This code shall apply to the installation of fuel gas piping systems, fuel gas utilization equipment, and related accessories as follows:
- Coverage of piping systems shall extend from the point of delivery to the connections with gas utilization equipment. (See “point of delivery.”)
- Piping systems requirements shall include design, materials, components, fabrication, assembly, installation, testing and inspection.
- Requirements for gas utilization equipment and related accessories shall include installation, combustion and ventilation air and venting.
This code shall not apply to the following:
- Portable LP-Gas equipment of all types that are not connected to a fixed fuel piping system.
- Installation of farm equipment such as brooders, dehydrators, dryers, and irrigation equipment.
- Raw material (feedstock) applications except for piping to special atmosphere generators.
- Oxygen-fuel gas cutting and welding systems.
- Industrial gas applications using gases such as acetylene and acetylenic compounds, hydrogen, ammonia, carbon monoxide, oxygen, and nitrogen.
- Petroleum refineries, pipeline compressor or pumping stations, loading terminals, compounding plants, refinery tank farms, and natural gas processing plants.
- Integrated chemical plants or portions of such plants where flammable or combustible liquids or gases are produced by chemical reactions or used in chemical reactions.
- LP-Gas installations at utility gas plants.
- Liquefied natural gas (LNG) installations.
- Fuel gas piping in power and atomic energy plants.
- Proprietary items of equipment, apparatus, or instruments such as gas generating sets, compressors, and calorimeters.
- LP-Gas equipment for vaporization, gas mixing, and gas manufacturing.
- Temporary LP-Gas piping for buildings under construction or renovation that is not to become part of the permanent piping system.
- Installation of LP-Gas systems for railroad switch heating.
- Installation of LP-Gas and compressed natural gas (CNG) systems on vehicles.
- Except as provided in Section 401.1.1, gas piping, meters, gas pressure regulators, and other appurtenances used by the serving gas supplier in the distribution of gas, other than undiluted LP-Gas.
- Building design and construction, except as specified herein.
For structures located in flood hazard areas, the appliance, equipment and system installations regulated by this code shall be located at or above the elevation required by Section 1612 of the International Building Code for utilities and attendant equipment.
Exception: The appliance, equipment and system installations regulated by this code are permitted to be located below the elevation required by Section 1612 of the International Building Code for utilities and attendant equipment provided that they are designed and installed to prevent water from entering or accumulating within the components and to resist hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of flooding to such elevation.
The appliances, equipment and systems regulated by this code shall not be located in an elevator shaft.
Appliances shall not be located in sleeping rooms, bathrooms, toilet rooms, storage closets or surgical rooms, or in a space that opens only into such rooms or spaces, except where the installation complies with one of the following:
- The appliance is a direct-vent appliance installed in accordance with the conditions of the listing and the manufacturer’s instructions.
- Vented room heaters, wall furnaces, vented decorative appliances, vented gas fireplaces, vented gas fireplace heaters and decorative appliances for installation in vented solid fuel-burning fireplaces are installed in rooms that meet the required volume criteria of Section 304.5.
- A single wall-mounted unvented room heater is installed in a bathroom and such unvented room heater is equipped as specified in Section 621.6 and has an input rating not greater than 6,000 Btu/h (1.76 kW). The bathroom shall meet the required volume criteria of Section 304.5.
- A single wall-mounted unvented room heater is installed in a bedroom and such unvented room heater is equipped as specified in Section 621.6 and has an input rating not greater than 10,000 Btu/h (2.93 kW). The bedroom shall meet the required volume criteria of Section 304.5.
- The appliance is installed in a room or space that opens only into a bedroom or bathroom, and such room or space is used for no other purpose and is provided with a solid weather-stripped door equipped with an approved self-closing device. All combustion air shall be taken directly from the outdoors in accordance with Section 304.6.
Air for combustion, ventilation and dilution of flue gases for appliances installed in buildings shall be provided by application of one of the methods prescribed in Sections 304.5 through 304.9. Where the requirements of Section 304.5 are not met, outdoor air shall be introduced in accordance with one of the methods prescribed in Sections 304.6 through 304.9. Direct-vent appliances, gas appliances of other than natural draft design and vented gas appliances other than Category I shall be provided with combustion, ventilation and dilution air in accordance with the appliance manufacturer’s instructions.
Exception: Type 1 clothes dryers that are provided with makeup air in accordance with Section 614.5.
Where the air infiltration rate of a structure is known, the minimum required volume shall be determined as follows:
For appliances other than fan-assisted, calculate volume using Equation 3-1.
