 
not less than one and one
-
half times and not greater than four times the maximum test pressure. Gauges utilized for 
testing shall be calibrated and certified 
annually in accordance with
ASME B40.100 
by the test operator.
‡‡‡
1011.3 Periodic boiler inspections.
Periodic boiler inspections shall be performed in accordance with Article 
303 
of Chapter 3 
of Title 28 
of the 
Administrative Code 
and Section 1007.3 of this code. In 
addition, boiler inspec-
tions shall:
1.
Be completed in accordance with the 
National Board Inspection Code
.
2.
Include the review of testing documentation for all controls and safety devices.
3.
Verify that the flue connection from the boiler to the chimney
is properly sealed and in good working condition.
4.
Verify that the combustion air system as originally designed is operational.
5.
Verify that the High Pressure Operators’ licenses are current and that Low Pressure Operators are qualified per 
New York S
tate requirements.
6.
Include a permanent record of the visit.
7.
Be subject to the quality control measures of the department. 
1011.4
Pressurized systems containing hazardous materials.
Any pressurized system that contains hazardous ma-
terials or presents
a physical hazard by release shall be pre
-
approved for installation, subject to testing, and subject to 
inspection by the department.
1011.5 Nondestructive examination. 
When required by the department, the nondestructive examination (NDE) re-
quirements, in
cluding technique, extent of coverage, procedures, personnel qualification, and acceptance criteria, shall 
be performed in accordance with the applicable provisions of the edition of the code of construction for the pressure
-
vessel in effect at the time of
installation. Weld repairs and alterations shall be subject to the same nondestructive 
examination requirements. Where this is not possible or practicable, alternative NDE methods acceptable to the in-
spector and the department may be used.
SECTION MC 1012
MAXIMUM TEMPERATURE
1012.1 Maximum temperature.
Maximum indoor temperature in spaces surrounding boilers, water heaters, and 
pressure vessels shall not exceed the operational temperature of the installed equipment or 104°F (40°C).