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

The regulations of this chapter shall govern the installation of fuel gas piping in or in connection with a building, structure or within the property lines of premises up to 5 pounds-force per square inch (psi) (34 kPa), other than service pipe. Fuel oil piping systems shall be installed in accordance with NFPA 31.
Coverage of piping systems shall extend from the point of delivery to the appliance connections. For other than undiluted liquefied petroleum gas systems (LP-Gas), the point of delivery shall be the outlet of the service meter assembly or the outlet of the service regulator or service shutoff valve where no meter is provided. For undiluted liquefied petroleum gas systems, the point of delivery shall be considered the outlet of the final pressure regulator, exclusive of the line gas regulators where no meter is installed. Where a meter is installed, the point of delivery shall be the outlet of the meter. [NFPA 54:1.1.1.1(A)]
Piping systems requirements shall include design, materials, components, fabrications, assembly, installation, testing, inspection, operation, and maintenance. [NFPA 54:1.1.1.1(C)]
This code shall not apply to the following (reference standards for some of which appear in Chapter 17):
  1. Portable LP-Gas appliances and equipment that are not connected to a fixed fuel piping system.
  2. Installation of appliances such as brooders, dehydrators, dryers, and irrigation equipment used for agricultural purposes.
  3. Raw material (feedstock) applications except for piping to special atmosphere generators.
  4. Oxygen-fuel gas cutting and welding systems.
  5. Industrial gas applications using such gases as acetylene and acctylenic compounds, hydrogen, ammonia, carbon monoxide, oxygen, and nitrogen.
  6. Petroleum refineries, pipeline compressor or pumping stations, loading terminals, compounding plants, refinery tank farms, and natural gas processing plants.
  7. Large 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.
  8. LP-Gas installations at utility gas plants.
  9. Liquefied natural gas (LNG) installations.
  10. Fuel gas piping in electric utility power plants.
  11. Proprietary items of equipment, apparatus, or instruments, such as gas-generating sets, compressors, and calorimeters.
  12. LP-Gas equipment for vaporization, gas mixing, and gas manufacturing.
  13. LP-Gas piping for buildings under construction or renovations that are not to become part of the permanent building piping system-that is, temporary fixed piping for building heat.
  14. Installation of LP-Gas systems for railroad switch heating.
  15. Installation of LP-Gas and compressed natural gas (CNG) systems on vehicles.
  16. Gas piping, meters, gas-pressure regulators, and other appurtenances used by the serving gas supplier in distribution of gas, other than undiluted LP-Gas. [NFPA 54:1.1.1.2]
Upon completion of the installation, alteration, or repair of gas piping, and prior to the use thereof, the Authority Having Jurisdiction shall be notified that such gas piping is ready for inspection.
Excavations required for the installation of underground piping shall be kept open until such time as the piping has been inspected and approved. Where such piping is covered or concealed before such approval, it shall be exposed upon the direction of the Authority Having Jurisdiction.
The Authority Having Jurisdiction shall make the following inspections and either shall approve that portion of the work as completed, or shall notify the permit holder wherein the same fails to be in accordance with this code.
This inspection shall be made after gas piping authorized by the permit has been installed before such piping has been covered or concealed, or before fixture or appliance has been attached thereto. This inspection shall include a determination that the gas piping size, material, and installation meet the requirements of this code.
This inspection shall be made after piping authorized by the permit has been installed and after portions thereof that are to be covered or concealed are so concealed and before fixture, appliance, or shutoff valve has been attached thereto. This inspection shall comply with Section 1314.1. Test gauges used in conducting tests shall be in accordance with Section 1303.3.3 through Section 1303.3.3.4.
Tests required by this code, which are performed utilizing dial gauges, shall be limited to gauges having the following pressure graduations or increments.
Required pressure tests of 10 psi (69 kPa) or less shall be performed with gauges of 0.10 psi (0.69 kPa) increments or less.
Required pressure tests exceeding 10 psi (69 kPa) but less than or equal to 100 psi (689 kPa) shall be performed with gauges of 1 psi (7 kPa) increments or less.
Required pressure tests exceeding 100 psi (689 kPa) shall be performed with gauges of 2 percent increments or less of the required test pressure.
Test gauges shall have a pressure range not exceeding twice the test pressure applied.
In cases where the work authorized by the permit consists of a minor installation of additional piping to piping already connected to a gas meter, the foregoing inspections shall be permitted to be waived at the discretion of the Authority Having Jurisdiction. In this event, the Authority Having Jurisdiction shall make such inspection as deemed advisable in order to be assured that the work has been performed in accordance with the intent of this code.
Where upon final piping inspection, the installation is found to be in accordance with the provisions of this code, a cel1ificate of inspection shall be permitted to be issued by the Authority Having Jurisdiction.
A copy of the certificate of such final piping inspection shall be issued to the serving gas supplier supplying gas to the premises.
It shall be unlawful for a serving gas supplier or person furnishing gas, to tum on or cause to be turned on, fuel gas or a gas meter or meters until such certificate of final inspection, as herein provided, has been issued.
It shall be unlawful for a person, firm, or corporation, excepting an authorized agent or employee of a person, firm, or corporation engaged in the business of furnishing or supplying gas and whose service pipes supply or connect with the particular premises, to tum on or reconnect gas service in or on a premises where gas service is, at the time, not being rendered.
It shall be unlawful to turn on or connect gas in or on the premises unless outlets are securely connected to gas appliances or capped or plugged with screw joint fittings.
The Authority Having Jurisdiction or the serving gas supplier is hereby authorized to disconnect gas piping or appliance or both that shall be found not to be in accordance with the requirements of this code or that are found defective and in such condition as to endanger life or property.
Where such disconnection has been made, a notice shall be attached to such gas piping or appliance or both that shall state the same has been disconnected, together with the reasons thereof.
It shall be unlawful to remove or disconnect gas piping or gas appliance without capping or plugging with a screw joint fitting, the outlet from which said pipe or appliance was removed. Outlets to which gas appliances are not connected shall be left capped and gastight on a piping system that has been installed, altered, or repaired.