For fan-assisted appliances, calculate volume using Equation 3-2.
|Iother||=||All appliances other than fan assisted (input in Btu/h).|
|Ifan||=||Fan-assisted appliance (input in Btu/h).|
|ACH||=||Air change per hour (percent of volume of space exchanged per hour, expressed as a decimal).|
For purposes of this calculation, an infiltration rate greater than 0.60 ACH shall not be used in Equations 3-1 and 3-2.
Two permanent openings, one commencing within 12 inches (305 mm) of the top and one commencing within 12 inches (305 mm) of the bottom of the enclosure, shall be provided. The openings shall communicate directly, or by ducts, with the outdoors or spaces that freely communicate with the outdoors.
Where directly communicating with the outdoors, or where communicating with the outdoors through vertical ducts, each opening shall have a minimum free area of 1 square inch per 4,000 Btu/h (550 mm2/kW) of total input rating of all appliances in the enclosure [see Figures 304.6.1(1) and 304.6.1(2)].
Where communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of not less than 1 square inch per 2,000 Btu/h (1,100 mm2/kW) of total input rating of all appliances in the enclosure [see Figure 304.6.1(3)].
One permanent opening, commencing within 12 inches (305 mm) of the top of the enclosure, shall be provided. The appliance shall have clearances of at least 1 inch (25 mm) from the sides and back and 6 inches (152 mm) from the front of the appliance. The opening shall directly communicate with the outdoors or through a vertical or horizontal duct to the outdoors, or spaces that freely communicate with the outdoors (see Figure 304.6.2) and shall have a minimum free area of 1 square inch per 3,000 Btu/h (734 mm2/kW) of the total input rating of all appliances located in the enclosure and not less than the sum of the areas of all vent connectors in the space.
The outdoor opening(s) size shall be calculated in accordance with the following:
- The ratio of interior spaces shall be the available volume of all communicating spaces divided by the required volume.
- The outdoor size reduction factor shall be one minus the ratio of interior spaces.
- The minimum size of outdoor opening(s) shall be the full size of outdoor opening(s) calculated in accordance with Section 304.6, multiplied by the reduction factor. The minimum dimension of air openings shall be not less than 3 inches (76 mm).
Combustion air ducts shall comply with all of the following:
- Ducts shall terminate in an unobstructed space allowing free movement of combustion air to the appliances.
- Ducts shall serve a single enclosure.
- Ducts shall not serve both upper and lower combustion air openings where both such openings are used. The separation between ducts serving upper and lower combustion air openings shall be maintained to the source of combustion air.
- Ducts shall not be screened where terminating in an attic space.
- Horizontal upper combustion air ducts shall not slope downward toward the source of combustion air.
- Combustion air intake openings located on the exterior of a building shall have the lowest side of such openings located not less than 12 inches (305 mm) vertically from the adjoining finished ground level.
Where corrosive or flammable process fumes or gases, other than products of combustion, are present, means for the disposal of such fumes or gases shall be provided. Such fumes or gases include carbon monoxide, hydrogen sulfide, ammonia, chlorine and halogenated hydrocarbons.
In barbershops, beauty shops and other facilities where chemicals that generate corrosive or flammable products, such as aerosol sprays, are routinely used, nondirect vent-type appliances shall be located in a mechanical room separated or partitioned off from other areas with provisions for combustion air and dilution air from the outdoors. Direct-vent appliances shall be installed in accordance with the appliance manufacturer’s installation instructions.
Equipment and appliances shall be installed as required by the terms of their approval, in accordance with the conditions of listing, the manufacturer’s instructions and this code. Manufacturers’ installation instructions shall be available on the job site at the time of inspection. Where a code provision is less restrictive than the conditions of the listing of the equipment or appliance or the manufacturer’s installation instructions, the conditions of the listing and the manufacturer’s installation instructions shall apply.
Unlisted appliances approved in accordance with Section 301.3 shall be limited to uses recommended by the manufacturer and shall be installed in accordance with the manufacturer’s instructions, the provisions of this code and the requirements determined by the code official.
Equipment and appliances having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457 mm) above the floor in hazardous locations and public garages, private garages, repair garages, motor fuel-dispensing facilities and parking garages. For the purpose of this section, rooms or spaces that are not part of the living space of a dwelling unit and that communicate directly with a private garage through openings shall be considered to be part of the private garage.
Exception: Elevation of the ignition source is not required for appliances that are listed as flammable vapor ignition resistant.
Connection of a parking garage with any room in which there is a fuel-fired appliance shall be by means of a vestibule providing a two-doorway separation, except that a single door is permitted where the sources of ignition in the appliance are elevated in accordance with Section 305.3.
Exception: This section shall not apply to appliance installations complying with Section 305.4.
