Text/009.txt

‡‡‡ Chapter 5 was amended by 
Local Law 
77 
of 2023
. This law has an effective
 date of June 10, 2023.
CHAPTER 5
WATER HEATERS
SECTION 
PC 
501
GENERAL
501.1 Scope. 
The provisions of this chapter shall govern the materials, design and installation of water heaters and the 
related safety devices and appurtenances.
501.2 Water heaters utilized for space 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 o
f the ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. They 
shall be 
installed in accordance with the manufacturer’s instructions
, the ASME 
Boiler and Pressure Vessel Code
and the 
New York City
Mechanical Code
.
501.2.1 Cross 
connection. 
Water heaters utilized for both potable hot water and hot water for space heating appli-
cations shall have separate heating sections and connections for distribution systems and shall not be cross
-
con-
nected. The potability of the domestic water 
shall be maintained throughout the system in accordance with Chapter 
6.
501.2.2 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 pota
ble water
-
heating capacity.
501.2.3 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 w
ater supplied to the potable hot water
distribution system in accordance with Section 607. 
501.3 Drain valves. 
Drain valves for emptying shall be installed at the bottom of each tank
-
type water heater and hot 
water storage tank. The drain valve inlet shal
l be not less than 
3
/
4
-
inch (19 mm) nominal iron pipe size and the outlet 
shall be provided with male garden hose threads.
501.4 Location. 
Water heaters and storage tanks shall be located and connected so as to provide access
for observa-
tion, maintenance, 
servicing and replacement. 
501.5 Water heater labeling. 
Water heaters shall be third
-
party certified.
501.6 Water temperature control in piping from tankless heaters. 
The temperature of water from tankless water 
heaters shall be not greater than 
140°F (60°C) where intended for domestic uses. This provision shall not supersede 
the requirement for protective shower valves in accordance with Section 424.3.
501.7 Pressure marking of storage tanks. 
Storage tanks and water heaters installed for domestic
hot water shall have 
the maximum allowable working pressure clearly and indelibly stamped in the metal or marked on a plate welded 
thereto or otherwise permanently attached. Such markings shall be in an accessible position outside of the tank so as 
to mak
e inspection or reinspection readily possible.
501.8 Temperature controls.
Hot water supply systems shall be equipped with automatic temperature controls capa-
ble of adjustments from the lowest to the highest acceptable temperature settings for the intended
temperature operat-
ing range.
501.9 Supplemental water
-
heating devices. 
Potable water
-
heating devices that utilize refrigerant
-
to
-
water heat ex-
changers shall be approved and installed in accordance with this code, the applicable provisions of the 
New York 
City 
Energy Conservation Code
and the manufacturer’s instructions.
SECTION 
PC 
502
INSTALLATION
WATER HEATERS
‡‡‡
502.1 General. 
Water heaters shall be installed in accordance with the manufacturer’s instructions. Oil
-
fired 
water heaters shall conform to the requirements
of this code, the 
New York City
Mechanical Code
, and shall comply 
with UL 732. Approval for oil
-
fired water heaters 350,000 Btu/h input (102
.
5 kW) and above shall be obtained from 
the New York City Department of Environmental Protection. Electric water he
aters shall conform to the requirements 
of this code and provisions of 
the 
New York City Electrical Code
. 
Domestic electric water heaters shall comply with 
UL 174 or UL 1453. Commercial electric water heaters shall comply with UL 1453. Gas
-
fired water heat
ers shall 
conform to the requirements of the 
New York City
Fuel Gas
Code
. All water heaters shall conform to the 
New York 
City Energy Conservation 
Code
.
502.1.1 Elevation and protection. 
Elevation of water heater ignition sources and mechanical damage protection 
requirements for water heaters shall be in accordance with the 
New York City 
Mechanical Code 
and the 
New York 
City 
Fuel Gas Code
.
502.2 Rooms used as a plenum. 
Water heaters using 
solid, liquid or gas fuel shall not be installed in a room containing 
air
-
handling machinery 
where
such room is used as a plenum.