Exception: Where an approved listed quick-disconnect device is used.
Where temporary use of gas is desired and the Authority Having Jurisdiction deems the use necessary, a permit shall be permitted to be issued for such use for a period of time not to exceed that designated by the Authority Having Jurisdiction, provided that such gas piping system otherwise is in accordance with to the requirements of this code regarding material, sizing, and safety.
Where required by the Authority Having Jurisdiction, a piping sketch or plan shall be prepared before proceeding with the installation. This plan shall show the proposed location of piping, the size of different branches, the various load demands, and the location of the point of delivery. [NFPA 54:5.1.1]
Where additional appliances are being connected to a gas piping system, the existing piping shall be checked to determine whether it has adequate capacity. Where inadequate, the existing system shall be enlarged as required, or separate gas piping of approved capacity shall be provided. [NFPA 54:5.1.2]
The location of the point of delivery shall be acceptable to the serving gas supplier. [NFPA 54:5.2]
Where two or more meters, or two or more service regulators where meters are not provided, are located on the same premises and supply separate users, the gas piping systems shall not be interconnected on the outlet side of the meters or service regulators. [NFPA 54:5.3.1]
Where a supplementary gas for standby use is connected downstream from a meter or a service regulator where a meter is not provided, a device to prevent backflow shall be installed. A three-way valve installed to admit the standby supply, and at the same time shut off the regular supply, shall be permitted to be used for this purpose. [NFPA 54:5.3.2]
Gas piping systems shall be of such size and so installed as to provide a supply of gas to meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply pressure required by the appliance. [NFPA 54:5.4.1]
The volumetric flow rate of gas to be provided (in cubic feet per hour) shall be calculated using the manufacturer's input ratings of the appliance served, adjusted for altitude. Where the input rating is not indicated, the gas supplier, appliance manufacturer, or a qualified agency shall be contacted or the rating from Table 1308.4.1 shall be used for estimating the volumetric flow rate of gas to be supplied.

    The total connected hourly load shall be used as the basis for pipe sizing, assuming the appliances are operating at full capacity simultaneously.

Exception: Sizing shall be permitted to be based upon established load diversity factors. [NFPA 54:5.4.2]

TABLE 1308.4.1
APPROXIMATE GAS INPUT FOR TYPICAL APPLIANCES
[NFPA 54: TABLE 5.4.2.1]
APPLIANCE INPUT
(Btu/h approx.)
Space Heating Units

Warm air furnace

Single family

Multifamily, per unit

Hydronic boiler

Single family

Multifamily, per unit




100000

60000



100000

60000
Space and Water Heating Units

Hydronic boiler

Single family

Multifamily, per unit




120000

75000
Water Heating Appliances

Water heater, automatic storage
30 to 40 gallon tank

Water heater, automatic storage
50 gallon tank

Water heater, automatic instantaneous

Capacity at 2 gallons per minute

Capacity at 4 gallons per minute

Capacity at 6 gallons per minute

Water heater, domestic, circulating or
side-arm



35000


50000



142800

285000

428400


35000
Cooking Appliances

Range, freestanding, domestic
Built-in oven or broiler unit, domestic
Built-in top unit, domestic


65000
25000
40000
Other Appliances

Refrigerator

Clothes dryer, Type 1 (domestic)

Gas fireplace direct vent

Gas log

Barbecue

Gaslight


3000

35000

40000

80000

40000

2500
For SI units: 1000 British thermal units per hour = 0.293 kW
Gas piping shall be sized in accordance with one of the following:
  1. Pipe sizing tables or sizing equations in this chapter.
  2. Other approved engineering methods acceptable to the Authority Having Jurisdiction.
  3. Sizing tables included in a listed piping system manufacturer's instructions. [NFPA 54:5.4.3]
The design pressure loss in a piping system under maximum probable now conditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the appliance is greater than or equal to the minimum pressure required by the appliance. [NFPA 54:5.4.4]
Materials used for piping systems shall be in accordance with the requirements of this chapter or shall be acceptable to the Authority Having Jurisdiction. [NFPA 54:5.6.1.1]
Pipe, fittings, valves, or other materials shall not be used again unless they are free of foreign materials and have been ascertained to be approved for the service intended. [NFPA 54:5.6.1.2]
Material not covered by the standards specifications listed herein shall be investigated and tested to determine that it is safe and approved for the proposed service and, in addition, shall be recommended for that service by the manufacturer and shall be acceptable to the Authority Having Jurisdiction. [NFPA 54:5.6.1.3]
Cast-iron pipe shall not be used. [NFPA 54:5.6.2.1]
Steel and wrought-iron pipe shall be not less than standard weight (Schedule 40) and shall comply with one of the following standards:
  1. ASME B36.10
  2. ASTM A53
  3. ASTM A106 [NFPA 54:5.6.2.2]
Copper and copper alloy pipe shall not be used where the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet (scf) of gas (0.7 mg/100 L).

    Threaded copper, copper alloy, or aluminum alloy pipe shall not be used with gases corrosive to such material.
Aluminum alloy pipe shall comply with ASTM B241 (except that the use of alloy 5456 is prohibited) and shall be marked at each end of each length indicating compliance. Aluminum alloy pipe shall be coated to protect against external corrosion where it is in contact with masonry, plaster, insulation, or is subject to repeated wettings by such liquids as water, detergents, or sewage. [NFPA 54:5.6.2.5]

    Aluminum alloy pipe shall not be used in exterior locations or underground. [NFPA 54:5.6.2.6]
Seamless copper, aluminum alloy, or steel tubing shall not be used with gases corrosive to such material. [NFPA 54:5.6.3]
Steel tubing shall comply with ASTM A254. [NFPA 54:5.6.3.1]
Copper and copper alloy tubing shall not be used where the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 scf of gas (0.7 mg/100 L). Copper tubing shall comply with standard Type K or L of ASTM B88 or ASTM B280.
Aluminum alloy tubing shall comply with ASTM B210 or ASTM B241. Aluminum alloy tubing shall be coated to protect against external corrosion where it is in contact with masonry, plaster, insulation, or is subject to repeated wettings by such liquids as water, detergent, or sewage. Aluminum alloy tubing shall not be used in exterior locations or underground. [NFPA 54:5.6.3.3]
Corrugated stainless steel tubing shall be listed in accordance with CSA LC-1. [NFPA 54:5.6.3.4]
Polyethylene plastic pipe, tubing, and fittings used to supply fuel gas shall be in accordance with ASTM D2513. Pipe to be used shall be marked "gas" and "ASTM D2513." [NFPA 54:5.6.4.1.1]
Plastic pipe and fittings used to connect regulator vents to remote vent terminations shall be PVC in accordance with UL 651. PVC vent piping shall not be installed indoors. [NFPA 54:5.6.4.2]
Anodeless risers shall comply with Section 1308.5.4.2.1 through Section 1308.5.4.2.3. [NFPA 54:5.6.4.3]
Factory-assembled anodeless risers shall be recommended by the manufacturer for the gas used and shall be leak-tested by the manufacturer in accordance with written procedures. [NFPA 54:5.6.4.3(1)]
Service head adapters and field assembled anodeless risers incorporating service head adapters shall be recommended by the manufacturer for the gas used and shall be design-certified to be in accordance with the requirements of Category I of ASTM D2513. The manufacturer shall provide the user qualified installation instructions. [NFPA 54:5.6.4.3(2)]
The use of plastic pipe, tubing, and fittings in undiluted liquefied petroleum gas piping systems shall be in accordance with NFPA 58. [NFPA 54:5.6.4.3(3)]
Gas pipe, tubing, and fittings shall be clear and free from cutting burrs and defects in structure or threading, and shall be thoroughly brushed and chip and scale blown. Defects in pipe, tubing, and fittings shall not be repaired. Defective pipe, tubing, and fittings shall be replaced. [NFPA 54:5.6.5]
Where in contact with material or atmosphere exerting a corrosive action, metallic piping and fittings coated with a corrosion-resistant material shall be used. External or internal coatings or linings used on piping or components shall not be considered as adding strength. [NFPA 54:5.6.6]
Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME B1.20.1. [NFPA 54:5.6.7.1]
Pipe with threads that are stripped, chipped, corroded, or otherwise damaged shall not be used. Where a weld opens during the operation of cutting or threading, that portion of the pipe shall not be used. [NFPA 54:5.6.7.2]
Field threading of metallic pipe shall be in accordance with Table 1308.5.7.2. [NFPA 54:5.6.7.3]