Appliances located in public garages, motor fuel-dispensing facilities, repair garages or other areas frequented by motor vehicles shall be installed a minimum of 8 feet (2438 mm) above the floor. Where motor vehicles are capable of passing under an appliance, the appliance shall be installed at the clearances required by the appliance manufacturer and not less than 1 foot (305 mm) higher than the tallest vehicle garage door opening.
Exception: The requirements of this section shall not apply where the appliances are protected from motor vehicle impact and installed in accordance with Section 305.3 and NFPA 30A.
Appliances located in private garages shall be installed with a minimum clearance of 6 feet (1829 mm) above the floor.
Exception: The requirements of this section shall not apply where the appliances are protected from motor vehicle impact and installed in accordance with Section 305.3.
Appliances installed in repair garages shall be installed in a detached building or room, separated from repair areas by walls or 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 the outdoors. The appliance room shall not be used for the storage of combustible materials.
- Overhead heaters where installed not less than 8 feet (2438 mm) above the floor shall be permitted.
- Heating appliances for vehicle repair areas where there is no dispensing or transferring of Class I or II flammable or combustible liquids or liquefied petroleum gas shall be installed in accordance with NFPA 30A.
Rooms containing appliances shall be provided with a door and an unobstructed passageway measuring not less than 36 inches (914 mm) wide and 80 inches (2032 mm) high.
Exception: Within a dwelling unit, appliances installed in a compartment, alcove, basement or similar space shall be provided with access by an opening or door and an unobstructed passageway measuring not less than 24 inches (610 mm) wide and large enough to allow removal of the largest appliance in the space, provided that a level service space of not less than 30 inches (762 mm) deep and the height of the appliance, but not less than 30 inches (762 mm), is present at the front or service side of the appliance with the door open.
Attics containing appliances shall be provided with an opening and unobstructed passageway large enough to allow removal of the largest appliance. The passageway shall not be less than 30 inches (762 mm) high and 22 inches (559 mm) wide and not more than 20 feet (6096 mm) in length measured along the centerline of the passageway from the opening to the appliance. The passageway shall have continuous solid flooring not less than 24 inches (610 mm) wide. A level service space not less than 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present at the front or service side of the appliance. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches (508 mm by 762 mm), and large enough to allow removal of the largest appliance.
- The passageway and level service space are not required where the appliance is capable of being serviced and removed through the required opening.
- Where the passageway is not less than 6 feet (1829 mm) high for its entire length, the passageway shall be not greater than 50 feet (15 250 mm) in length.
Under-floor spaces containing appliances shall be provided with an access opening and unobstructed passageway large enough to remove the largest appliance. The passageway shall not be less than 30 inches (762 mm) high and 22 inches (559 mm) wide, nor more than 20 feet (6096 mm) in length measured along the centerline of the passageway from the opening to the appliance. A level service space not less than 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present at the front or service side of the appliance. If the depth of the passageway or the service space exceeds 12 inches (305 mm) below the adjoining grade, the walls of the passageway shall be lined with concrete or masonry extending 4 inches (102 mm) above the adjoining grade and having sufficient lateral-bearing capacity to resist collapse. The clear access opening dimensions shall be a minimum of 22 inches by 30 inches (559 mm by 762 mm), and large enough to allow removal of the largest appliance.
- The passageway is not required where the level service space is present when the access is open and the appliance is capable of being serviced and removed through the required opening.
- Where the passageway is not less than 6 feet high (1829 mm) for its entire length, the passageway shall not be limited in length.
Where equipment requiring access or appliances are located on an elevated structure or the roof of a building such that personnel will have to climb higher than 16 feet (4877 mm) above grade to access such equipment or appliances, an interior or exterior means of access shall be provided. Such access shall not require climbing over obstructions greater than 30 inches (762 mm) in height or walking on roofs having a slope greater than 4 units vertical in 12 units horizontal (33-percent slope). Such access shall not require the use of portable ladders.
Permanent ladders installed to provide the required access shall comply with the following minimum design criteria:
- The side railing shall extend above the parapet or roof edge not less than 30 inches (762 mm).
- Ladders shall have rung spacing not to exceed 14 inches (356 mm) on center. The upper-most rung shall be a maximum of 24 inches (610 mm) below the upper edge of the roof hatch, roof or parapet, as applicable.
- Ladders shall have a toe spacing not less than 6 inches (152 mm) deep.
- There shall be a minimum of 18 inches (457 mm) between rails.
- Rungs shall have a minimum 0.75-inch (19 mm) diameter and be capable of withstanding a 300-pound (136.1 kg) load.
- Ladders over 30 feet (9144 mm) in height shall be provided with offset sections and landings capable of withstanding 100 pounds per square foot (488.2 kg/m2). Landing dimensions shall be not less than 18 inches (457 mm) and not less than the width of the ladder served. A guard rail shall be provided on all open sides of the landing.
