Chapter 1 Administration

Chapter 2 Definitions

Chapter 3 General Regulations

Chapter 4 Ventilation Air

Chapter 5 Exhaust Systems

Chapter 6 Duct Systems

Chapter 7 Combustion Air

Chapter 8 Chimneys and Vents

Chapter 9 Installation of Specific Appliances

Chapter 10 Boilers and Pressure Vessels

Chapter 11 Refrigeration

Chapter 12 Hydronics

Chapter 13 Fuel Gas Piping

Chapter 14 Process Piping

Chapter 15 Solar Energy Systems

Chapter 16 Stationary Power Plants

Chapter 17 Referenced Standards

Appendices [PDF]

Appendix A Residential Plan Examiner Review Form for HVAC System Design

Appendix B Procedures to be Followed to Place Gas Equipment in Operation

Appendix C Installation and Testing of Oil (Liquid) Fuel-Fired Equipment

Appendix D Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks

Appendix E Sustainable Practices

Appendix F Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design

Appendix G Example Calculation of Outdoor Air Rate

This chapter addresses requirements for the design, construction, and installation of specific appliances. In addition to the requirements of this chapter, appliances shall comply with the general requirements of Chapter 3.
This chapter is applicable primarily to nonindustrial-type appliances and installations and, unless specifically indicated. does not apply to industrial-type appliances and installations. Listed appliances shall be installed in accordance with their listing and the manufacturer's installation instructions or, as elsewhere specified in this chapter, as applicable to the appliance. Unlisted appliances shall be installed as specified in this part as applicable to the appliances. For additional information concerning particular appliances and accessories, including industrial types, reference can be made to the standards listed in Chapter 17.
Appliances shall not be installed so its combustion, ventilation, and dilution air are obtained from a bedroom or bathroom unless the bedroom or bathroom has the required volume in accordance with Section 701.4. [NFPA 54:10.1.2]

[OSHPD 1, 2, & 4] Warm air furnaces shall not be installed under openable windows on exterior walls.
Where additional or replacement equipment or appliances are installed or an appliance is converted to gas from another fuel, the location in which the equipment or appliance is to be operated shall be checked to verify the following:
  1. Air for combustion and ventilation is provided where required. in accordance with the provisions of Section 701.0. Where existing facilities are not adequate, they shall be upgraded to be in accordance with Section 701.0 specifications. [NFPA 54:9.1.2(1)]
  2. The installation components and appliances shall be installed with clearances to combustible material so their operation will not create a hazard to persons or property. Minimum clearances between combustible walls and the back and sides of various conventional types of appliances and their vent connectors are specified in Table 303.10.1 and Table 802.7.3.4. [NFPA 54:9.2.2] It shall be determined that the installation and operation of the additional or replacement appliances do not render the remaining appliances unsafe for continued operation.
  3. The venting system is constructed and sized in accordance with the provisions of Section 802.0. Where the existing venting system is not adequate, it shall be upgraded in accordance with Section 802.0. [NFPA 54:9.1.2(3)]
The appliance shall be connected to the fuel gas for which it was designed. No attempt shall be made to convert the appliance from the gas specified on the rating plate for use with a different gas without consulting the manufacturer's installation instructions, the serving gas supplier, or the appliance manufacturer for complete instructions. [NFPA 54:9.1.3]
The fuel input rate to the appliance shall not be increased or decreased in violation of the approved rating at the altitude where it is being used.
Appliances and equipment shall be furnished either with load-distributing bases or with an approved number of supports to prevent damage to either the building structure or the appliance and the equipment. [NFPA 54:9.1.8.1]
At the locations selected for installation of appliances and equipment, the dynamic and static load-carrying capacities of the building structure shall be checked to determine whether they are capable to carry the additional loads. Appliances and equipment shall be supported and shall be connected to the piping so as not to exert undue stress on the connections. [NFPA 54:9.1.8.2]
Appliances shall not be installed in areas where the open use, handling, or dispensing of flammable liquids occurs, unless the design, operation, or installation reduces the potential of ignition of the flammable vapors. Appliances installed in accordance with Section 305.1, Section 905.8, and Section 905.9 shall be considered to be in accordance with the intent of this provision. [NFPA 54:9.1.9]
Unless otherwise specified, solid-fuel burning appliances shall be installed in accordance with NFPA 211 and the manufacturer's installation instructions.
A combination of appliances, equipment, attachments, or devices used together in a manner shall be in accordance with the standards that apply to the individual appliance and equipment. [NFPA 54:9.1.21]
Non-direct-vent appliances installed in beauty shops, barber shops, or other facilities where chemicals that generate corrosive or flammable products such as aerosol sprays are routinely used shall be located in a mechanical equipment room separate or partitioned off from other areas with provisions for combustion and dilution air from outdoors. Direct-vent appliances in such facilities shall be installed in accordance with the appliance manufacturer's installation instructions. [NFPA 54:9.1.6.2]
Electric air conditioning systems designed for permanent installation shall comply with UL 1995 or UL 60335-2-40.
Gas-fired air conditioners shall comply with Section 903.2.1 through Section 903.2.7.
Gas piping serving heating appliances shall be permitted to serve cooling appliances where heating and cooling appliances are not capable of being operated simultaneously. [NFPA 54:10.2.1] (See Section 1308.4)
To protect against the effects of normal vibration in service, gas engines shall not be rigidly connected to the gas supply piping. [NFPA 54:10.2.2]
The installation of air-conditioning appliances shall comply with the following requirements:
  1. Listed air-conditioning appliances shall be installed with clearances in accordance with the terms oftheir listing and the manufacturer's installation instructions.
  2. Unlisted air-conditioning appliances shall be installed with clearances from combustible material of not less than 18 inches (457 mm) above the appliance and at the sides, front, rear and in accordance with the manufacturer's installation instructions. [NFPA 54:10.2.3(2)]
  3. Listed and unlisted air-conditioning appliances shall be permitted to be installed with reduced clearances to combustible material, provided the combustible material or appliance is protected as described in Table 303.10.1 and such reduction is allowed by the manufacturer's installation instructions. [NFPA 54:10.2.3(3)]
  4. Where the furnace plenum is adjacent to plaster on metal lath or noncombustible material attached to combustible material, the clearance shall be measured to the surface of the plaster or other noncombustible finish where the clearance specified is not more than 2 inches (51 mm). [NFPA 54:10.2.3(4)]
  5. Listed air-conditioning appliances shall have the clearance from supply ducts, within 3 feet (914 mm) of the furnace plenum, be not less than that specified from the furnace plenum. No clearance is necessary beyond this distance. [NFPA 54:10.2.3(5)]
Air-conditioning appliances shall be installed in accordance with the manufacturer's installation instructions. Unless the appliance is listed for installation on a combustible surface, such as a floor or roof, or unless the surface is protected in an approved manner, it shall be installed on a surface of noncombustible construction with noncombustible material and surface finish and with no combustible material against the underside thereof. [NFPA 54:10.2.4]
A furnace plenum supplied as a part of the air-conditioning appliance shall be installed in accordance with the manufacturer's installation instructions. Where a furnace plenum is not supplied with the appliance, fabrication and installation instructions provided by the manufacturer shall be followed. The method of connecting supply and return ducts shall facilitate circulation of air. Where the air conditioner is installed within a c1oset, the air circulated by the appliance shall be handled by ducts that are scaled to the casing of the appliance and that separate the circulating air from the combustion and ventilation air. [NFPA 54:10.2.5]
The installation of refrigeration coils shall be in accordance with Section 904.8 and Section 904.9. [NFPA 54:10.2.6]
Means for interrupting the electrical supply to the air-conditioning appliance and to its associated cooling tower (where supplied and installed in a location remote from the air conditioner) shall be provided within sight of and not over 50 feet (15240 mm) from the air conditioner and cooling tower. [NFPA 54:10.2.7]
Central heating furnace and low-pressure boiler installations in bedrooms or bathrooms shall comply with one of the following:
  1. Central heating furnaces and low-pressure boilers shall be permitted to be installed in a closet located in the bedroom or bathroom, provided the closet is equipped with a listed, gasketed door assembly, and a listed self-closing device. The self-closing door assembly shall comply with the requirements of Section 904.1.1. The door assembly shall be installed with a threshold and bottom door seal and shall comply with the requirements of Section 904.1.2. Combustion air for such installations shall be obtained from the outdoors. The closet shall be for the exclusive use of the central heating furnace or low-pressure boiler.
  2. Central heating furnaces and low-pressure boilers shall be of the direct-vent type.
Self-closing doors shall swing easily and freely, and shall be equipped with a self-closing device to cause the door to close and latch each time it is opened. The closing mechanism shall not have a hold-open feature.
Gasketing on gaskets doors or frames shall be furnished in accordance with the published listings of the door, frame, or gasketing material manufacturer.