TABLE 1308.5.7.2
SPECIFICATIONS FOR THREADING METALLIC PIPE
[NFPA 54: TABLE 5.6.7.3]
IRON PIPE
SIZE
(inches)
APPROXIMATE LENGTH
OF THREADED
PORTION (inches)
APPROXIMATE
NUMBER OF THREADS
TO BE CUT
12 34 10
34 34 10
1 78 10
114 1 11
112 1 11
2 1 11
212 112 12
3 112 12
4 158 13
For SI units: 1 inch = 25.4 mm
Thread joint compounds shall be resistant to the action of liquefied petroleum gas or to other chemical constituents of the gases to be conducted through the piping. [NFPA 54:5.6.7.4]
The type of piping joint used shall be approved for the pressure-temperature conditions and shall be selected giving consideration to joint tightness and mechanical strength under the service conditions. The joint shall be able to sustain the maximum end force due to the internal pressure and additional forces due to temperature expansion or contraction, vibration, fatigue, or the weight of the pipe and its contents. [NFPA 54:5.6.8]
Pipe joints shall be threaded, flanged, brazed, welded, or press-connect fittings made in accordance with CSA LC-4. Where nonferrous pipe is brazed, the brazing materials shall have a melting point in excess of 1000°F (538°C). Brazing alloys shall not contain more than 0.05 percent phosphorus.
Tubing joints shall either be made with approved gas tubing fittings, be brazed with a material having a melting point in excess of 1000°F (538°C), or made by press-connect fittings in accordance with CSA LC-4. Brazing alloys shall not contain more than 0.05 percent phosphorus. [NFPA 54:5.6.8.2]
Flared joints shall be used in systems constructed from nonferrous pipe and tubing where experience or tests have demonstrated that the joint is approved for the conditions and where provisions are made in the design to prevent separation of the joints. [NFPA 54:5.6.8.3]
Metallic pipe fittings shall comply with the following:
  1. Threaded fittings in sizes exceeding 4 inches (100 mm) shall not be used unless acceptable to the Authority Having Jurisdiction.
  2. Fittings used with steel or wrought-iron pipe shall be steel, copper alloy, bronze, malleable iron, or cast-iron.
  3. Fittings used with copper or copper alloy pipe shall be copper, or copper alloy.
  4. Fittings used with aluminum alloy pipe shall be of aluminum alloy.
  5. Cast-iron fittings shall comply with the following:

    1. Flanges shall be permitted.
    2. Bushings shall not be used.
    3. Fittings shall not be used in systems containing flammable gas-air mixtures.
    4. Fittings in sizes 4 inches (100 mm) and larger shall not be used indoors unless approved by the Authority Having Jurisdiction.
    5. Fittings in sizes 6 inches (150 mm) and larger shall not be used unless approved by the Authority Having Jurisdiction.
  6. Aluminum alloy fitting threads shall not form the joint seal.
  7. Zinc-aluminum alloy fittings shall not be used in systems containing flammable gas-air mixtures.
  8. Special fittings such as couplings; proprietary-type joints; saddle tees; gland-type compression fittings; and flared, flareless, or compression-type tubing fittings shall be as follows:

    1. Used within the fitting manufacturer's pressure-temperature recommendations.
    2. Used within the service conditions anticipated with respect to vibration, fatigue, thermal expansion, or contraction.
    3. Installed or braced to prevent separation of the joint by gas pressure or external physical damage.
    4. Acceptable to the Authority Having Jurisdiction.
Plastic pipe, tubing, and fittings shall be installed in accordance with the manufacturer's installation instructions. Section 1308.5.9.1 through Section 1308.5.9.4 shall be observed where making such joints. [NFPA 54:5.6.9]
The joint shall be designed and installed so that the longitudinal pullout resistance of the joint shall be equal to the tensile strength of the plastic piping material. [NFPA 54:5.6.9(1)]
Heat-fusion joints shall be made in accordance with qualified procedures that have been established and proven by test to produce gastight joints as strong as the pipe or tubing being joined. Joints shall be made with the joining method recommended by the pipe manufacturer. Heat-fusion fittings shall be marked "ASTM D2513." [NFPA 54:5.6.9(2)]
Where compression-type mechanical joints are used, the gasket material in the fitting shall be compatible with the plastic piping and with the gas distributed by the system. An internal tubular rigid stiffener shall be used in conjunction with the fitting. The stiffener shall be flush with the end of the pipe or tubing and shall extend not less than the outside end of the compression fitting where installed. The stiffener shall be free of rough or sharp edges and shall not be a forced fit in the plastic. Split tubular stiffeners shall not be used. [NFPA 54:5.6.9(3)]
Plastic piping joints and fittings for use in liquefied petroleum gas-piping systems shall be in accordance with NFPA 58. [NFPA 54:5.6.9(4)]
Flanges shall comply with ASME B16.1, ASME B16.20, or MSS SP-6. The pressure-temperature ratings shall equal or exceed that required by the application. [NFPA 54:5.6.10]
Standard facings shall be permitted for use under this code. Where 150 psi (1034 kPa) steel flanges are bolted to Class 125 castiron flanges, the raised face on the steel flange shall be removed. [NFPA 54:5.6.10.1]
Lapped flanges shall be used aboveground or in exposed locations accessible for inspection. [NFPA 54:5.6.10.2]
The material for gaskets shall be capable of withstanding the design temperature and pressure of the piping system and the chemical constituents of the gas being conducted without change to its chemical and physical properties. The effects of fire exposure to the joint shall be considered in choosing the material. [NFPA 54:5.6.11] Flange gaskets shall comply with the following requirements:
  1. Acceptable materials include the following:

    1. Metal (plain or corrugated)
    2. Composition
    3. Aluminum a-rings and spiral-wound metal gaskets [NFPA 54:5.6.11.1]
  2. Where a flanged joint is opened, the gasket shall be replaced. [NFPA 54:5.6.11.2]
  3. Full-face gaskets shall be used with bronze and castiron flanges. [NFPA 54:5.6.11.3]
Gas meters shall be selected for the maximum expected pressure and permissible pressure drop. [NFPA 54:5.7.1]
Gas meters shall be located in ventilated spaces readily accessible for examination, reading, replacement, or necessary maintenance. [NFPA 54:5.7.2.1]
Gas meters shall not be placed where they will be subjected to damage, such as adjacent to a driveway; under a fire escape; in public passages, halls, or coal bins, or where they will be subject to excessive corrosion or vibration. [NFPA 54:5.7.2.2]
Gas meters shall not be located where they will be subjected to extreme temperatures or sudden extreme changes in temperature. Meters shall not be located in areas where they are subjected to temperatures beyond those recommended by the manufacturer. [NFPA 54:5.7.2.3]
Gas meters shall be supported or connected to rigid piping so as not to exert a strain on the meters. Where flexible connectors are used to connect a gas meter to downstream piping at mobile homes in mobile home parks, the meter shall be supported by a post or bracket placed in a firm footing or by other means providing equivalent support. [NFPA 54:5.7.3]
Meters shall be protected against overpressure, backpressure, and vacuum. [NFPA 54:5.7.4]
Gas piping at multiple meter installations shall be marked by a metal tag or other permanent means attached by the installing agency, designating the building or the part of the building being supplied. [NFPA 54:5.7.5]
A line pressure regulator or gas appliance pressure regulator, as applicable, shall be installed where the gas supply pressure exceeds that at which the branch supply line or appliances are designed to operate or vary beyond design pressure limits. [NFPA 54:5.8.1]
Where the gas supply design pressure in piping systems located indoors exceeds 2 psi (14 kPa) and line pressure regulators are installed to reduce the supply pressure to 14 inches water column (3.5 kPa) or less, the following shall apply:
  1. Regulators shall be provided with factory installed overpressure protection devices.
  2. Overpressure protection devices shall limit the pressure downstream of the line pressure regulator to 2 psi (14 kPa) in the event of failure of the line pressure regulator. [NFPA 54:5.8.3]
Line pressure regulators shall be listed in accordance with CSA Z21.80. [NFPA 54:5.8.2]
The gas pressure regulator shall be accessible for servicing. [NFPA 54:5.8.4]
Pressure regulators shall be protected against physical damage. [NFPA 54:5.8.5]
Line pressure regulators shall comply with the following:
  1. An independent vent to the exterior of the building, sized in accordance with the regulator manufacturer's instructions, shall be provided where the location of a regulator is such that a ruptured diaphragm will cause a hazard. Where more than one regulator is at a location, each regulator shall have a separate vent to the outdoors, or where approved by the Authority Having Jurisdiction, the vent lines shall be permitted to be manifolded in accordance with accepted engineering practices to minimize backpressure in the event of diaphragm failure. Materials for vent piping shall comply with Section 1308.5.

    Exception: A regulator and vent limiting means combination listed in accordance with CSA Z21.80 shall be permitted to be used without a vent to the outdoors.
  2. The vent shall be designed to prevent the entry of water, insects, or other foreign materials that will cause blockage.
  3. The regulator vent shall terminate not less than 3 feet (914 mm) from a source of ignition.
  4. At locations where regulators will be submerged during floods, a special anti flood-type breather vent fitting shall be installed, or the vent line shall be extended above the height of the expected flood waters.
  5. A regulator shall not be vented to the appliance flue or exhaust system. [NFPA 54:5.8.6.1]
Venting of gas appliance pressure regulators shall be in accordance with Section 1310.0. [NFPA 54:5.8.6.2]
The discharge of vents shall be in accordance with the following:
  1. The discharge stacks, vents, or outlet parts of pressure-relieving and pressure-limiting devices shall be located so that gas is safely discharged to the outdoors.
  2. Discharge stacks or vents shall be designed to prevent the entry of water, insects, or other foreign material that could cause blockage. The discharge stack or vent line shall be not less than the same size as the outlet of the pressure-relieving device. [NFPA 54:5.9.7]
Valved and regulated bypasses shall be permitted to be placed around gas line pressure regulators where continuity of service is imperative. [NFPA 54:5.8.7]
Line pressure regulators at multiple regulator installations shall be marked by a metal tag or other permanent means designating the building or the part of the building being supplied. [NFPA 54:5.8.8]
Protective devices shall be installed as close to the equipment as practical where the design of the equipment connected is such that air, oxygen, or standby gases are capable of being forced into the gas supply system. Gas and air combustion mixers incorporating double diaphragm "zero" or "atmosphere" governors or regulators shall require no further protection unless connected directly to compressed air or oxygen at pressures of 5 psi (34 kPa) or more. [NFPA 54:5.10.1]
Protective devices shall include, but not be limited to the following:
  1. Check valves.
  2. Three-way valves (of the type that completely closes one side before starting to open the other side).
  3. Reverse flow indicators controlling positive shutoff valves.
  4. Normally closed air-actuated positive shutoff pressure regulators. [NFPA 54:5.10.2]
A protective device shall be installed between the meter and the appliance or equipment where the operation of the appliance or equipment is such that it is capable of producing a vacuum or a dangerous reduction in gas pressure at the meter. Such protective devices include, but are not limited to, mechanical, diaphragm-operated, or electrically operated low-pressure shutoff valves. [NFPA 54:5.11]
Shutoff valves shall be approved and shall be selected giving consideration to pressure drop, service involved, emergency use, and reliability of operation. Shutoff valves of size 1 inch (25 mm) National Pipe Thread and smaller shall be listed. [NFPA 54:5.12]
Piping systems shall be designed to prevent failure from thermal expansion or contraction. [NFPA 54:5.14.1]
Where local conditions include earthquake, tornado, unstable ground, or flood hazards, special consideration shall be given to increased strength and flexibility of piping supports and connections. [NFPA 54:5.14.2]
Where automatic excess flow valves are installed, they shall be listed, sized, and installed in accordance with the manufacturer's installation instructions. [NFPA 54:5.13]
Venting of gas appliance pressure regulators shall be in accordance with the following requirements:
  1. Appliance pressure regulators requiring access to the atmosphere for successful operation shall be equipped with vent piping leading outdoors or, where the regulator vent is an integral part of the appliance, into the combustion chamber adjacent to a continuous pilot, unless constructed or equipped with a vent limiting means to limit the escape of gas from the vent opening in the event of diaphragm failure.
  2. Vent limiting means shall be employed on listed appliance pressure regulators.
  3. In the case of vents leading outdoors, means shall be employed to prevent water from entering this piping and also to prevent blockage of vents by insects and foreign matter.
  4. Under no circumstances shall a regulator be vented to the appliance flue or exhaust system.
  5. In the case of vents entering the combustion chamber, the vent shall be located so the escaping gas will be readily ignited by the pilot and the heat liberated thereby will not adversely affect the normal operation of the safety shutoff system. The terminus of the vent shall be securely held in a fixed position relative to the pilot. For manufactured gas, the need for a flame arrester in the vent piping shall be determined.
  6. Vent lines from an appliance pressure regulator and bleed lines from a diaphragm-type valve shall not be connected to a common manifold terminating in a combustion chamber. Vent lines shall not terminate in positive-pressure-type combustion chambers. [NFPA 54:9.1.19]
Underground gas piping shall be installed with approved clearance from other underground structures to avoid contact therewith, to allow maintenance, and to protect against damage from proximity to other structures, In addition, underground plastic piping shall be installed with approved clearance or shall be insulated from sources of heat so as to prevent the heat from impairing the serviceability of the pipe, [NFPA 54:7.1.1]
Underground piping systems shall be installed with a cover not less than 12 inches (305 mm), Where external damage to the pipe or tubing from external forces is likely to result, the cover shall be not less than 18 inches (457 mm). Where a cover not less than 12 inches (305 mm) cannot be provided, the pipe shall be installed in conduit or bridged (shielded). [NFPA 54:7.1.2.1]
The trench shall be graded so that the pipe has a firm, substantially continuous bearing on the bottom of the trench. [NFPA 54:7.1.2.2]
Where flooding of the trench is done to consolidate the backfill, care shall be exercised to see that the pipe is not floated from its firm bearing on the trench bottom. [NFPA 54:7.1.2.3]
Gas piping in contact with earth or other material that is capable of corroding the piping shall be protected against corrosion in an approved manner. Where dissimilar metals are joined underground, an insulating coupling or fitting shall be used. Piping shall not be laid in contact with cinders, Uncoated threaded or socket-welded joints shall not be used in piping in contact with soil or where internal or external crevice corrosion is known to occur. [NFPA 54:7.1.3]
Where the formation of hydrates or ice is known to occur, piping shall be protected against freezing. [NFPA 54:7.1.4]
Underground piping installed through the outer foundation or basement wall of a building shall be encased in a protective sleeve or protected by an approved device or method. The space between the gas piping and the sleeve and between the sleeve and the wall shall be sealed to prevent entry of gas and water. [NFPA 54:7.1.5]
Where gas piping is installed underground beneath buildings, the piping shall be one of the following:
  1. Encased in an approved conduit designed to withstand the imposed loads and installed in accordance with Section 1311.1.6.1 or Section 1311.1.6.2.
  2. A piping or encasement system listed for installation beneath buildings. [NFPA 54:7.1.6]
The conduit shall extend into an accessible portion of the building and, at the point where the conduit terminates in the building, the space between the conduit and the gas piping shall be scaled to prevent the possible entrance of a gas leakage, Where the end sealing is of a type that will retain the full pressure of the pipe, the conduit shall be designed for the same pressure as the pipe, The conduit shall extend not less than 4 inches (102 mm) outside the building, be vented outdoors above finished ground level, and be installed so as to prevent the entrance of water and insects, [NFPA 54:7.1.6.1]
Where the conduit originates and terminates within the same building, the conduit shall originate and terminate in an accessible portion of the building and shall not be sealed. [NFPA 54:7.1.6.2]
Plastic piping shall be installed outdoors, underground only.