502.3 Water heaters installed in attics.
Water heaters installed in attics shall be electric. 
Attics containing a water 
heater
shall be provided with an opening and unobstructed passageway large enough to allow removal of the water 
heater. The passageway shall be not less than 30 inches (762 mm) 
in height
and 22 inches (559 mm) in width and not 
more than 20 feet (6096 mm) in leng
th when measured along the centerline of the passageway from the opening to 
the water heater. The passageway shall have continuous solid flooring not less than 24 inches (610 mm) in width. A 
level service space not less than 30 inches (762 mm) in length an
d 30 inches (762 mm) 
in width
shall be present at the 
front or service side of the water heater. Dimensions of the clear access opening shall be 
not less than 20 inches by 
30 inches (508 mm by 762 mm) and shall be large enough to allow removal of the water
heater.
502.4 Seismic supports. 
Where earthquake loads are applicable in accordance with the 
New York City
Building Code
, 
water heater supports shall be designed and installed for the seismic forces in accordance with the 
New York City 
Building Code
.
502.
5 Clearances for maintenance and replacement. 
Appliances shall be provided with access
for inspection, ser-
vice, repair and replacement without disabling the function of a fire
-
resistance
-
rated assembly or removing permanent 
construction, other appliances o
r any other piping or ducts not connected to the appliance being inspected, serviced, 
repaired or replaced. A level working space not less than 30 inches in length and 30 inches in width (762 mm by 762 
mm) shall be provided in front of the control side to 
service an appliance.
SECTION 
PC 
503
CONNECTIONS
503.1 Cold water line valve. 
The cold water branch
line from the main water supply line to each hot water storage 
tank or water heater shall be provided with a valve, located near the equipment and serving o
nly the hot water storage 
tank or water heater. The valve shall not interfere or cause a disruption of the cold water supply to the remainder of 
the cold water system. The valve shall be provided with access
on the same floor level as the water heater serv
ed.
503.2 Water circulation. 
The method of connecting a circulating water heater to the tank shall provide proper circu-
lation of water through the water heater. The pipe or tubes required for the installation of appliances that will draw 
from the water hea
ter or storage tank shall comply with the provisions of this code for material and installation.
SECTION 
PC 
504
SAFETY DEVICES
504.1 Antisiphon devices. 
An approved
means, such as a cold water “dip” tube with a hole at the top or a vacuum 
relief valve installed in the cold water supply line above the top of the heater or tank, shall be provided to prevent 
siphoning of any storage water heater or tank.
504.2 Vacuum rel
ief valve. 
Bottom fed water heaters and bottom fed tanks connected to water heaters shall have a 
vacuum relief valve installed. The vacuum relief valve shall comply with ANSI Z21.22.
WATER HEATERS
504.3 Shutdown. 
A means for disconnecting an electric hot water supply system from its energy supply shall be 
provided in accordance with 
the 
New York City Electrical Code
. A separate valve shall be provided to shut off the 
energy fuel supply to all other types of hot wat
er supply systems in accordance with the 
New York City Fuel Gas Code
and 
New York City Mechanical Code
.
504.4 Relief valve.
Storage
water heaters operating above atmospheric pressure shall be provided with an approved, 
self
-
closing (levered) pressure relie
f valve and temperature relief valve or combination thereof. The relief valve shall 
conform to ANSI Z21.22. The relief valve shall not be used as a means of controlling thermal expansion.
504.4.1 Installation. 
Such valves shall be installed in the shell of
the storage water heater tank. Temperature relief 
valves shall be so located in the tank as to be actuated by the water in the top 6 inches (152 mm) of the tank served. 
For installations with separate storage tanks, the approved, self
-
closing (levered) pr
essure relief valve and temper-
ature relief valve or combination thereof conforming to ANSI Z21.22, shall be installed on both the 
storage
water 
heater and
storage tank. There shall not be a check valve or shutoff valve between a relief valve and the heater
or 
tank served.