Exception: Where acceptable to the Authority Having Jurisdiction, gasketing of noncombustible or limited-combustible material shall be permitted to be applied to the frame, provided closing and latching of the door are not inhibited.
Central heating boilers and furnaces shall be provided with clearances in accordance with the following:
  1. Listed central heating furnaces and low-pressure boilers shall be installed with clearances in accordance with the tenns of their listings and the manufacturer's installation instructions.
  2. Unlisted central-heating furnaces and low pressure boilers shall be installed with clearances from combustible material not less than those specified in Table 904.2. [NFPA 54:10.3.2.2]
  3. Listed and unlisted central heating furnaces and low-pressure boilers shall be permitted to be installed with reduced clearances to combustible material provided that the combustible material or appliance is protected in accordance with Table 303.10.1 and Figure 303.10.1(1) through Figure 303.10.1(3), and such reduction is allowed by the manufacturer's installation instructions. [NFPA 54:10.3.2.3]
  4. Front clearance shall be sufficient for servicing the burner and the furnace or boiler. [NFPA 54:10.3.2.4]
  5. Where the furnace plenum is adjacent to plaster on metal lath or noncombustible material attached to combustible material, the clearance shall be measured to the surface of the plaster or other noncombustible finish where the clearance specified is 2 inches (51 mm) or less. [NFPA 54:10.3.2.5]
  6. The clearance to these appliances shall not interfere with combustion air, draft hood clearance and relief, and accessibility for servicing. [NFPA 54:10.3.2.6]
  7. Supply air ducts connecting to listed central heating furnaces shall have the same minimum clearance to combustibles as required for the furnace supply plenum for a distance of not less than 3 feet (914 mm) from the supply plenum. Clearance is not required beyond the 3 feet (914 mm) distance. [NFPA 54:10.3.2.7]
  8. Supply air ducts connecting to unlisted central heating furnaces equipped with temperature limit controls with a maximum setting of 250°F (121°C) shall have a minimum clearance to combustibles of 6 inches (152 mm) for a distance of not less than 6 feet (1829 mm) from the furnace supply plenum. Clearance shall not be required beyond the 6 feet (1829 mm) distance. [NFPA 54:10.3.2.8]
  9. Central heating furnaces other than those listed in Section 904.2(7) or Section 904.2(8) shall have clearances from the supply ducts of not less than 18 inches (457 mm) from the furnace plenum for the first 3 feet (914 mm), then 6 inches (152 mm) for the next 3 feet (914 mm) and 1 inch (25.4 mm) beyond 6 feet (1829 mm). [NFPA 54:10.3.2.9]

TABLE 904.2
CLEARANCES TO COMBUSTIBLE MATERIAL FOR UNLISTED FURNACES, BOILERS, AND AIR CONDITIONERS*
[NFPA 54: TABLE 10.3.2.2]
MINIMUM CLEARANCE (inches)
APPLIANCE ABOVE AND SIDES
OF FURNACE
PLENUM
TOP OF
BOILER
JACKET
SIDES AND
REAR
FRONT DRAFT HOOD AND
BAROMETRIC DRAFT
REGULATOR
SINGLE-WALL VENT
CONNECTOR
Automatically fired, forced air or gravity system,
equipped with temperature limit control that is
not capable of being set to exceed 250°F.
6 - 6 18 6 18
Automatically fired heating boilers-
system boilers operating not exceeding
15 pounds-force per square inch (psi)
and hot water boilers operating at
250°F or less.
6 6 6 18 18 18
Central heating boilers and furnaces,
other than in 1 or 2.
18 18 18 18 18 18
Air-conditioning appliance. 18 18 18 18 18 18
For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8, 1 pound-force per square inch = 6.8947 kPa
*  See Section 903.2.3 for additional requirements for air-conditioning appliances and Section 904.1 for additional requirements for central heating boilers and furnaces.
A central-heating boiler or furnace shall be installed in accordance with the manufacturer's installation instructions. It shall be installed on a floor of noncombustible construction with noncombustible flooring, and surface finish and with no combustible material against the underside thereof, or on fire-resistive slabs or arches having no combustible material against the underside thereof.

Exceptions:
  1. Appliances listed for installation on a combustible floor.
  2. Installation on a floor protected in an approved manner. [NFPA 54:10.3.3]
Furnaces installed in an under-floor area of the building shall be in accordance with the Section 904.3.1.1 through Section 904.3.1.3.
Where a furnace is supported by the ground, it shall be installed on a concrete slab not less than 3 inches (76 mm) above the adjoining ground level.
Where a furnace is supported from above, a clearance of not less than 6 inches (152 mm) shall be provided from finished grade.
Where excavation is necessary to install a furnace, it shall extend to a depth of 6 inches (152 mm) below and 12 inches (305 mm) on all sides of the furnace, except on the service side, which shall have 30 inches (762 mm). Where the depth of the excavation for either the furnace or passageway exceeds 12 inches (305 mm), walls shall be lined with concrete or masonry 4 inches (102 mm) above the adjoining ground level.
Steam and hot water boilers, respectively, shall be provided with approved automatic limiting devices for shutting down the burner(s) to prevent boiler steam pressure or boiler water temperature from exceeding the maximum allowable working pressure or temperature. Safety limit controls shall not be used as operating controls. [NFPA 54:10.3.4]
Water boilers and steam boilers shall be provided with an automatic means to shut off the fuel supply to the burner(s) where the boiler water level drops to the lowest safe water line. In lieu of the low-water cutoff, water tube or coil-type boilers that require forced circulation to prevent overheating and failure shall have an approved flow sensing device arranged to shut down the boiler where the flow rate is not capable of protecting the boiler against overheating. [NFPA 54:10.3.5]
Steam and hot water boilers shall be equipped, respectively, with listed or approved steam safety or pressure-relief valves of discharge capacity and shall comply with ASME requirements. A shutoff valve shall not be placed between the relief valve and the boiler or on discharge pipes between such valves and thc atmosphere. [NFPA 54:10.3.6]
Relief valves shall be piped to discharge near the floor. [NFPA 54:10.3.6.1]
The entire discharge piping shall be not less than the same size as the relief valve discharge piping. [NFPA 54:10.3.6.2]
Discharge piping shall not contain a threaded end connection at its termination point. [NFPA 54:10.3.6.3]
Furnace plenums and air ducts shall be installed in accordance with the following:
  1. Furnace plenums and air ducts shall be installed in accordance with NFPA 90A.
  2. A furnace plenum supplied as a part of a furnace shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:10.3.7.2]
  3. Where a furnace plenum is not supplied with the furnace, fabrication, and installation shall be in accordance with the manufacturer's installation instructions. The method of connecting supply and return ducts shall facilitate circulation of air. [NFPA 54:10.3.7.3]
  4. Where a furnace is installed so supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall be handled by a duct(s) sealed to the furnace casing and terminating outside the space containing the furnace. [NFPA 54:10.3.7.4]
The installation of refrigeration coils shall comply with the following requirements:
  1. A refrigeration coil shall not be installed in conjunction with a forced-air furnace where circulation of cooled air is provided by the furnace blower, unless the blower has the capacity to overcome the external static pressure resistance imposed by the duct system and refrigeration coil at the air flow rate for heating or cooling, whichever is greater.
  2. Furnaces shall not be located upstream from refrigeration coils, unless the refrigeration coil is designed or equipped so as not to develop excessive temperature or pressure.
  3. Refrigeration coils shall be installed in parallel with or on the downstream side of central furnaces to avoid condensation in the heating element unless the furnace has been specifically listed for downstream installation. With a parallel flow arrangement the dampers or other means used to control flow of air shall be tight to prevent a circulation of cooled air through the furnace.
  4. Means shall be provided for disposal of condensate and to prevent dripping of condensate on the heating element. [NFPA 54:10.3.8]
Cooling coils used with heating boilers shall be installed in accordance with the following:
  1. Boilers, where used in conjunction with refrigeration systems, shall be installed so that the chilled medium is piped in parallel with the heating boiler with valves to prevent the chilled medium from entering the heating boiler. [NFPA 54:10.3.9.1]
  2. Where hot-water-heating boilers are connected to heating coils located in air-handling units where they are capable of being be exposed to refrigerated air circulation, such boiler piping systems shall be equipped with flow control valves or other automatic means to prevent gravity circulation of the boiler water during the cooling cycle. [NFPA 54:10.3.9.2]
Upright furnaces shall be permitted to be installed in an attic, furred, or underfloor space exceeding 5 feet (1524 mm) in height, provided the required listings and furnace and duct clearances are observed. Horizontal furnaces shall be permitted to be installed in an attic, furred, or under-floor space, provided the required listings and furnace and duct clearances are observed.
Factory-built solid-fuel furnaces shall comply with UL 391 and installed in accordance with the manufacturer's installation instructions.
Oil-fired central furnaces shall comply with UL 727 and installed in accordance with the manufacturer's installation instructions.
Commercial or industrial gas heaters shall comply with UL 795 and installed in accordance with the manufacturer's installation instructions.
The installation of duct furnaces shall comply with the following clearance requirements:
  1. Listed duct furnaces shall be installed with clearances of not less than 6 inches (152 mm) between adjacent walls, ceilings, and floors of combustible material and the furnace draft hood. Furnaces listed for installation at lesser clearances shall be installed in accordance with their listings and the manufacturer's installation instructions. In no case shall the clearance be such as to interfere with combustion air and accessibility.
  2. Unlisted duct furnaces shall be installed with clearances to combustible material in accordance with the clearances specified for unlisted furnaces and boilers in Table 904.2. Combustible floors under unlisted duct furnaces shall be protected in an approved manner.
Duct furnaces shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:10.10.2]
The ducts connected to duct furnaces shall have removable access panels on both the upstream and downstream sides of the furnace. [NFPA 54:10.10.3]
The controls, combustion-air inlet, and draft hoods for duct furnaces shall be located outside the ducts. The draft hood shall be located in the same enclosure from which combustion air is taken. [NFPA 54:10.10.4]
Where a duct furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air shall also be handled by a duct(s) sealed to the furnace casing and terminating outside the space containing the furnace. The duct furnace shall be installed on the positive-pressure side of the circulating air blower. [NFPA 54:10.10.5]
Duct furnaces used with refrigeration systems shall be installed in accordance with the following:
  1. A duct furnace shall not be installed in conjunction with a refrigeration coil where circulation of cooled air is provided by the blower.