Exceptions:
  1. Plastic piping shall be permitted to terminate aboveground where an anodeless riser is used.
  2. Plastic piping shall be permitted to terminate with a wall head adapter aboveground in buildings, including basements, where the plastic piping is inserted in a piping material permitted for use in buildings. [NFPA 54:7.1.7.1]
Connections made between metallic and plastic piping shall be made with fittings that are in accordance with one of the following:
  1. ASTM D2513
  2. ASTM F1973
  3. ASTM F2509 [NFPA 54:7.1.7.2]
An electrically continuous corrosion-resistant tracer wire (not less than AWG 14) or tape shall be buried with the plastic pipe to facilitate locating. One end of the tracer wire or tape shall be brought aboveground at a building wall or riser. [NFPA 54:7.1.7.3]
Piping installed aboveground shall be securely supported and located where it will be protected from physical damage, Where passing through an exterior wall, the piping shall also be protected against corrosion by coating or wrapping with an inert material approved for such applications, The piping shall be sealed around its circumference at the point of the exterior penetration to prevent the entry of water, insects, and rodents, Where piping is encased in a protective pipe sleeve, the annular spaces between the gas piping and the sleeve and between the sleeve and the wall opening shall be sealed. [NFPA 54:7.2.1]
The installation of gas piping shall not cause structural stresses within building components to exceed allowable design limits. Approval shall be obtained before beams or joists are cut or notched. [NFPA 54:7.2.2]
Piping for other than dry gas conditions shall be sloped not less than 14 inch in 15 feet (1.4 mm/m) to prevent traps. [NFPA 54:7.2.3]
Gas piping shall be permitted to be installed in accessible spaces between a fixed ceiling and a dropped ceiling, whether or not such spaces are used as a plenum. Valves shall not be located in such spaces.

Exception: Appliance or equipment shutoff valves required by this code shall be permitted to be installed in accessible spaces containing vented appliances.
Gas piping inside a building shall not be installed in or through a clothes chute, chimney or gas vent, dumbwaiter, elevator shaft, or air duct, other than combustion air ducts. [NFPA 54:7.2.4]

Exception: Ducts used to provide ventilation air in accordance with Section 701.0 or to above-ceiling spaces in accordance with Section 1311.2.2.1.
Piping shall be supported with metal pipe hooks, metal pipe straps, metal bands, metal brackets, metal hangers, or building structural components; approved for the size of piping; of adequate strength and quality and located at intervals so as to prevent or damp out excessive vibration. Piping shall be anchored to prevent undue strains on connected appliances and equipment and shall not be supported by other piping. Pipe hangers and supports shall comply with the requirements of MSS SP-58. [NFPA 54:7.2.5.1]
Spacing of supports in gas piping installations shall not exceed the distance shown in Table 1311.2.4.1. Spacing of supports for CSST shall be in accordance with the CSST manufacturer's instruction. [NFPA 54:7.2.5.2]