504.5 Relief valve approval. 
Temperature and pressure relief valves, or combinations thereof, and energy cutoff 
devices shall bear the label of an approved
agency and shall have a temperature setting of not more than 210°F (99°C) 
and a pre
ssure setting not exceeding the tank or water heater manufacturer’s rated working pressure. The relieving 
capacity of each pressure relief valve and each temperature relief valve shall equal or exceed the heat input to the 
water heater or storage tank.
504
.6 Requirements for discharge piping. 
The discharge piping serving a pressure relief valve, temperature relief 
valve or combination thereof shall:
1.
Not be directly connected to the drainage system.
2.
Discharge through an air gap
located in the same ro
om as the water heater.
3.
Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
4.
Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
5.
Discharge in a manner that does not cause personal injury or structural damage.
6.
Discharge to a termination point that is readily observable by the building occupants.
7.
Not be trapped.
8.
Be installed so as to flow by gravity.
9.
Terminate not more
than 6 inches (152 mm) above and not less than two times the discharge pipe diameter 
above the floor or flood level rim of the waste receptor.
10.
Not have a threaded connection at the end of such piping.
11.
Not have valves or tee fittings.
12.
Be constr
ucted of those materials listed in Section 605.4 or materials tested, rated and approved
for such use 
in accordance with ASME A112.4.1.
504.7 Required pan. 
Where a storage tank
-
type water heater or a hot water storage tank is installed in a location 
where water leakage 
from
the 
tank
will cause damage, the tank shall be installed in a galvanized steel pan having a 
material thickness of not less than 0.0236 inc
h (0.6010 mm) (No. 24 gage), or other pans approved
for such use.
504.7.1 Pan size and drain. 
The pan shall be not less than 1
1
/
2
inches (38 mm) in depth and shall be of sufficient 
size and shape to receive all dripping or condensate from the tank or water
heater. The pan shall be drained by an 
indirect waste pipe having a diameter of not less than 
3
/
4
inch (19 mm). Piping for safety pan drains shall be of 
those materials listed in Table 605.4.
Exception:
A pan drain shall not be required for a replacement 
water heater where a pan drain was not previously 
installed, provided that a leak detector is installed within the pan.
504.7.2 Pan drain termination. 
The pan drain shall extend full size and terminate over a suitably located indirect 
waste receptor or flo
or drain or extend to the exterior of the building and terminate not less than 6 inches (152 mm) 
and not more than 24 inches (610 mm) above the adjacent ground 
surface at a point that is readily observable by 
the building occupants
. 
‡‡‡ Chapter 5 was amended by 
Local Law 
77 
of 2023
. This law has an effective
 date of June 10, 2023.
CHAPTER 5
WATER HEATERS
SECTION 
PC 
501
GENERAL
501.1 Scope. 
The provisions of this chapter shall govern the materials, design and installation of water heaters and the 
related safety devices and appurtenances.
501.2 Water heaters utilized for space 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 o
f the ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. They 
shall be 
installed in accordance with the manufacturer’s instructions
, the ASME 
Boiler and Pressure Vessel Code
and the 
New York City
Mechanical Code
.
501.2.1 Cross 
connection. 
Water heaters utilized for both potable hot water and hot water for space heating appli-
cations shall have separate heating sections and connections for distribution systems and shall not be cross
-
con-
nected. The potability of the domestic water 
shall be maintained throughout the system in accordance with Chapter 
6.
501.2.2 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 pota
ble water
-
heating capacity.
501.2.3 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 w
ater supplied to the potable hot water
distribution system in accordance with Section 607. 
501.3 Drain valves. 
Drain valves for emptying shall be installed at the bottom of each tank
-
type water heater and hot 
water storage tank. The drain valve inlet shal
l be not less than 
3
/
4
-
inch (19 mm) nominal iron pipe size and the outlet 
shall be provided with male garden hose threads.
501.4 Location. 
Water heaters and storage tanks shall be located and connected so as to provide access
for observa-
tion, maintenance, 
servicing and replacement. 