    Exception: Where the blower has capacity to overcome the external static resistance imposed by the duct system, furnace, and the cooling coil and the air throughput necessary for heating or cooling, whichever is greater. [NFPA 54:10.10.6.1]
  2. Duct furnaces used in conjunction with cooling appliances shall be installed in parallel with or on the upstream side of cooling coils to avoid condensation within heating elements. With a parallel flow arrangement, the dampers or other means used to control the flow of air shall be tight to prevent a circulation of cooled air through the unit.

    Exception: Where the duct furnace has been specifically listed for downstream installation. [NFPA 54:10.10.6.2]
  3. Where duct furnaces are to be located upstream from cooling units, the cooling unit shall be so designed or equipped as to not develop excessive temperatures or pressures. [NFPA 54:10.10.6.3]
  4. Where a duct furnace is installed downstream of an evaporative cooler or air washer, the heat exchanger shall be constructed of corrosion-resistant materials. Stainless steel, ceramic-coated steel, and an aluminum-coated steel in which the bond between the steel and the aluminum is an iron-aluminum alloy are considered to be corrosion resistant. Air washers operating with chilled water that deliver air below the dew point of the ambient air at the duct furnace are considered as refrigeration systems. [NFPA 54:10.10.6.4]
Duct furnaces installed in garages for more than three motor vehicles or in aircraft hangars shall be of a listed type and shall be installed in accordance with Section 905.8 and Section 905.9. [NFPA 54:10.10.7]
Appliances installed in enclosed, basement, and underground parking structures shall be installed in accordance with NFPA 88A. [NFPA 54:9.1.11.1]
Appliances installed in repair garages shall be installed in a detached building or room, separated from repair areas by walls, partitions, floors, or floor-ceiling assemblies that are constructed so as to prohibit the transmission of vapors and having a fire resistance rating of not less than 1 hour, and that have no openings in the wall separating the repair area within 8 feet (2438 mm) of the floor. Wall penetrations shall be firestopped. Air for combustion purposes shall be obtained from outside the building. The heating room shall not be used for the storage of combustible materials.

Exceptions:
  1. Overhead heaters where installed not less than 8 feet (2438 mm) above the floor shall be permitted.
  2. Heating appliances for vehicle repair areas where there is no dispensing or transferring of Class I or Class II flammable or combustible liquids or liquefied petroleum gas shall be installed in accordance with NFPA 30A. [NFPA 54:9.1.11.2]
Heaters in aircraft hangars shall be installed in accordance with NFPA 409. [NFPA 54:9.1.12]
Electric duct heaters installed within an air duct shall be listed for such use and designed for the maximum air temperature. The duct heater and fan shall be interlocked such that the electric duct heater operates when the fan is operating.
Duct heaters shall be installed in accordance with the manufacturer's installation instructions, and shall not create a hazard to persons or property. Where installed 4 feet (1219 mm) or less from a heat pump or air conditioner, the duct heater shall be listed for such installation.
A working space clearance shall be maintained to permit replacement of controls and heating elements and for adjusting and cleaning of controls. The working space for energized equipment shall comply with NFPA 70.
The installation of floor furnaces shall comply with the following requirements:
  1. Listed floor furnaces shall be installed in accordance with their listing and the manufacturer's installation instructions.
  2. Unlisted floor furnaces shall not be installed in combustible floors.
  3. Thennostats controlling floor furnaces shall not be located in a room or space that is capable of being separated from the room or space in which the register of the floor furnace is located.
Floor furnaces shall be provided with temperature limit controls in accordance with the following requirements:
  1. Listed automatically operated floor furnaces shall be equipped with temperature limit controls. [NFPA 54:10.11.2.1]
  2. Unlisted automatically operated floor furnaces shall be equipped with a temperature limit control arranged to shut off the flow of gas to the burner in the event the temperature at the warm air outlet register exceeds 350°F (177°C) above room temperature. [NFPA 54:10.11.2.2]
Combustion and circulating air shall be provided in accordance with Section 701.0. [NFPA 54:10.11.3]
The following provisions apply to furnaces that serve one story:
  1. Floor furnaces shall not be installed in the floor of a doorway, stairway landing, aisle, or passageway of an enclosure, public or private, or in an exitway from such room or space.
  2. The register of a floor furnace with a horizontal warm air outlet shall not be placed closer than 6 inches (152 mm) from the nearest wall. A distance of not less than 18 inches (457 mm) from two adjoining sides of the floor furnace register to walls shall be provided to eliminate the necessity of occupants walking over the warm air discharge. The remaining sides shall be not less than 6 inches (152 mm) from a wall. Wall-register models shall not be placed closer than 6 inches (152 mm) to a corner.
  3. The furnace shall be placed so that a door, drapery, or similar object is not closer than 12 inches (305 mm) to a portion of the register of the furnace. [NFPA 54:10.11.4]
The space provided for the furnace shall be framed with doubled joists and with headers not lighter than the joists. [NFPA 54:10.11.5]
Means shall be provided to support the furnace where the floor register is removed. [NFPA 54:10.11.6]
The lowest portion of the floor furnace shall have not less than a 6 inch (152 mm) clearance from the general ground level. A reduced clearance to not less than 2 inches (51mm) is permitted, provided the lower 6 inches (152 mm) portion of the floor furnace is sealed by the manufacturer to prevent entrance of water. Where these clearances are not present, the ground below and to the sides shall be excavated to form a "basin-like" pit under the furnace so that the required clearance is provided beneath the lowest portion of the furnace. A 12 inch (305 mm) clearance shall be provided on the sides except the control side, that which has an 18 inch (457 mm) clearance. [NFPA 54:10.11.7]
The space in which a floor furnace is installed shall be accessible by an opening in the foundation not less than 24 inches by 18 inches (610 mm by 457 mm) or by a trap door not less than 24 inches by 24 inches (610 mm by 610 mm) in a cross-section thereof, and a passageway not less than 24 inches by 18 inches (610 mm by 457 mm) in a cross-section thereof. [NFPA 54:10.11.8]
Where the excavation exceeds 12 inches (305 mm) in depth or water seepage is capable of collecting, a watertight copper pan, concrete pit, or other approved material shall be used, unless approved drainage is provided or the appliance is scaled by the manufacturer to meet this condition. A copper pan shall be made of not less than 16 ounces per square foot (oz/ft2) (4.9 kg/m2) sheet copper. The pan shall be anchored in place so as to prevent floating, and the walls shall extend not less than 4 inches (102 mm) above the ground level with not less than 6 inches (152 mm) clearance on all sides, except the control side, which shall have not less than 18 inches (457mm) clearance. [NFPA 54:10.11.9]
Floor furnaces shall be protected, where necessary, against severe wind conditions. [NFPA 54:10.11.10]
Listed floor furnaces shall be permitted to be installed in an upper floor, provided the furnace assembly projects below into a utility room, closet, garage, or similar nonhabitable space. In such installations, the floor furnace shall be enclosed completely (entirely separated from the nonhabitable space) with means for air intake to meet the provisions of Section 701.0, with access for servicing, the furnace clearances of not less than 6 inches (152 mm) to the sides and bottom, and with the enclosure constructed of portland cement plaster or metal lath or other noncombustible material. [NFPA 54:10.11.11]
Listed floor furnaces installed in the first or ground floors of buildings shall not be required to be enclosed unless the basements of these buildings have been converted to apartments or sleeping quarters, in which case the floor furnace shall be enclosed as specified for upper floor installations and shall project into a nonhabitable space. [NFPA 54:10.11.12]
Oil-fired floor furnaces shall comply with UL 729 and installed in accordance with the manufacturer's installation instructions.
Wall furnaces shall be installed in accordance with the following:
  1. Listed wall furnaces shall be installed in accordance with their listings and the manufacturer's installation instructions. Wall furnaces installed in or attached to combustible material shall be listed for such installation.
  2. Unlisted wall furnaces shall not be installed in or attached to combustible material. [NFPA 54:10.27.1.2]
  3. Vented wall furnaces connected to a Type B-W gas vent system listed for a single story shall be installed in single-story buildings or the top story of multistory buildings. Vented wall furnaces connected to a Type B-W gas vent system listed for installation in multistory buildings shall be permitted to be installed in single-story or multistory buildings. Type B-W gas vents shall be attached directly to a solid header plate that serves as a firestop at that point and that shall be permitted to be an integral part of the vented wall furnace, as illustrated in Figure 907.1. The stud space in which the vented wall furnace is installed shall be ventilated at the first ceiling level by installation of the ceiling plate spacers furnished with the gas vent. Firestop spacers shall be installed at each subsequent ceiling or floor level penetrated by the vent. [NFPA 54:10.27.1.3]
  4. Direct-vent wall furnaces shall be installed with the vent-air intake terminal in the outdoors. The thickness of the walls on which the furnace is mounted shall be within the range of wall thickness marked on the furnace and covered in the manufacturer's installation instructions. [NFPA 54:10.27.1.4]
  5. Panels, grilles, and access doors that are required to be removed for normal servicing operations shall not be attached to the building. For additional information on the venting of wall furnaces, see Section 802.0 in this code. [NFPA 54:10.27.1.5]