TABLE 1311.2.4.1
SUPPORT OF PIPING
[NFPA 54: TABLE 7.2.5.2]
STEEL PIPE,
NOMINAL SIZE
OF PIPE
(inches)
SPACING OF
SUPPORTS
(feet)
NOMINAL SIZE
OF TUBING
SMOOTH-WALL
(inches O.D.)
SPACING OF
SUPPORTS
(feet)
12 6 12 4
34 or 1 8 58 or 34 6
114 or larger
(horizontal)
10 78 or 1
(horizontal)
8
114 or larger
(vertical)
Every floor
level
1 or larger
(vertical)
Every floor
level
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm
Supports, hangers, and anchors shall be installed so as not to interfere with the free expansion and contraction of the piping between anchors. Parts of the supporting system shall be designed and installed so they are not disengaged by movement of the supported piping. [NFPA 54:7.2.5.3]
Where piping containing gas is to be removed, the line shall be first disconnected from sources of gas and then thoroughly purged with air, water, or inert gas before cutting or welding is done. [NFPA 54:7.2.6]
Gas piping in concealed locations shall be installed in accordance with this section. [NFPA 54:7.3.1]
Where gas piping is to be concealed, connections shall be of the following type:
  1. Pipe fittings, such as elbows, tees, couplings, and right/left nipple/couplings.
  2. Joining tubing by brazing (see Section 1308.5.8.2).
  3. Fittings listed for use in concealed spaces or that have been demonstrated to sustain, without leakage, forces due to temperature expansion or contraction, vibration, or fatigue based on their geographic location, application, or operation.
  4. Where necessary to insert fittings in gas pipe that has been installed in a concealed location, the pipe shall be reconnected by welding, flanges, or the use of a right/left nipple/coupling.
Concealed gas piping shall not be located in solid partitions. [NFPA 54:7.3.3]
This provision shall not apply to tubing that pierces walls, floors, or partitions. Tubing installed vertically and horizontally inside hollow walls or partitions without protection along its entire concealed length shall be in accordance with the following requirements:
  1. A steel striker barrier not less than 0.0508 of an inch (1.3 mm) thick, or equivalent, shall be installed between the tubing and the finished wall and extend not less than 4 inches (102 mm) beyond concealed penetrations of plates, firestops, wall studs, and similar construction features.
  2. The tubing shall be installed in single runs and shall not be rigidly secured. [NFPA 54:7.3.4]
In industrial occupancies, gas piping in solid floors such as concrete shall be laid in channels in the floor and covered to permit access to the piping with minimum damage to the building. Where piping in floor channels is exposed to excessive moisture or corrosive substances, the piping shall be protected in an approved manner. [NFPA 54:7.3.5.1]

Exception: In other than industrial occupancies and where approved by the Authority Having Jurisdiction, gas piping embedded in concrete floor slabs constructed with portland cement shall be surrounded with not less than 112 inches (38 mm) of concrete and shall not be in physical contact with other metallic structures such as reinforcing rods or electrically neutral conductors. Piping, fittings, and risers shall be protected against corrosion in accordance with Section 1308.5.6. Piping shall not be embedded in concrete slabs containing quick-set additives or cinder aggregate. [NFPA 54:7.3.5.2]
Where gas piping exceeding 5 psi (34 kPa) is located within vertical chases in accordance with Section 1311.5(2), the requirements of Section 1311.4.1 through Section 1311.4.3 shall apply. [NFPA 54:7.4]
Where pressure reduction is required in branch connections in accordance with Section 1311.5, such reduction shall take place either inside the chase or immediately adjacent to the outside wall of the chase. Regulator venting and downstream overpressure protection shall comply with Section 1308.7.1 and Section 1308.7.5. The regulator shall be accessible for service and repair, and vented in accordance with one of the following:
  1. Where the fuel gas is lighter than air, regulators equipped with a vent limiting means shall be permitted to be vented into the chase. Regulators not equipped with a vent limiting means shall be permitted to be vented either directly to the outdoors or to a point within the top 1 foot (305 mm) of the chase.
  2. Where the fuel gas is heavier than air, the regulator vent shall be vented directly to the outdoors. [NFPA 54:7.4.1]
Chase construction shall comply with local building codes with respect to fire resistance and protection of horizontal and vertical openings. [NFPA 54:7.4.2]
A chase shall be ventilated to the outdoors and at the top. The opening(s) shall have a minimum free area [in square inches (m2)] equal to the product of one-half of the maximum pressure in the piping [in psi (kPa)] times the largest nominal diameter of that piping [in inches (mm)], or the cross-sectional area of the chase, whichever is smaller. Where more than one fuel gas piping system is present, the free area for each system shall be calculated and the largest area used. [NFPA 54:7.4.3]
The maximum design operating pressure for piping systems located inside buildings shall not exceed 5 psi (34 kPa) unless one or more of the following conditions are met:
  1. The piping system is welded.
  2. The piping is located in a ventilated chase or otherwise enclosed for protection against accidental gas accumulation.
  3. The piping is located inside buildings or separate areas of buildings used exclusively for one of the following:

    1. Industrial processing or heating
    2. Research
    3. Warehousing
    4. Boiler or mechanical equipment rooms
  4. The piping is a temporary installation for building under construction.
  5. The piping serves appliances or equipment used for agricultural purposes.
  6. The piping system is an LP-Gas piping system with a design operating pressure exceeding 20 psi (138 kPa) and in accordance with NFPA 58. LP-Gas systems designed to operate below -5°F (-21°C) or with butane or a propane-butane mix shall be designed to either accommodate liquid LP-Gas or to prevent LP-Gas vapor from condensing back into liquid. [NFPA 54:5.5]
The maximum operating pressure for piping systems serving appliances designed to operate at 14 inches water column (3.5 kPa) inlet pressure or less shall be 2 pounds-force per square inch gauge (psig) (14 kPa) unless an overpressure protection device designed to limit pressure at the appliance to 2 psig (14 kPa) upon failure of the line gas pressure regulator is installed.
Changes in direction of gas pipe shall be made by the use of fittings, factory bends, or field bends. [NFPA 54:7.5]
Metallic pipe bends shall comply with the following:
  1. Bends shall be made with bending equipment and procedures intended for that purpose.
  2. Bends shall be smooth and free from buckling, cracks, or other evidence of mechanical damage.
  3. The longitudinal weld of the pipe shall be near the neutral axis of the bend.
  4. The pipe shall not be bent through an arc of more than 90 degrees (1.57 rad).
  5. The inside radius of a bend shall be not less than six times the outside diameter of the pipe. [NFPA 54:7.5.1]
Plastic pipe bends shall comply with the following:
  1. The pipe shall not be damaged, and the internal diameter of the pipe shall not be effectively reduced.
  2. Joints shall not be located in pipe bends.
  3. The radius of the inner curve of such bends shall be not less than 25 times the inside diameter of the pipe.
  4. Where the piping manufacturer specifies the use of special bending equipment or procedures, such equipment or procedures shall be used. [NFPA 54:7.5.2]
Factory-made welding elbows or transverse segments cut therefrom shall have an arc length measured along the crotch of not less than 1 inch (25.4 mm) for pipe sizes 2 inches (50 mm) and larger. [NFPA 54:7.5.3]
For other than dry gas conditions, a drip shall be provided at a point in the line of pipe where condensate is capable of collecting. Where required by the Authority Having Jurisdiction or the serving gas supplier, a drip shall also be provided at the outlet of the meter. This drip shall be so installed as to constitute a trap wherein an accumulation of condensate will shut off the flow of gas before it will run back into the meter. [NFPA 54:7.6.1]
Drips shall be installed in such locations that they will be readily accessible to permit cleaning or emptying. A drip shall not be located where the condensate is likely to freeze. [NFPA 54:7.6.2]
The installation of sediment traps shall comply with Section 1313.7. [NFPA 54:7.6.3]
Outlets shall be located and installed in accordance with the following requirements:
  1. The outlet fittings or piping shall be securely fastened in place.
  2. Outlets shall not be located behind doors.
  3. Outlets shall be located far enough from floors, walls, patios, slabs, and ceilings to permit the use of wrenches without straining, bending, or damaging the piping.
  4. The unthreaded portion of gas piping outlets shall extend not less than 1 inch (25.4 mm) through finished ceilings or indoor or outdoor walls.
  5. The unthreaded portion of gas piping outlets shall extend not less than 2 inches (51 mm) above the surface of floors or outdoor patios or slabs.
  6. The provisions of Section 1311.9(4) and Section 1311.9(5) shall not apply to listed quick-disconnect devices of the flush-mounted type or listed gas convenience outlets. Such devices shall be installed in accordance with the manufacturer's installation instructions. [NFPA 54:7.7.1]
Each outlet, including a valve, shall be closed gastight with a threaded plug or cap immediately after installation and shall be left closed until the appliance or equipment is connected thereto. Where an appliance or equipment is disconnected from an outlet, and the outlet is not to be used again immediately, it shall be capped or plugged gastight.