501.5 Water heater labeling. 
Water heaters shall be third
-
party certified.
501.6 Water temperature control in piping from tankless heaters. 
The temperature of water from tankless water 
heaters shall be not greater than 
140°F (60°C) where intended for domestic uses. This provision shall not supersede 
the requirement for protective shower valves in accordance with Section 424.3.
501.7 Pressure marking of storage tanks. 
Storage tanks and water heaters installed for domestic
hot water shall have 
the maximum allowable working pressure clearly and indelibly stamped in the metal or marked on a plate welded 
thereto or otherwise permanently attached. Such markings shall be in an accessible position outside of the tank so as 
to mak
e inspection or reinspection readily possible.
501.8 Temperature controls.
Hot water supply systems shall be equipped with automatic temperature controls capa-
ble of adjustments from the lowest to the highest acceptable temperature settings for the intended
temperature operat-
ing range.
501.9 Supplemental water
-
heating devices. 
Potable water
-
heating devices that utilize refrigerant
-
to
-
water heat ex-
changers shall be approved and installed in accordance with this code, the applicable provisions of the 
New York 
City 
Energy Conservation Code
and the manufacturer’s instructions.
SECTION 
PC 
502
INSTALLATION
WATER HEATERS
‡‡‡
502.1 General. 
Water heaters shall be installed in accordance with the manufacturer’s instructions. Oil
-
fired 
water heaters shall conform to the requirements
of this code, the 
New York City
Mechanical Code
, and shall comply 
with UL 732. Approval for oil
-
fired water heaters 350,000 Btu/h input (102
.
5 kW) and above shall be obtained from 
the New York City Department of Environmental Protection. Electric water he
aters shall conform to the requirements 
of this code and provisions of 
the 
New York City Electrical Code
. 
Domestic electric water heaters shall comply with 
UL 174 or UL 1453. Commercial electric water heaters shall comply with UL 1453. Gas
-
fired water heat
ers shall 
conform to the requirements of the 
New York City
Fuel Gas
Code
. All water heaters shall conform to the 
New York 
City Energy Conservation 
Code
.
502.1.1 Elevation and protection. 
Elevation of water heater ignition sources and mechanical damage protection 
requirements for water heaters shall be in accordance with the 
New York City 
Mechanical Code 
and the 
New York 
City 
Fuel Gas Code
.
502.2 Rooms used as a plenum. 
Water heaters using 
solid, liquid or gas fuel shall not be installed in a room containing 
air
-
handling machinery 
where
such room is used as a plenum.
502.3 Water heaters installed in attics.
Water heaters installed in attics shall be electric. 
Attics containing a water 
heater
shall be provided with an opening and unobstructed passageway large enough to allow removal of the water 
heater. The passageway shall be not less than 30 inches (762 mm) 
in height
and 22 inches (559 mm) in width and not 
more than 20 feet (6096 mm) in leng
th when measured along the centerline of the passageway from the opening to 
the water heater. The passageway shall have continuous solid flooring not less than 24 inches (610 mm) in width. A 
level service space not less than 30 inches (762 mm) in length an
d 30 inches (762 mm) 
in width
shall be present at the 
front or service side of the water heater. Dimensions of the clear access opening shall be 
not less than 20 inches by 
30 inches (508 mm by 762 mm) and shall be large enough to allow removal of the water
heater.
502.4 Seismic supports. 
Where earthquake loads are applicable in accordance with the 
New York City
Building Code
, 
water heater supports shall be designed and installed for the seismic forces in accordance with the 
New York City 
Building Code
.
502.
5 Clearances for maintenance and replacement. 
Appliances shall be provided with access
for inspection, ser-
vice, repair and replacement without disabling the function of a fire
-
resistance
-
rated assembly or removing permanent 
construction, other appliances o
r any other piping or ducts not connected to the appliance being inspected, serviced, 
repaired or replaced. A level working space not less than 30 inches in length and 30 inches in width (762 mm by 762 
mm) shall be provided in front of the control side to 
service an appliance.