FIGURE 907.1
INSTAllATiON OFTYPE B-W GAS VENTS FOR
VENTED WALL FURNACES
[NFPA 54: FIGURE 10.27.1.3]
Wall furnaces shall be located so as not to cause a hazard to walls, floors, curtains, furniture, or doors. Wall furnaces installed between bathrooms and adjoining rooms shall not circulate air from bathrooms to other parts of the building. [NFPA 54:10.27.2]
Combustion and circulating air shall be provided in accordance with Section 701.0. [NFPA 54:10.27.3]
Oil-fired wall furnaces shall comply with UL 730 and installed in accordance with the manufacturer's installation instructions.
Commercial electric clothes dryers shall comply with UL 1240 and installed in accordance with the manufacturer's installation instructions. Residential and coin-operated electric clothes dryers shall comply with UL 2158 and installed in accordance with the manufacturer's installation instructions.
Gas-fired clothes dryers shall comply with Section 908.2.1 through Section 908.2.3.
The installation of clothes dryers shall comply with the following requirements:
  1. Listed Type 1 clothes dryers shall be installed with a clearance of not less than 6 inches (152 mm) from adjacent combustible material. Clothes dryers listed for installation at reduced clearances shall be installed in accordance with their listing and the manufacturer's installation instructions. Type 1 clothes dryers installed in closets shall be listed for such installation.
  2. Listed Type 2 clothes dryers shall be installed with clearances of not less than that shown on the marking plate and in the manufacturer's instructions. Type 2 clothes dryers designed and marked, "For use only in noncombustible locations," shall not be installed elsewhere.
  3. Unlisted clothes dryers shall be installed with clearances to combustible material of not less than 18 inches (457mm). Combustible floors under unlisted clothes dryers shall be protected in an approved manner.
Type 1 and Type 2 clothes dryers shall be exhausted to the outside air in accordance with Section 504.4.
Clothes dryers installed for multiple-family or public use shall be equipped with approved safety shutoff devices and shall be installed as specified for a Type 2 clothes dryer in accordance with Section 504.4.3.1. [NFPA 54:10.4.6]
Installation of conversion burners shall comply with CSA Z21.8. [NFPA 54:10.5]
Oil burners shall comply with UL 296 and installed in accordance with the manufacturer's installation instructions.
Commercial gas burners shall comply with UL 295 and installed in accordance with the manufacturer's installation instructions.
Decorative appliances for installation in vented fireplaces shall not be installed in bathrooms or bedrooms unless the appliance is listed and the bedroom or bathroom has the required volume in accordance with Section 701.4. [NFPA 54:10.6.1] [OSHPD 1, 2 & 4] vented decorative appliance shall not be located in any hospital, skilled nursing facility, intermediate care facility, or correctional treatment center.
A decorative appliance for installation in a vented fireplace shall be installed in a vented fireplace having a working chimney flue and constructed of noncombustible materials. These appliances shall not be thermostatically controlled [NFPA 54:10.6.2]:
  1. A listed decorative appliance for installation in a vented fireplace shall be installed in accordance with its listing and the manufacturer's installation instructions.
  2. A decorative appliance for installation in a vented fireplace, where installed in a manufactured home, shall be listed for installation in manufactured homes. [NFPA 54:10.6.2.2]
  3. An unlisted decorative appliance for installation in a vented fireplace shall be installed in a fireplace having a permanent free opening, based on appliance input rating and chimney height, equal to or greater than that specified in Table 911.2. [NFPA 54:10.6.2.3]