Exceptions:
  1. Laboratory appliances installed in accordance with Section 1313.2.1 shall be permitted.
  2. The use of a listed quick-disconnect device with integral shutoff or listed gas convenience outlet shall be permitted. [NFPA 54:7.7.2.1]
Appliance shutoff valves installed in fireplaces shall be removed and the piping capped gastight where the fireplace is used for solid-fuel burning. [NFPA 54:7.7.2.2]
Where a branch outlet is placed on a main supply line before it is known what size pipe will be connected to it, the outlet shall be of the same size as the line that supplies it. [NFPA 54:7.8]
An accessible gas shutoff valve shall be provided upstream of each gas pressure regulator. Where two gas pressure regulators are installed in series in a single gas line, a manual valve shall not be required at the second regulator. [NFPA 54:7.9.1]
Main gas shutoff valves controlling several gas piping systems shall be readily accessible for operation and installed so as to be protected from physical damage. They shall be marked with a metal tag or other permanent means attached by the installing agency so that the gas piping systems supplied through them are readily identified. [NFPA 54:7.9.2.1]
In multiple-tenant buildings supplied through a master meter, through one service regulator where a meter is not provided, or where meters or service regulators are not readily accessible from the appliance or equipment location, an individual shutoff valve for each apartment or tenant line shall be provided at a convenient point of general accessibility. In a common system serving a number of individual buildings, shutoff valves shall be installed at each building. [NFPA 54:7.9.2.2]
An exterior shutoff valve to permit turning off the gas supply to each building in an emergency shall be provided. The emergency shutoff valves shall be plainly marked as such and their locations posted as required by the Authority Having Jurisdiction. [NFPA 54:7.9.2.3]
Each laboratory space containing two or more gas outlets installed on tables, benches, or in hoods in educational, research, commercial and industrial occupancies shall have a single shutoff valve through which such gas outlets are supplied. The shutoff valve shall be accessible and shall be located within the laboratory or located adjacent to the laboratory's egress door and shall be identified. [NFPA 54:7.9.2.4]
No device shall be placed inside the gas piping or fittings that will reduce the cross-sectional area or otherwise obstruct the free flow of gas, except where an allowance in the piping system design has been made for such a device and where approved by the Authority Having Jurisdiction. [NFPA 54:7.10]
Where gas-air mixing machines are employed to produce mixtures above or below the flammable range, they shall be provided with stops to prevent adjustment of the mixture to within or approaching the flammable range. [NFPA 54:7.11]
Systems containing flammable gas-air mixtures shall be in accordance with Section 1311.14.1 through Section 1311.14.6.
A central premix system with a flammable mixture in the blower or compressor shall consist of the following components:
  1. Gas-mixing machine in the form of an automatic gas-air proportioning device combined with a downstream blower or compressor.
  2. Flammable mixture piping. not less than Schedule 40 NPS.
  3. Automatic firecheck(s).
  4. Safety blowout(s) or backfire preventers for systems utilizing flammable mixture lines above 212 inches (65 mm) nominal pipe size (NPS) or the equivalent. [NFPA 54:7.12.1]
The following components shall also be permitted to be utilized in a type of central premix system:
  1. Flowmeter(s)
  2. Flame arrester(s) [NFPA 54:7.12.2]
Gas-mixing machines shall have nonsparking blowers and shall be so constructed that a flashback will not rupture machine casings. [NFPA 54:7.12.3]
A mixing blower system shall be limited to applications with minimum practical lengths of mixture piping, limited to a mixture pressure of not more than 10 inches water column (2.5 kPa) and limited to gases containing no more than 10 percent hydrogen.

    The blower shall be equipped with a gas-control valve at its air entrance so arranged that gas is admitted to the airstream, entering the blower in proper proportions for correct combustion by the type of burners employed, the said gas-control valve being of either the zero governor or mechanical ratio valve type that controls the gas and air adjustment simultaneously. No valves or other obstructions shall be installed between the blower discharge and the burner or burners. [NFPA 54:7.12.4]
Installation of gas-mixing machines shall comply with the following:
  1. The machine shall be located in a large, well-ventilated area or in a small detached building or cutoff room provided with room construction and explosion vents in accordance with sound engineering principles. Such rooms or belowgrade installations shall have approved positive ventilation.
  2. Where gas-mixing machines are installed in well-ventilated areas, the type of electrical equipment shall be in accordance with NFPA 70, for general service conditions unless other hazards in the area prevail. Where gas-mixing machines are installed in small detached buildings or cutoff rooms, the electrical equipment and wiring shall be installed in accordance with NFPA 70.
  3. Air intakes for gas-mixing machines using compressors or blowers shall be taken from outdoors where practical.
  4. Controls for gas-mixing machines shall include interlocks and a safety shutoff valve of the manual reset type in the gas supply connection to each machine arranged to automatically shut off the gas supply in the event of high or low gas pressure. Except for open-burner installations, the controls shall be interlocked so that the blower or compressor will stop operating following a gas supply failure. Where a system employs pressurized air, means shall be provided to shut off the gas supply in the event of air failure.
  5. Centrifugal gas-mixing machines in parallel shall be reviewed by the user and equipment manufacturer before installation, and means or plans for minimizing these effects of downstream pulsation and equipment overload shall be prepared and utilized as needed. [NFPA 54:7.12.5]
Automatic firechecks and safety blowouts or backfire preventers shall be provided in piping systems distributing flammable air-gas mixtures from gas-mixing machines to protect the piping and the machines in the event of flashback, in accordance with the following:
  1. Approved automatic firechecks shall be installed upstream as close as practicable to the burner inlets in accordance with the firecheck manufacturer's installation instructions.
  2. A separate manually operated gas valve shall be provided at each automatic firecheck for shutting off the flow of gas-air mixture through the firecheck after a flashback has occurred. The valve shall be located upstream as close as practical to the inlet of the automatic firecheck.