SECTION 
PC 
503
CONNECTIONS
503.1 Cold water line valve. 
The cold water branch
line from the main water supply line to each hot water storage 
tank or water heater shall be provided with a valve, located near the equipment and serving o
nly the hot water storage 
tank or water heater. The valve shall not interfere or cause a disruption of the cold water supply to the remainder of 
the cold water system. The valve shall be provided with access
on the same floor level as the water heater serv
ed.
503.2 Water circulation. 
The method of connecting a circulating water heater to the tank shall provide proper circu-
lation of water through the water heater. The pipe or tubes required for the installation of appliances that will draw 
from the water hea
ter or storage tank shall comply with the provisions of this code for material and installation.
SECTION 
PC 
504
SAFETY DEVICES
504.1 Antisiphon devices. 
An approved
means, such as a cold water “dip” tube with a hole at the top or a vacuum 
relief valve installed in the cold water supply line above the top of the heater or tank, shall be provided to prevent 
siphoning of any storage water heater or tank.
504.2 Vacuum rel
ief valve. 
Bottom fed water heaters and bottom fed tanks connected to water heaters shall have a 
vacuum relief valve installed. The vacuum relief valve shall comply with ANSI Z21.22.
WATER HEATERS
504.3 Shutdown. 
A means for disconnecting an electric hot water supply system from its energy supply shall be 
provided in accordance with 
the 
New York City Electrical Code
. A separate valve shall be provided to shut off the 
energy fuel supply to all other types of hot wat
er supply systems in accordance with the 
New York City Fuel Gas Code
and 
New York City Mechanical Code
.
504.4 Relief valve.
Storage
water heaters operating above atmospheric pressure shall be provided with an approved, 
self
-
closing (levered) pressure relie
f valve and temperature relief valve or combination thereof. The relief valve shall 
conform to ANSI Z21.22. The relief valve shall not be used as a means of controlling thermal expansion.
504.4.1 Installation. 
Such valves shall be installed in the shell of
the storage water heater tank. Temperature relief 
valves shall be so located in the tank as to be actuated by the water in the top 6 inches (152 mm) of the tank served. 
For installations with separate storage tanks, the approved, self
-
closing (levered) pr
essure relief valve and temper-
ature relief valve or combination thereof conforming to ANSI Z21.22, shall be installed on both the 
storage
water 
heater and
storage tank. There shall not be a check valve or shutoff valve between a relief valve and the heater
or 
tank served.
504.5 Relief valve approval. 
Temperature and pressure relief valves, or combinations thereof, and energy cutoff 
devices shall bear the label of an approved
agency and shall have a temperature setting of not more than 210°F (99°C) 
and a pre
ssure setting not exceeding the tank or water heater manufacturer’s rated working pressure. The relieving 
capacity of each pressure relief valve and each temperature relief valve shall equal or exceed the heat input to the 
water heater or storage tank.
504
.6 Requirements for discharge piping. 
The discharge piping serving a pressure relief valve, temperature relief 
valve or combination thereof shall:
1.
Not be directly connected to the drainage system.
2.
Discharge through an air gap
located in the same ro
om as the water heater.
3.
Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
4.
Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
5.
Discharge in a manner that does not cause personal injury or structural damage.
6.
Discharge to a termination point that is readily observable by the building occupants.
7.
Not be trapped.
8.
Be installed so as to flow by gravity.
9.
Terminate not more
than 6 inches (152 mm) above and not less than two times the discharge pipe diameter 
above the floor or flood level rim of the waste receptor.
10.
Not have a threaded connection at the end of such piping.
11.
Not have valves or tee fittings.
12.
Be constr
ucted of those materials listed in Section 605.4 or materials tested, rated and approved
for such use 
in accordance with ASME A112.4.1.
504.7 Required pan. 
Where a storage tank
-
type water heater or a hot water storage tank is installed in a location 
where water leakage 
from
the 
tank
will cause damage, the tank shall be installed in a galvanized steel pan having a 
material thickness of not less than 0.0236 inc
h (0.6010 mm) (No. 24 gage), or other pans approved
for such use.