TABLE 911.2 FREE OPENING AREA OF CHIMNEY DAMPER FOR VENTING FLUE GASES FROM UNLISTED DECORATIVE
APPLIANCES FOR INSTALLATION IN VENTED FIREPLACES
[NFPA 54: TABLE 10.6.2.3]
CHIMNEY HEIGHT
(feet)
MINIMUM PERMANENT FREE OPENING (square inches)*
8 13 20 29 39 51 64
APPLIANCE INPUT RATING (Btu/h)
6 7800 14000 23200 34000 46400 62400 80000
8 8400 15200 25200 37000 50400 68000 86000
10 9000 16800 27600 40400 55800 74400 96400
15 9800 18200 30200 44600 62400 84000 108800
20 10600 20200 32600 50400 68400 94000 122200
30 11200 21600 36600 55200 76800 105800 138600
For SI units: 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
*  The first six minimum permanent free openings [8 square inches (0.005 m2) to 51 square inches (0.03 m2)] correspond to the cross-sectional areas of chimneys having diameters of 3 inches (76 mm) through 8 inches (203 mm), respectively. The 64 square inch (0.04 m2) opening corresponds to the cross-sectional area of a standard 8 inch (203 mm) by 8 inch (203 mm) chimney tile.
A fireplace screen shall be installed with a decorative appliance for installation in a vented fireplace. [NFPA 54:10.6.3]
The installation of vented gas fireplaces shall comply with the following requirements:
  1. (HCD 1 & HCD 2) Any newly installed gas fireplace shall be a direct-vent sealed-combustion type.
  2. Listed vented gas fireplaces shall be installed in accordance with their listing and the manufacturer's installation instructions and where installed in or attached to combustible material shall be specifically listed for such installation.
  3. Unlisted vented gas fireplaces shall not be installed in or attached to combustible material. They shall have a clearance at the sides and rear of not less than 18 inches (457 mm). Combustible floors under unlisted vented gas fireplaces shall be protected in an approved manner. Unlisted appliances of other than the direct-vent type shall be equipped with a draft hood and shall be vented in accordance with Section 802.0. Appliances that use metal, asbestos, or ceramic material to direct radiation to the front of the appliance shall have a clearance of 36 inches (914 mm) in front and, where constructed with a double back of metal or ceramic, shall be installed with a clearance of not less than 18 inches (457 mm) at the sides and 12 inches (305 mm) at the rear.
  4. Panels, grilles, and access doors that are required to be removed for normal servicing operations shall not be attached to the building.
  5. Direct-vent gas fireplaces shall be installed with the vent air intake terminal in the outdoors and in accordance with the manufacturer's installation instructions.
Combustion and circulating air shall be provided in accordance with Section 701.0. [NFPA 54:10.7.3]
Factory-built fireplaces shall comply with UL 127 and installed in accordance with the manufacturer's installation instructions.
A gasketed fireplace door shall not be installed on a factory-built fireplace, except where the fireplace system has been tested in accordance with UL 127.
Fireplace stoves shall comply with UL 737 and installed in accordance with the manufacturer's installation instructions.
Heat exchangers, glass doors assemblies, combustion air vents, and termination caps shall comply with UL 907 and installed in accordance with the manufacturer's installation instructions.
Direct gas-fired industrial air heaters of the non-recirculating type shall be listed in accordance with CSA Z83.4. [NFPA 54:10.8.1]
Non-recirculating direct gasfired industrial air heaters shall not be installed in the following conditions:
  1. Non-recirculating direct gas-fired industrial air heaters shall not serve an area containing sleeping quarters. [NFPA 54:10.8.2.1]
  2. Non-recirculating direct gas-fired industrial air heaters shall not recirculate room air. [NFPA 54:10.8.2.2]
Installation of direct gas-fired industrial air heaters shall comply with the following requirements:
  1. Non-recirculating direct gas-fired industrial air heaters shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:10.8.3.1]
  2. Non-recirculating direct gas-fired industrial air heaters shall be installed in industrial or commercial occupancies. [NFPA 54:10.8.3.2]
  3. Non-recirculating direct gas-fired industrial air heaters shall be permitted to provide fresh air ventilation. [NFPA 54:10.8.3.3]
  4. Non-recirculating direct gas-fired industrial air heaters shall be provided with an access for removal of burners; replacement of motors, controls, filters, and other working parts; and for adjustment and lubrication of parts requiring maintenance. [NFPA 54:10.8.3.4]
Non-recirculating direct gas-fired industrial air heaters shall be installed with a clearance from combustible materials of not less than that shown on the rating plate and the manufacturer's installation instructions. [NFPA 54:10.8.4]
Air to the non-recirculating direct gas-fired industrial air heater shall be ducted directly from outdoors. Where outside-air dampers or closing louvers are used, they shall be verified to be in the open position prior to main burner operation. [NFPA 54:10.8.5]
Non-recirculating direct gas-fired industrial air heaters with valve train components equipped with atmospheric vents, gas reliefs, or bleeds shall have their vent lines, gas reliefs, or bleeds lead to a safe point outdoors. Means shall be employed on these lines to prevent water from entering and to prevent blockage from insects and foreign matter. An atmospheric vent line shall not be required to be provided on a valve train component equipped with a listed vent limiter. [NFPA 54:10.8.6]
The design of the installation shall include approved provisions to permit the non-recirculating direct gas-fired industrial air heater to operate at its rated airflow without overpressurizing the space served by the heater by taking into account the structure's designed infiltration rate, properly designed relief openings, or an interlocked powered exhaust system, or a combination of these methods:
  1. The structure's designed infiltration rate and the size of relief opening(s) shall be determined by approved engineering methods.
  2. Louver or counterbalanced gravity damper relief openings shall be permitted. Where motorized dampers or closeable louvers are used, they shall be proved to be in their open position prior to main burner operation. [NFPA 54:10.8.7]
Inlet ducting, where used, shall be purged with not less than four air changes prior to an ignition attempt. [NFPA 54:10.8.8]
Direct gas-fired industrial air heaters of the recirculating type shall be listed in accordance with CSA Z83.18. [NFPA 54:10.9.1]
Recirculating direct gas-fired industrial air heaters shall not be installed in the following conditions:
  1. Recirculating direct gas-fired industrial air heaters shall not serve an area containing sleeping quarters. [NFPA 54:10.9.2.1]
  2. Recirculating direct gas-fired industrial air heaters shall not recirculate room air in buildings that contain flammable solids, liquids, or gases, explosive materials, or substances that are capable of becoming toxic where exposed to flame or heat. [NFPA 54:10.9.2.2]
Installation of direct gas-fired industrial air heaters shall comply with the following requirements:
  1. Recirculating direct gas-fired industrial air heaters shall be installed in accordance with the manufacturer's installation instructions.
  2. Recirculating direct gas-fired industrial air heaters shall be installed in industrial or commercial occupancies. [NFPA 54:10.9.3]
Recirculating direct gas-fired industrial air heaters shall be installed with a clearance from combustible materials of not less than that shown on the rating plate and the manufacturer's installation instructions. [NFPA 54:10.9.4]
Ventilation air to the recirculating direct gas-fired industrial air heater shall be ducted directly from outdoors. Air to the recirculating direct gas-fired industrial air heater in excess of the minimum ventilation air specified on the heater's rating plate shall be taken from the building, ducted directly from outdoors, or a combination of both. Where outdoor air dampers or closing louvers are used, they shall be verified to be in the open position prior to main burner operation. [NFPA 54:10.9.5]
Recirculating direct gas-fired industrial air heaters with valve train components equipped with atmospheric vents, gas reliefs, or bleeds shall have their vent lines, gas reliefs, or bleeds lead to a safe point outdoors. Means shall be employed on these lines to prevent water from entering and to prevent blockage from insects and foreign matter. An atmospheric vent line shall not be required to be provided on a valve train component equipped with a listed vent limiter. [NFPA 54:10.9.6]
The design of the installation shall include provisions to permit the recirculating direct gas-fired industrial air heater to operate at its rated airflow without overpressurizing the space served by the heater by taking into account the structure's designed infiltration rate, properly designed relief openings or an interlocked powered exhaust system, or a combination of these methods [NFPA 54:10.9.7]:
  1. The structure's designed infiltration rate and the size of relief opening(s) shall be determined by approved engineering methods. [NFPA 54:10.9.7.1]
  2. Louver or counterbalanced gravity damper relief openings shall be permitted. Where motorized or closeable louvers are used, they shall be proved to be in their open position prior to main burner operation. [NFPA 54:1O.9.7.2]
Inlet ducting, where used, shall be purged with not less than four air changes prior to an ignition attempt. [NFPA 54:10.9.8]
Electric room heaters shall comply with UL 2021.
Gas-fired room heaters shall comply with Section 916.2.1 through Section 916.2.4.
Unless specifically permitted by the Authority Having Jurisdiction, unvented room heaters shall not be installed as primary heat sources. Unvented room heaters shall not be permitted in spaces that do not have the required volume of indoor air as defined in Section 701.4.

[HCD 1 & HCD 2] Unvented fuel-burning room heaters shall not be installed, used, maintained, or permitted to exist in a Group R Occupancy.
Unvented room heaters shall not be installed in bathrooms or bedrooms.

Exceptions:
  1. Where approved by the Authority Having Jurisdiction, one listed wall-mounted unvented room heater equipped with an oxygen depletion safety shutoff system shall be permitted to be installed in a bathroom provided that the input rating does not exceed 6000 Btu/h (1.76 kW) and combustion and ventilation air is provided in accordance with Section 902.2.
  2. Where approved by the Authority Having Jurisdiction, one listed wall-mounted unvented room heater equipped with an oxygen depletion safety shutoff system shall be permitted to be installed in a bedroom provided that the input rating does not exceed 10000 Btu/h (3 kW) and combustion and ventilation air is provided in accordance with Section 902.2. [NFPA 54:10.23.1]
  3. Portable oil fired unvented heating appliances used as supplemental heating in storage occupancies, utility occupancies, and in accordance with the fire code.
[HCD 1 & HCD 2] Unvented fuel-burning room heaters shall not be installed, used, maintained, or permitted to exist in a Group R Occupancy.
Room heaters shall not be installed in the following occupancies:
  1. Residential board and care
  2. Health care [NFPA 54:10.23.3]
A room heater shall be placed so as not to cause a hazard to walls, floors, curtains. furniture, doors where open, and to the free movements of persons within the room. Heaters designed and marked, "For use in noncombustible fireplace only," shall not be installed elsewhere. Listed room heaters shall be installed in accordance with their listings and the manufacturer's installation instructions. In no case shall the clearances be such as to interfere with combustion air and accessibility. Unlisted room heaters shall be installed with clearances from combustible material not less than the following:
  1. Circulating type room heaters having an outer jacket surrounding the combustion chamber, arranged with openings at top and bottom so that air circulates between the inner and outer jacket, and without openings in the outer jacket to permit direct radiation, shall have clearance at sides and rear of not less than 12 inches (305 mm).
  2. Radiating type room heaters other than those of the circulating type described in Section 916.2.3(1) shall have clearance at sides and rear of not less than 18 inches (457 mm), except that heaters that make use of metal, asbestos, or ceramic material to direct radiation to the front of the heater shall have a clearance of 36 inches (914 mm) in front and, where constructed with a double back of metal or ceramic, shall be permitted to be installed with a clearance of 18 inches (457 mm) at sides and 12 inches (305 mm) at rear. Combustible floors under unlisted room heaters shall be protected in an approved manner.
Wall-type room heaters shall not be installed in or attached to walls of combustible material unless listed for such installation. [NFPA 54:10.23.5]
Solid-fuel type room heaters shall comply with UL 1482.
Suspended-type unit heaters shall be supported with due consideration given to their weight and vibration characteristics. Hangers and brackets shall be of noncombustible material. [NFPA 54:10.26.1]
Suspended-type unit heaters shall comply with the following requirements:
  1. A listed unit heater shall be installed with clearances from combustible material of not less than 18 inches (457 mm) at the sides, 12 inches (305 mm) at the bottom, and 6 inches (152 mm) above the top where the unit heater has an internal draft hood, or 1 inch (25.4 mm) above the top of the sloping side of a vertical draft hood. A unit heater listed for reduced clearances shall be installed in accordance with its listing and the manufacturer's installation instructions.
  2. Unlisted unit heaters shall be installed with clearances to combustible material of not less than 18 inches (457 mm).
  3. Clearances for servicing shall be in accordance with the manufacturer's installation instructions.
Floor-mounted-type unit heaters shall comply with the following requirements:
  1. A listed unit heater shall be installed with clearances from combustible material at the back and one side of not less than 6 inches (152 mm). Where the flue gases are vented horizontally, the 6 inch (152 mm) clearance shall be measured from the draft hood or vent instead of the rear wall of the unit heater. A unit heater listed for reduced clearances shall be installed in accordance with its listing and the manufacturer's installation instructions.
  2. Floor-mounted-type unit heaters installed on combustible floors shall be listed for such installation.
  3. Combustible floors under unlisted floor-mounted unit heaters shall be protected in an approved manner.
  4. Clearances for servicing shall be in accordance with the manufacturer's instructions.
Combustion and circulating air shall be provided in accordance with Section 701.0. [NFPA 54:10.26.3]
A unit heater shall not be attached to a warm air duct system unless listed and marked for such installation. [NFPA 54:10.26.4]
Unit heaters installed in garages for more than three motor vehicles or in aircraft hangars shall be of a listed type and shall be installed in accordance with Section 905.8 and Section 905.9. [NFPA 54:10.26.5]
Oil-fired unit heaters shall comply with UL 731 and installed in accordance with the manufacturer's installation instructions.
Listed floor-mounted food service appliances, such as ranges for hotels and restaurants, deep-fat fryers, unit broilers, kettles, steam cookers, steam generators, and baking and roasting ovens, shall be installed not less than 6 inches (152 mm) from combustible material except that not less than a 2 inch (51 mm) clearance shall be maintained between a draft hood and combustible material. Floor-mounted food service appliances listed for installation at lesser clearances shall be installed in accordance with its listing and the manufacturer's installation instructions. Appliances designed and marked, "For use only in noncombustible locations," shall not be installed elsewhere.
Unlisted floor-mounted food service appliances shall be installed to provide a clearance to combustible material of not less than 18 inches (457 mm) from the sides and rear of the appliance and from the vent connector and not less than 48 inches (1219 mm) above cooking tops and at the front of the appliance.