- Climbing clearance. The distance from the centerline of the rungs to the nearest permanent object on the climbing side of the ladder shall be a minimum of 30 inches (762 mm) measured perpendicular to the rungs. This distance shall be maintained from the point of ladder access to the bottom of the roof hatch. A minimum clear width of 15 inches (381 mm) shall be provided on both sides of the ladder measured from the midpoint of and parallel with the rungs except where cages or wells are installed.
- Landing required. The ladder shall be provided with a clear and unobstructed bottom landing area having a minimum dimension of 30 inches (762 mm) by 30 inches (762 mm) centered in front of the ladder.
- Ladders shall be protected against corrosion by approved means.
- Access to ladders shall be provided at all times.
Exception: This section shall not apply to Group R-3 occupancies.
Category IV condensing appliances shall be provided with an auxiliary drain pan where damage to any building component will occur as a result of stoppage in the condensate drainage system. Such pan shall be installed in accordance with the applicable provisions of Section 307 of the International Mechanical Code.
Exception: An auxiliary drain pan shall not be required for appliances that automatically shut down operation in the event of a stoppage in the condensate drainage system.
The allowable clearance reduction shall be based on one of the methods specified in Table 308.2 or shall utilize an assembly listed for such application. Where required clearances are not listed in Table 308.2, the reduced clearances shall be determined by linear interpolation between the distances listed in the table. Reduced clearances shall not be derived by extrapolation below the range of the table. The reduction of the required clearances to combustibles for listed and labeled appliances and equipment shall be in accordance with the requirements of this section except that such clearances shall not be reduced where reduction is specifically prohibited by the terms of the appliance or equipment listing [see Figures 308.2(1) through 308.2(3)].
TABLE 308.2 a through k
REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTION
|TYPE OF PROTECTION APPLIED TO |
AND COVERING ALL SURFACES OF COMBUSTIBLE
MATERIAL WITHIN THE DISTANCE SPECIFIED AS THE
REQUIRED CLEARANCE WITH NO PROTECTION[see Figures 308.2(1), 308.2(2), and 308.2(3)]
|WHERE THE REQUIRED CLEARANCE WITH NO PROTECTION FROM |
APPLIANCE, VENT CONNECTOR, OR SINGLE-WALL METAL PIPE IS: (inches)
|Allowable clearances with specified protection (inches)|
|Use Column 1 for clearances above appliance or horizontal connector. Use Column 2 |
for clearances from appliance, vertical connector and single-wall metal pipe.
and rearCol. 2
and rearCol. 2
and rearCol. 2
and rearCol. 2
and rearCol. 2
|1. 31/2-inch-thick masonry wall without ventilated |
|2. 1/2-inch insulation board over 1-inch glass fiber or |
mineral wool batts
|3. 0.024-inch (nominal 24 gage) sheet metal over 1-inch |
glass fiber or mineral wool batts reinforced with wireon rear face with ventilated airspace
|4. 31/2-inch-thick masonry wall with |
|5. 0.024-inch (nominal 24 gage) sheet metal with |
|6. 1/2-inch-thick insulation board with ventilated |
|7. 0.024-inch (nominal 24 gage) sheet metal with |
ventilated airspace over 0.024-inch (nominal 24 gage)sheet metal with ventilated airspace
|8. 1-inch glass fiber or mineral wool batts sandwiched |
between two sheets 0.024-inch (nominal 24 gage)sheet metal with ventilated airspace
For SI: 1 inch = 25.4 mm, °C = [(°F - 32)/1.8], 1 pound per cubic foot = 16.02 kg/m3, 1 Btu per inch per square foot per hour per °F = 0.144 W/m2 • K.
- Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.
- All clearances shall be measured from the outer surface of the combustible material to the nearest point on the surface of the appliance, disregarding any intervening protection applied to the combustible material.
- Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite an appliance or connector.
- For all clearance reduction systems using a ventilated airspace, adequate provision for air circulation shall be provided as described [see Figures 308.2(2) and 308.2(3)].
- There shall be at least 1 inch between clearance reduction systems and combustible walls and ceilings for reduction systems using ventilated airspace.
- Where a wall protector is mounted on a single flat wall away from corners, it shall have a minimum 1-inch air gap. To provide air circulation, the bottom and top edges, or only the side and top edges, or all edges shall be left open.
- Mineral wool batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum melting point of 1500°F.
- Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu per inch per square foot per hour per °F or less.
- There shall be at least 1 inch between the appliance and the protector. In no case shall the clearance between the appliance and the combustible surface be reduced below that allowed in this table.
- All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.
- Listed single-wall connectors shall be installed in accordance with the manufacturer’s installation instructions.