504.7.1 Pan size and drain. 
The pan shall be not less than 1
1
/
2
inches (38 mm) in depth and shall be of sufficient 
size and shape to receive all dripping or condensate from the tank or water
heater. The pan shall be drained by an 
indirect waste pipe having a diameter of not less than 
3
/
4
inch (19 mm). Piping for safety pan drains shall be of 
those materials listed in Table 605.4.
Exception:
A pan drain shall not be required for a replacement 
water heater where a pan drain was not previously 
installed, provided that a leak detector is installed within the pan.
504.7.2 Pan drain termination. 
The pan drain shall extend full size and terminate over a suitably located indirect 
waste receptor or flo
or drain or extend to the exterior of the building and terminate not less than 6 inches (152 mm) 
and not more than 24 inches (610 mm) above the adjacent ground 
surface at a point that is readily observable by 
the building occupants
. 
‡‡‡ Chapter 5 was amended by 
Local Law 
77 
of 2023
. This law has an effective
 date of June 10, 2023.
CHAPTER 5
WATER HEATERS
SECTION 
PC 
501
GENERAL
501.1 Scope. 
The provisions of this chapter shall govern the materials, design and installation of water heaters and the 
related safety devices and appurtenances.
501.2 Water heaters utilized for space 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 o
f the ASME 
Boiler and Pressure Vessel Code
with an “H” code stamp. They 
shall be 
installed in accordance with the manufacturer’s instructions
, the ASME 
Boiler and Pressure Vessel Code
and the 
New York City
Mechanical Code
.
501.2.1 Cross 
connection. 
Water heaters utilized for both potable hot water and hot water for space heating appli-
cations shall have separate heating sections and connections for distribution systems and shall not be cross
-
con-
nected. The potability of the domestic water 
shall be maintained throughout the system in accordance with Chapter 
6.
501.2.2 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 pota
ble water
-
heating capacity.
501.2.3 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 w
ater supplied to the potable hot water
distribution system in accordance with Section 607. 
501.3 Drain valves. 
Drain valves for emptying shall be installed at the bottom of each tank
-
type water heater and hot 
water storage tank. The drain valve inlet shal
l be not less than 
3
/
4
-
inch (19 mm) nominal iron pipe size and the outlet 
shall be provided with male garden hose threads.
501.4 Location. 
Water heaters and storage tanks shall be located and connected so as to provide access
for observa-
tion, maintenance, 
servicing and replacement. 
501.5 Water heater labeling. 
Water heaters shall be third
-
party certified.
501.6 Water temperature control in piping from tankless heaters. 
The temperature of water from tankless water 
heaters shall be not greater than 
140°F (60°C) where intended for domestic uses. This provision shall not supersede 
the requirement for protective shower valves in accordance with Section 424.3.
501.7 Pressure marking of storage tanks. 
Storage tanks and water heaters installed for domestic
hot water shall have 
the maximum allowable working pressure clearly and indelibly stamped in the metal or marked on a plate welded 
thereto or otherwise permanently attached. Such markings shall be in an accessible position outside of the tank so as 
to mak
e inspection or reinspection readily possible.
501.8 Temperature controls.
Hot water supply systems shall be equipped with automatic temperature controls capa-
ble of adjustments from the lowest to the highest acceptable temperature settings for the intended
temperature operat-
ing range.
501.9 Supplemental water
-
heating devices. 
Potable water
-
heating devices that utilize refrigerant
-
to
-
water heat ex-
changers shall be approved and installed in accordance with this code, the applicable provisions of the 
New York 
City 
Energy Conservation Code
and the manufacturer’s instructions.
SECTION 
PC 
502
INSTALLATION
WATER HEATERS
‡‡‡
502.1 General. 
Water heaters shall be installed in accordance with the manufacturer’s instructions. Oil
-
fired 
water heaters shall conform to the requirements
of this code, the 
New York City
Mechanical Code
, and shall comply 
with UL 732. Approval for oil
-
fired water heaters 350,000 Btu/h input (102
.