    Clearances for unlisted appliances installed in partially enclosed areas such as alcoves shall not be reduced. Where clearances for unlisted appliances installed in rooms that are not partially enclosed shall be in accordance with Table 303.10.1. [NFPA 54:10.12.2]
Mounting on combustible floors shall be in accordance with the following:
  1. Listed floor-mounted food service appliances that are listed specifically for installation on floors constructed of combustible material shall be permitted to be installed on combustible floors in accordance with its listing and the manufacturer's installation instructions.
  2. Floor-mounted food service appliances that are not listed for mounting on a combustible floor shall be mounted in accordance with Section 918.4 or be mounted in accordance with one of the following:

    1. Where the appliance is set on legs that provide not less than 18 inches (457 mm) open space under the base of the appliance or where it has no burners and no portion of an oven or broiler within 18 inches (457 mm) of the floor, it shall be permitted to be mounted on a combustible floor without special floor protection, provided there is not less than one sheet metal baffle between the burner and the floor.
    2. Where the appliance is set on legs that provide not less than 8 inches (203 mm) open space under the base of the appliance, it shall be permitted to be mounted on combustible floors, provided the floor under the appliance is protected with not less than 38 of an inch (9.5 mm) insulating millboard covered with sheet metal not less than 0.0195 of an inch (0.4953 mm) thick. The preceding specified floor protection shall extend not less than 6 inches (152 mm) beyond the appliance on all sides.
    3. Where the appliance is set on legs that provide not less than 4 inches (102 mm) under the base of the appliance, it shall be permitted to be mounted on combustible floors, provided the floor under the appliance is protected with hollow masonry not less than 4 inches (102 mm) in thickness covered with sheet metal not less than 0.0195 of an inch (0.4953 mm) thick. Such masonry courses shall be laid with ends unsealed and joints matched in such a way as to provide for free circulation of air through the masonry.
    4. Where the appliance does not have legs not less than 4 inches (102 mm) high, it shall be permitted to be mounted on combustible floors, provided the floor under the appliance is protected by two courses of 4 inch (102 mm) hollow clay tile with courses laid at right angles and with ends unsealed and joints matched in such a way as to provide for free circulation of air through such masonry courses, and covered with steel plate not less than 316 of an inch (4.8 mm) in thickness. [NFPA 54:10.12.3.2]
Listed floor-mounted food service appliances that are designed and marked, "For use only in noncombustible locations," shall be installed on floors of noncombustible construction with noncombustible flooring and surface finish and with no combustible material against the underside thereof, or on noncombustible slabs or arches having no combustible material against the underside thereof. Such construction shall extend not less than 12 inches (305 mm) beyond the appliance on all sides. [NFPA 54:10.12.4]
A portion of combustible material adjacent to a cooking top section of a food service range, even though listed for close-to-wall installation, that is not shielded from the wall by a high shelf, warming closet, and so on, shall be protected as specified in Section 918.2 for a distance of not less than 2 feet (610 mm) above the surface of the cooking top. [NFPA 54:10.12.5]
Floor-mounted appliances with casters shall be listed for such construction and shall be installed in accordance with the manufacturer's installation instructions for limiting the movement of the appliance to prevent strain on the connection. [NFPA 54:10.12.6]
Floor-mounted food service appliances shall be installed level on a firm foundation. [NFPA 54:10.12.7]
Means shall be provided to ventilate the space in which food service appliance is installed to permit combustion of the gas. [NFPA 54:10.12.8]
A vertical distance of not less than 48 inches (1219 mm) shall be provided between the top of food service hot plates and griddles and combustible material. [NFPA 54:10.13.1]
Listed food service counter appliances such as hot plates and griddles, food and dish warmers, and coffee brewers and urns, where installed on combustible surfaces, shall be set on their own bases or legs and shall be installed with a horizontal clearance of not less than 6 inches (152 mm) from combustible material, except that not less than a 2 inches (51 mm) clearance shall be maintained between a draft hood and combustible material. Food service counter appliances listed for installation at lesser clearances shall be installed in accordance with their listing and the manufacturer's installation instructions.
Unlisted food service hot plates and griddles shall be installed with a horizontal clearance from combustible material of not less than 18 inches (457 mm). Unlisted gas food service counter appliances, including coffee brewers and urns, waffle bakers, and hot water immersion sterilizers, shall be installed with a horizontal clearance from combustible material of not less than 12 inches (305 mm). Reduced clearances for gas food service counter appliances shall be in accordance with Table 303.10.1. Unlisted food and dish warmers shall be installed with a horizontal clearance from combustible material of not less than 6 inches (152 mm). [NFPA 54:10.13.3]
Unlisted food service counter appliances shall not be set on combustible material unless they have legs that provide not less than 4 inches (102 mm) of open space below the burners and the combustible surface is protected with insulating millboard not less than 14 of an inch (6.4 mm) thick covered with sheet metal not less than 0.0122 of an inch (0.3099 mm) thick, or with equivalent protection. [NFPA 54:10.13.4]
Hot plates and laundry stoves shall be installed in accordance with the following:
  1. Listed domestic hot plates and laundry stoves installed on combustible surfaces shall be set on their own legs or bases. They shall be installed with horizontal clearances of not less than 6 inches (152 mm) from combustible material. [NFPA 54:10.14.1]
  2. Unlisted domestic hot plates and laundry stoves shall be installed with horizontal clearances to combustible material of not less than 12 inches (305 mm). Combustible surfaces under unlisted domestic hot plates and laundry stoves shall be protected in an approved manner. [NFPA 54:1O.l4.2]
  3. The vertical distance between tops of domestic hot plates and laundry stoves and combustible materials shall be not less than 30 inches (762 mm). [NFPA 54:10.14.3]
Electric household cooking appliances designed for permanent installations shall be installed in accordance with the manufacturer's installation instructions. Household electric ranges shall comply with UL 858.
Gas-fired household cooking appliances shall comply with Section 921.3 through Section 921.4.4.
Floor mounted units shall be installed in accordance with Section 921.3.1 and Section 921.3.2.
The clearances specified as follows shall not interfere with combustion air, accessibility for operation, and servicing:
  1. Listed floor-mounted household cooking appliances, where installed on combustible floors, shall be set on their own bases or legs and shall be installed in accordance with their listing and the manufacturer's installation instructions.
  2. Listed household cooking appliances with listed gas room heater sections shall be installed so that the warm air discharge side shall have a clearance of not less than 18 inches (457 mm) from adjacent combustible material. A clearance of not less than 36 inches (914 mm) shall be provided between the top of the heater section and the bottom of cabinets.
  3. Listed household cooking appliances that include a solid or liquid fuel-burning section shall be spaced from combustible material and otherwise installed in accordance with their listing and the manufacturer's installation instructions for the supplementary fuel section of the appliance.
  4. Unlisted floor-mounted household cooking appliances shall be installed with not less than 6 inches (152 mm) clearance at the back and sides to combustible material. Combustible floors under unlisted appliances shall be protected in an approved manner.
Household cooking appliances shall have a vertical clearance above the cooking top of not less than 30 inches (762 mm) to combustible material or metal cabinets. A minimum clearance of 24 inches (610 mm) is permitted where one of the following is installed:
  1. The underside of the combustible material or metal cabinet above the cooking top is protected with not less than 14 of an inch (6.4 mm) insulating millboard covered with sheet metal not less than 0.0122 of an inch (0.3099 mm) thick.
  2. A metal ventilating hood of sheet metal not less than 0.0122 of an inch (0.3099 mm) thick is installed above the cooking top with a clearance of not less than 14 of an inch (6.4 mm) between the hood and the underside of the combustible material or metal cabinet, and the hood is as wide as the appliance and is centered over the appliance.
  3. A listed cooking appliance or microwave oven installed over a listed cooking appliance shall be in accordance with the terms of the upper appliance's listing and the manufacturer's installation instructions. Microwave ovens shall comply with UL 923.
Built-in units shall be installed in accordance with Section 921.4.1 through Section 921.4.4.
Listed built-in household cooking appliances shall be installed in accordance with their listing and the manufacturer's installation instructions. The installation shall not interfere with combustion air, accessibility for operation, and servicing. Unlisted built-in household cooking appliances shall not be installed in or adjacent to combustible material.
Built-in top (or surface) cooking appliances shall have a vertical clearance above the cooking top of not less than 30 inches (762 mm) to combustible material or metal cabinets. A clearance of not less than 24 inches (610 mm) is permitted where one of the following is installed:
  1. The underside of the combustible material or metal cabinet above the cooking top is protected with not less than 14 of an inch (6.4 mm) insulating millboard covered with sheet metal not less than 0.0122 of an inch (0.3099 mm) thick.
  2. A metal ventilating hood of sheet metal not less than 0.0122 of an inch (0.3099 mm) thick is installed above the cooking top with a clearance of not less than 14 of an inch (6.4 mm) between the hood and the underside of the combustible material or metal cabinet, and the hood not less than the width of the appliance and is centered over the appliance.
  3. A listed cooking appliance or microwave oven installed over a listed cooking appliance shall be in accordance with the terms of the upper appliance listing and the manufacturer's installation instructions.
The horizontal distance from the center of the burner head(s) of a listed top (or surface) cooking appliance to vertical combustible walls extending above the top panel shall be not less than that distance specified by the permanent marking on the appliance. [NFPA 54:10.15.2.3]
Built-in household cooking appliances shall be installed so that the cooking top, broiler pan, or oven racks are level. [NFPA 54:10.15.2.4]
Commercial electric ranges shall comply with UL 197 and installed in accordance with the manufacturer's installation instructions.
Commercial wood-fired baking ovens (refractory type) shall comply with UL 2162 and installed in accordance with the manufacturer's installation instructions.
Oil-burning ranges shall comply with UL 896 and installed in accordance with the manufacturer's installation instructions.
Listed open-top broiler units shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:10.19.1]
Unlisted open-top broiler units shall be installed in accordance with the manufacturer's installation instructions but shall not be installed in combustible material. [NFPA 54:10.19.2]
Domestic open-top broiler units shall be provided with a metal ventilating hood not less than 0.0122 of an inch (0.3099 mm) thick with a clearance of not less than 14 of an inch (6.4 mm) between the hood and the underside of combustible material or metal cabinets. A clearance of not less than 24 inches (610 mm) shall be maintained between the cooking top and the combustible material or metal cabinet, and the hood shall be as wide as the open-top broiler unit and centered over the unit. Listed domestic open-top broiler units incorporating an integral exhaust system and listed for use without a ventilating hood need not be provided with a ventilating hood where installed in accordance with Section 921.3.2(1). [NFPA 54:10.19.3]
Commercial open-top broiler units shall be provided with ventilation in accordance with Chapter 5. [NFPA 54:10.19.4]
Listed outdoor cooking appliances shall be installed in accordance with their listing and the manufacturer's installation instructions.
Unlisted outdoor cooking appliances shall be installed outdoors with clearances to combustible material of not less than 36 inches (914 mm) at the sides and back and not less than 48 inches (1219 mm) at the front. In no case shall the appliance be located under overhead combustible construction. [NFPA 54:10.20.2]
Listed illuminating appliances shall be installed in accordance with their listing and the manufacturer's installation instructions.
Unlisted illuminating appliances shall be installed with clearances in accordance with the following:
  1. Unlisted enclosed illuminating appliances installed outdoors shall be installed with clearances from combustible material of not less than 12 inches (305 mm). [NFPA 54:10.16.2.1(1)]
  2. Unlisted enclosed illuminating appliances installed indoors shall be installed with clearances from combustible material of not less than 18 inches (457 mm). [NFPA 54:10.16.2.1(2)]
Open-flame illuminating appliances shall be installed with clearances in accordance with the following:
  1. Unlisted open-flame illuminating appliances installed outdoors shall have clearances from combustible material not less than that specified in Table 925.2.1. The distance from ground level to the base of the burner shall be not less than 7 feet (2134 mm) where installed within 2 feet (610 mm) of walkways. Lesser clearances shall be permitted to be used where acceptable to the Authority Having Jurisdiction. [NFPA 54:10.16.2.2(1)]
  2. Unlisted open-flame illuminating appliances installed outdoors shall be equipped with a limiting orifice or other limiting devices that will maintain a flame height consistent with the clearance from combustible material in accordance with Table 925.2.1. [NFPA 54:10.16.2.2(2)]
  3. Appliances designed for flame heights in excess of 30 inches (762 mm) shall be permitted to be installed where acceptable to the Authority Having Jurisdiction. Such appliances shall be equipped with a safety shutoff device or automatic ignition. [NFPA 54:10.16.2.2(3)]
  4. Unlisted open-flame illuminating appliances installed indoors shall have clearances from combustible material acceptable to the Authority Having Jurisdiction. [NFPA 54:10.16.2.2(4)]