5 kW) and above shall be obtained from 
the New York City Department of Environmental Protection. Electric water he
aters shall conform to the requirements 
of this code and provisions of 
the 
New York City Electrical Code
. 
Domestic electric water heaters shall comply with 
UL 174 or UL 1453. Commercial electric water heaters shall comply with UL 1453. Gas
-
fired water heat
ers shall 
conform to the requirements of the 
New York City
Fuel Gas
Code
. All water heaters shall conform to the 
New York 
City Energy Conservation 
Code
.
502.1.1 Elevation and protection. 
Elevation of water heater ignition sources and mechanical damage protection 
requirements for water heaters shall be in accordance with the 
New York City 
Mechanical Code 
and the 
New York 
City 
Fuel Gas Code
.
502.2 Rooms used as a plenum. 
Water heaters using 
solid, liquid or gas fuel shall not be installed in a room containing 
air
-
handling machinery 
where
such room is used as a plenum.
502.3 Water heaters installed in attics.
Water heaters installed in attics shall be electric. 
Attics containing a water 
heater
shall be provided with an opening and unobstructed passageway large enough to allow removal of the water 
heater. The passageway shall be not less than 30 inches (762 mm) 
in height
and 22 inches (559 mm) in width and not 
more than 20 feet (6096 mm) in leng
th when measured along the centerline of the passageway from the opening to 
the water heater. The passageway shall have continuous solid flooring not less than 24 inches (610 mm) in width. A 
level service space not less than 30 inches (762 mm) in length an
d 30 inches (762 mm) 
in width
shall be present at the 
front or service side of the water heater. Dimensions of the clear access opening shall be 
not less than 20 inches by 
30 inches (508 mm by 762 mm) and shall be large enough to allow removal of the water
heater.
502.4 Seismic supports. 
Where earthquake loads are applicable in accordance with the 
New York City
Building Code
, 
water heater supports shall be designed and installed for the seismic forces in accordance with the 
New York City 
Building Code
.
502.
5 Clearances for maintenance and replacement. 
Appliances shall be provided with access
for inspection, ser-
vice, repair and replacement without disabling the function of a fire
-
resistance
-
rated assembly or removing permanent 
construction, other appliances o
r any other piping or ducts not connected to the appliance being inspected, serviced, 
repaired or replaced. A level working space not less than 30 inches in length and 30 inches in width (762 mm by 762 
mm) shall be provided in front of the control side to 
service an appliance.
SECTION 
PC 
503
CONNECTIONS
503.1 Cold water line valve. 
The cold water branch
line from the main water supply line to each hot water storage 
tank or water heater shall be provided with a valve, located near the equipment and serving o
nly the hot water storage 
tank or water heater. The valve shall not interfere or cause a disruption of the cold water supply to the remainder of 
the cold water system. The valve shall be provided with access
on the same floor level as the water heater serv
ed.
503.2 Water circulation. 
The method of connecting a circulating water heater to the tank shall provide proper circu-
lation of water through the water heater. The pipe or tubes required for the installation of appliances that will draw 
from the water hea
ter or storage tank shall comply with the provisions of this code for material and installation.
SECTION 
PC 
504
SAFETY DEVICES
504.1 Antisiphon devices. 
An approved
means, such as a cold water “dip” tube with a hole at the top or a vacuum 
relief valve installed in the cold water supply line above the top of the heater or tank, shall be provided to prevent 
siphoning of any storage water heater or tank.
504.2 Vacuum rel
ief valve. 
Bottom fed water heaters and bottom fed tanks connected to water heaters shall have a 
vacuum relief valve installed. The vacuum relief valve shall comply with ANSI Z21.22.
WATER HEATERS
504.3 Shutdown. 
A means for disconnecting an electric hot water supply system from its energy supply shall be 
provided in accordance with 
the 
New York City Electrical Code
. A separate valve shall be provided to shut off the 
energy fuel supply to all other types of hot wat
er supply systems in accordance with the 
New York City Fuel Gas Code
and 
New York City Mechanical Code
.