TABLE 925.2.1
CLEARANCES FOR UNLISTED OUTDOOR
OPEN-FLAME ILLUMINATING APPLIANCES
[NFPA 54: TABLE 10.16.2.2]
FLAME HEIGHT
ABOVE BURNER HEAD
(inches)
MINIMUM CLEARANCE FROM
COMBUSTIBLE MATERIAL (feet)*
HORIZONTAL VERTICAL
12 2 6
18 3 8
24 3 10
30 4 12
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
* Measured from the nearest portion of the burner head.
Illuminating appliances designed for wall or ceiling mounting shall be securely attached to structures in such a manner that they are not dependent on the gas piping for support. [NFPA 54:10.16.3]
Illuminating appliances designed for post mounting shall be securely and rigidly attached to a post. Posts shall be rigidly mounted. The strength and rigidity of posts exceeding 3 feet (914 mm) in height shall be not less than a 212 inch (64 mm) diameter post constructed of 0.064 of an inch (1.626 mm) thick steel or a 1 inch (25.4 mm) Schedule 40 steel pipe. Posts 3 feet (914 mm) or less in height shall not be smaller than a 34 of an inch (19.1 mm) Schedule 40 steel pipe. Drain openings shall be provided near the base of posts where there is a possibility of water collecting inside them. [NFPA 54:10.16.4]
Where an appliance pressure regulator is not supplied with an illuminating appliance and the service line is not equipped with a service pressure regulator, an appliance pressure regulator shall be installed in the line serving one or more illuminating appliances. [NFPA 54:10.16.5]
Field constructed commercial-industrial incinerators shall be constructed and installed in accordance with NFPA 82.
Factorybuilt commercial incinerators and crematories shall comply with UL 2790 and installed in accordance with the manufacturer's installation instructions.
Residential incinerators shall comply with UL 791 and installed in accordance with the manufacturer's installation instructions.
Suspended-type infrared heaters shall be fixed in position independent of gas and electric supply lines. Hangers and brackets shall be of noncombustible material. Heaters subject to vibration shall be provided with vibration-isolating hangers. [NFPA 54:10.18.1]
Suspended low-intensity infrared tube heaters shall be connected to the building piping system with a connector listed for the application in accordance with CSA Z21.24 as follows:
  1. The connector shall be installed in accordance with the tube heater installation instructions, and shall be in the same room as the appliance.
  2. One connector shall be used per appliance. [NFPA 54:9.6.1.3]
The installation of infrared heaters shall comply with the following clearance requirements:
  1. Listed heaters shall be installed with clearances from combustible material in accordance with their listing and the manufacturer's installation instructions.
  2. Unlisted heaters shall be installed in accordance with clearances from combustible material acceptable to the Authority Having Jurisdiction.
  3. In locations used for the storage of combustible materials, signs shall be posted to specify the maximum permissible stacking height to maintain required clearances from the heater to the combustibles.
Combustion and ventilation air for infrared heaters shall be provided in accordance with the following:
  1. Where unvented infrared heaters are used, natural or mechanical means shall be provided to supply and exhaust not less than 4 cubic teet per minute per 1000 British thermal units per hour [(ft3/min)/(Blu/h)] [0.4 (m3/min)/kW] input of installed heaters. [NFPA 54:10.18.3.1]
  2. Exhaust openings for removing flue products shall be above the level of the heaters. [NFPA 54:10.18.3.2]
Overhead heaters installed in garages for more than three motor vehicles or in aircraft hangars shall be of a listed type and shall be installed in accordance with Section 905.8 and Section 905.9. [NFPA 54:10.18.4]
A pool heater shall be located or protected so as to minimize accidental contact of hot surfaces by persons. [NFPA 54:10.21.1]
The installation of pool heaters shall comply with the following requirements:
  1. In no case shall the clearances be such as to interfere with combustion air, draft hood, or vent terminal clearance and relief, and accessibility for servicing.
  2. A listed pool heater shall be installed in accordance with its listing and the manufacturer's installation instructions.
  3. An unlisted pool heater shall be installed with a clearance of not less than 12 inches (305 mm) on the sides and the rear. A combustible floor under an unlisted pool heater shall be protected in an approved manner.
Pool heaters shall be provided with temperature or pressure-limiting devices in accordance with the following:
  1. An unlisted pool heater shall be provided with overtemperature protection or overtemperature and overpressure protection by means of an approved device(s). [NFPA 54:10.21.3.1]
  2. Where a pool heater is provided with over-temperature protection and is installed with a device in the discharge line of the heater that is capable of restricting the flow of water from the heater to the pool (such as a check valve, shutoff valve, therapeutic pool valving, or flow nozzles), a pressure-relief valve shall be installed either in the heater or between the heater and the restrictive device. [NFPA 54:10.21.3.2]
Where an integral bypass system is not provided as a part of the pool heater, a bypass line and valve shall be installed between the inlet and outlet piping for use in adjusting the now of water through the heater. [NFPA 54:10.21.4]
A pool heater listed for outdoor installation shall be installed with the venting means supplied by the manufacturer and in accordance with the manufacturer's installation instructions. [NFPA 54:10.21.5] (See Section 802.2.4, Section 802.2.5, Section 802.3.3, and Section 802.8 through Section 802.8.5)
Refrigerators shall be provided with clearances for ventilation at the top and back in accordance with the manufacturer's instructions. Where such instructions are not available, not less than 2 inches (51 mm) shall be provided between the back of the refrigerator and the wall and not less than 12 inches (305 mm) above the top. [NFPA 54:10.22.1]
Where an accessory kit is used for conveying air for burner combustion or unit cooling to the refrigerator from areas outside the room in which it is located, or for conveying combustion products diluted with air containing waste heat from the refrigerator to areas outside the room in which it is located, the kit shall be installed in accordance with the refrigerator manufacturer's installation instructions. [NFPA 54:10.22.2]
A listed gas-fired toilet shall be installed in accordance with its listing and the manufacturer's installation instructions, provided that the clearance shall be such to afford ready accessibility for use, cleanout, and necessary servicing.
Listed gas-fired toilets installed on combustible floors shall be listed for such installation. [NFPA 54:10.25.2]
Vents or vent connectors that are capable of being contacted during casual use of the room in which the toilet is installed shall be protected or shielded to prevent such contact. [NFPA 54:10.25.3]
Appliances installed in manufactured housing after the initial sale shall be listed for installation in manufactured housing, or approved, and shall be installed in accordance with the requirements of this code and the manufacturer's installation instructions. Appliances installed in the living space of manufactured housing shall be in accordance with the requirements of Section 701.0. [NFPA 54:10.30]
The provisions of this section apply to kilns used for ceramics that have a maximum interior volume of 20 cubic feet (0.57 m3) and are used for hobby or noncommercial purposes.
Kilns shall be installed in accordance with the manufacturer's installation instructions and the provisions of this code.
Fuel-gas controls shall comply with Section 306.0 and Section 902.4. Standing pilots shall not be used with gas-fired kilns.
All electrical equipment used as part of, or in connection with, the installation of a kiln shall be in accordance with the requirements in the electrical code.
In addition to other requirements specified in this section, interior installations shall comply with the requirements of Section 932.5.1 through Section 932.5.5.
The sides and tops of kilns shall be located not less than 18 inches (457 mm) from a noncombustible wall surface and 3 feet (914 mm) from a combustible wall surface. Kilns shall be installed on noncombustible flooring consisting of not less than 2 inches (51 mm) of solid masonry or concrete extending not less than 12 inches (305 mm) beyond the base or supporting members of the kiln.

Exception: These clearances shall be permitted to be reduced, provided the kiln is installed in accordance with its listing.

    In no case shall the clearance on the gas or electrical control side of a kiln be reduced to less than 30 inches (762 mm).
A canopy-type hood shall be installed directly above each kiln. The face opening area of the hood shall be equal to or greater than the top horizontal surface area of the kiln. The hood shall be constructed of not less than 0.024 of an inch (0.61 mm) (No. 24 gauge) galvanized steel or equivalent and be supported at a height of between 12 inches (305 mm) and 30 inches (762 mm) above the kiln by noncombustible supports.

Exception: Electric kilns installed with listed exhaust blowers shall be permitted to be used where marked as being suitable for the kiln and installed in accordance with the manufacturer's installation instructions.
Each hood shall be connected to a gravity ventilation duct extending in a vertical direction to outside the building. This duct shall be of the same construction as the hood and shall have a minimum cross-sectional area of not less than one-fifteenth of the face opening area of the hood. The duct shall terminate not less than 12 inches (305 mm) above a portion of a building within 4 feet (1219 mm) and terminate not less than 4 feet (1219 mm) from an openable window or other opening into the building or adjacent property line. The duct opening to the outside shall be shielded, without reduction of duct area, to prevent entrance of rain into the duct. The duct shall be supported at each section by noncombustible supports.
Provisions shall be made for air to enter the room in which a kiln is installed at a rate not less than the air being removed through the kiln hood.
A hood and duct serving a fuel-burning kiln shall have a clearance from combustible construction of not less than 18 inches (457 mm). This clearance shall be permitted to be reduced in accordance with Table 303.10.1.
Kilns shall be installed with minimum clearances as specified in Section 932.5.1. Wherever a kiln is located under a roofed area and is partially enclosed by more than two vertical wall surfaces, a hood and gravity ventilation duct shall be installed in accordance with Section 932.5.2, Section 932.5.3, and Section 932.5.5.
Permanently fixed in place outdoor open flame decorative appliances shall be installed in accordance with Section 933.1.1 through Section 933.1.3. [NFPA 54:10.32]
Listed outdoor open flame decorative appliances shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:10.32.1]
Unlisted outdoor open flame decorative appliances shall be installed outdoors in accordance with the manufacturer's installation instructions and with clearances to combustible material of not less than 36 inches (914 mm) from the sides. In no case shall the appliance be located under overhead combustible construction. [NFPA 54:10.32.2]
The connection to the gas piping system shall comply with Section 1313.1(1), Section 1313.1(2), Section 1313.1(4), or Section 1313.1(5). [NFPA 54:10.32.3]
Evaporative cooling systems, including air ducts and fire dampers that are a portion of an evaporative cooling system, shall be in accordance with Section 934.2 through Section 934.4.3. Evaporative cooling systems shall be provided with outside air as specified for cooling systems in Section 403.0.
Evaporative cooling systems shall be installed so as to minimize the probability of damage from an external source.
Evaporative coolers shall be accessible for inspection, service, and replacement without removing permanent construction.
An evaporative cooler supported by the building structure shall be installed on a level base and shall be secured directly or indirectly to the building structure, to prevent displacement of the cooler.
Modifications made to the supporting framework of buildings as a result of the installation shall be in accordance with the requirements of the building code. Openings in exterior walls shall be flashed in an approved manner in accordance with the requirements of the building code.
An evaporative cooler supported directly by the ground shall be isolated from the ground by a level concrete slab extending not less than 3 inches (76 mm) above the adjoining ground level.
An evaporative cooler supported on an aboveground platform shall be elevated not less than 6 inches (152 mm) above adjoining ground level.
Factory-built commercial refrigerators and freezers shall comply with UL 471 and installed in accordance with the manufacturer's installation instructions.
Factory-built unit coolers for use in refrigerators, freezers, refrigerated warehouses, and walk-in coolers shall comply with UL 412 and installed in accordance with the manufacturer's installation instructions.
Self-contained mechanical refrigeration systems for use in walk-in coolers shall comply with UL 427 and installed in accordance with the manufacturer's installation instructions.
A ductless mini-split system installation shall be installed in accordance with the manufacturer's installation instructions and Section 310.2 for condensate control.
Electrostatic air cleaners shall comply with UL 867 and installed in accordance with the manufacturer's installation instructions.
High-et1iciency particulate air filter units for use in industrial and laboratory exhaust and ventilation systems shall be installed in accordance with the manufacturer's installation instructions.
Gaseous hydrogen systems shall be installed in accordance with NFPA 2.
The installation of compressed natural gas (CNG) fueling (dispensing) systems shall comply with NFPA 52. [NFPA 54:10.29]
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