504.4 Relief valve.
Storage
water heaters operating above atmospheric pressure shall be provided with an approved, 
self
-
closing (levered) pressure relie
f valve and temperature relief valve or combination thereof. The relief valve shall 
conform to ANSI Z21.22. The relief valve shall not be used as a means of controlling thermal expansion.
504.4.1 Installation. 
Such valves shall be installed in the shell of
the storage water heater tank. Temperature relief 
valves shall be so located in the tank as to be actuated by the water in the top 6 inches (152 mm) of the tank served. 
For installations with separate storage tanks, the approved, self
-
closing (levered) pr
essure relief valve and temper-
ature relief valve or combination thereof conforming to ANSI Z21.22, shall be installed on both the 
storage
water 
heater and
storage tank. There shall not be a check valve or shutoff valve between a relief valve and the heater
or 
tank served.
504.5 Relief valve approval. 
Temperature and pressure relief valves, or combinations thereof, and energy cutoff 
devices shall bear the label of an approved
agency and shall have a temperature setting of not more than 210°F (99°C) 
and a pre
ssure setting not exceeding the tank or water heater manufacturer’s rated working pressure. The relieving 
capacity of each pressure relief valve and each temperature relief valve shall equal or exceed the heat input to the 
water heater or storage tank.
504
.6 Requirements for discharge piping. 
The discharge piping serving a pressure relief valve, temperature relief 
valve or combination thereof shall:
1.
Not be directly connected to the drainage system.
2.
Discharge through an air gap
located in the same ro
om as the water heater.
3.
Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
4.
Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
5.
Discharge in a manner that does not cause personal injury or structural damage.
6.
Discharge to a termination point that is readily observable by the building occupants.
7.
Not be trapped.
8.
Be installed so as to flow by gravity.
9.
Terminate not more
than 6 inches (152 mm) above and not less than two times the discharge pipe diameter 
above the floor or flood level rim of the waste receptor.
10.
Not have a threaded connection at the end of such piping.
11.
Not have valves or tee fittings.
12.
Be constr
ucted of those materials listed in Section 605.4 or materials tested, rated and approved
for such use 
in accordance with ASME A112.4.1.
504.7 Required pan. 
Where a storage tank
-
type water heater or a hot water storage tank is installed in a location 
where water leakage 
from
the 
tank
will cause damage, the tank shall be installed in a galvanized steel pan having a 
material thickness of not less than 0.0236 inc
h (0.6010 mm) (No. 24 gage), or other pans approved
for such use.
504.7.1 Pan size and drain. 
The pan shall be not less than 1
1
/
2
inches (38 mm) in depth and shall be of sufficient 
size and shape to receive all dripping or condensate from the tank or water
heater. The pan shall be drained by an 
indirect waste pipe having a diameter of not less than 
3
/
4
inch (19 mm). Piping for safety pan drains shall be of 
those materials listed in Table 605.4.
Exception:
A pan drain shall not be required for a replacement 
water heater where a pan drain was not previously 
installed, provided that a leak detector is installed within the pan.
504.7.2 Pan drain termination. 
The pan drain shall extend full size and terminate over a suitably located indirect 
waste receptor or flo
or drain or extend to the exterior of the building and terminate not less than 6 inches (152 mm) 
and not more than 24 inches (610 mm) above the adjacent ground 
surface at a point that is readily observable by 
the building occupants
. 
WATER HEATERS
504.8 Flow
-
sensing swi
tch.
On copper fin tube, gas
-
fired domestic hot water heaters, a flow switch shall be provided 
to interrupt the gas supply to the heater in the event water flow through the coil is interrupted.
SECTION 
PC 
505
INSULATION
505.1 Unfired vessel insulation. 
Unf
ired hot water storage tanks shall be insulated in accordance with the 
New York 
City Energy Conservation Code
.