    Caution:

    These valves shall not be reopened after a flashback has occurred until the firecheck has cooled to prevent reignition of the flammable mixture and has been reset properly.
  3. A safety blowout or backfiring preventer shall be provided in the mixture line near the outlet of each gas-mixing machine where the size of the piping is more than 212 inches (65 mm) NPS, or equivalent, to protect the mixing equipment in the event of an explosion passing through an automatic firecheck. The manufacturer's installation instructions shall be followed where installing these devices, particularly after a disc has burst. The discharge from the safety blowout or backfire preventer shall be located or shielded so that particles from the ruptured disc cannot be directed toward personnel. Wherever there are interconnected installations of gas-mixing machines with safety blowouts or backfire preventers, provision shall be made to keep the mixture from other machines from reaching a ruptured disc opening. Check valves shall not be used for this purpose.
  4. Large-capacity premix systems provided with explosion heads (rupture discs) to relieve excessive pressure in pipelines shall be located at and vented to a safe outdoor location. Provisions shall be provided for automatically shutting off the supply of gas-air mixture in the event of rupture. [NFPA 54:7.12.6]
Each aboveground portion of a gas piping system other than CSST that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping, other than CSST, shall be considered to be bonded where it is connected to appliances that are connected to the appliance grounding conductor of the circuit supplying that appliance. [NFPA 54:7.13.1]
CSST gas piping systems shall be bonded to the electrical service grounding electrode system. The bonding jumper shall connect to a metallic pipe or fitting between the point of delivery and the first downstream CSST fitting. The bonding jumper shall be not smaller than 6 AWG copper wire or equivalent. Gas piping systems that contain one or more segments of CSST shall be bonded in accordance with this section. [NFPA 54:7.13.2]
Gas piping shall not be used as a grounding conductor or electrode. [NFPA 54:7.13.3]
Where a lightning protection system is installed, the bonding of the gas piping shall be in accordance with NFPA 780. [NFPA 54:7.13.4]
Electrical circuits shall not utilize gas piping or components as conductors.

Exception: Low-voltage (50v or less) control circuits, ignition circuits, and electronic flame detection device circuits shall be permitted to make use of piping or components as a part of an electric circuit. [NFPA 54:7.14]
Electrical connections between wiring and electrically operated control devices in a piping system shall comply with the requirements of NFPA 70. [NFPA 54:7.15.1]
An essential safety control depending on electric current as the operating medium shall be of a type that will shut off (fail safe) the flow of gas in the event of current failure. [NFPA 54:7.15.2]
Appliances shall be connected to the building piping in accordance with Section 1313.4 through Section 1313.6 by one of the following:
  1. Rigid metallic pipe and fittings.
  2. Semirigid metallic tubing and metallic fittings. Aluminum alloy tubing shall not be used in exterior locations.
  3. A listed connector in accordance with CSA Z21.24. The connector shall be used in accordance with the manufacturer's installation instructions and shall be in the same room as the appliance. One connector shall be used for each appliance.
  4. A listed connector in accordance with CSA Z21.75. One connector shall be used for each appliance.
  5. CSST where installed in accordance with the manufacturer's installation instructions.
  6. Listed nonmetallic gas hose connectors in accordance with Section 1313.2.
  7. In Section 1313.1(2) through Section 1313.1(6), the connector or tubing shall be installed so as to be protected against physical and thermal damage. Aluminum alloy tubing and connectors shall be coated to protect against external corrosion where they are in contact with masonry, plaster, or insulation, or are subject to repeated wettings by such liquids as water (except rainwater), detergents, or sewage. Connectors and tubing shall not be installed through an opening in an appliance housing, cabinet, or casing, unless the tubing or connector is protected against damage. [NFPA 54:9.6.1]
Commercial cooking appliances that are moved for cleaning and sanitation purposes shall be connected in accordance with the connector manufacturer's installation instructions using a listed appliance connector in accordance with CSA Z21.69. The commercial cooking appliance connector installation shall be configured in accordance with the manufacturer's installation instructions. [NFPA 54:9.6.1.1]
Movement of appliances with casters shall be limited by a restraining device installed in accordance with the connector and appliance manufacturer's installation instructions. [NFPA 54:9.6.1.2]
Listed gas hose connectors shall be installed in accordance with the manufacturer's installation instructions and in accordance with Section 1313.2.1 and Section 1313.2.2. [NFPA 54:9.6.2]
Indoor gas hose connectors shall be used to connect laboratory, shop, and ironing appliances or equipment requiring mobility during operation. An appliances or equipment shutoff valve shall be installed where the connector is attached to the building piping. The connector shall be of minimum length and shall not exceed 6 feet (1829 mm). The connector shall not be concealed and shall not extend from one room to another or pass through wall partitions, ceilings, or floors.
Where outdoor gas hose connectors are used to connect portable outdoor appliances, the connector shall be listed in accordance with CSA Z21.54. An appliance shutoff valve, a listed quick-disconnect device, or a listed gas convenience outlet shall be installed where the connector is attached to the supply piping and in such a manner to prevent the accumulation of water or foreign matter. This connection shall be made in the outdoor area where the appliance is to be used. [NFPA 54:9.6.2(2)].

    The connector length shall not exceed 15 feet (4572 mm).
Where portable industrial appliances or appliances requiring mobility or subject to vibration, are connected to the building gas piping system by the use of a flexible hose, the hose shall be approved and safe for the conditions under which it is used. [NFPA 54:9.6.3.1]
Where industrial appliances requiring mobility are connected to the rigid piping by the use of swivel joints or couplings, the swivel joints or couplings shall be approved for the service required, and the minimum number required shall be installed. [NFPA 54:9.6.3.2]
Where industrial appliances subject to vibration are connected to the building piping system by the use of metal flexible connectors, the connectors shall be approved for the service required. [NFPA 54:9.6.3.3]
Where flexible connections are used, they shall be of the minimum practical length and shall not extend from one room to another or pass through walls, partitions, ceilings, or floors. Flexible connections shall not be used in a concealed location. They shall be protected against physical or thermal damage and shall be provided with gas shutoff valves in readily accessible locations in rigid piping upstream from the flexible connections. [NFPA 54:9.6.3.4]
Appliances connected to a piping system shall have an accessible, approved manual shutoff valve with a nondisplaceable valve member, or a listed gas convenience outlet. Appliance shutoff valves and convenience outlets shall serve a single appliance and shall be installed within 6 feet (1829 mm) of the appliance it serves. Where a connector is used, the valve shall be installed upstream of the connector. A union or flanged connection shall be provided downstream from the valve to permit removal of appliance controls. Shutoff valves serving decorative appliances shall be permitted to be installed in fireplaces where listed for such use. [NFPA 54:9.6.4, 9.6.4.1]

Exceptions:
  1. Shutoff valves shall be permitted to be accessibly located inside or under an appliance where such appliance is removed without removal of the shutoff valve.
  2. Shutoff valves shall be permitted to be accessibly located inside wall heaters and wall furnaces listed for recessed installation where necessary maintenance is performed without removal of the shutoff valve.
Quick-disconnect devices used to connect appliances to the building piping shall be listed to CSA Z21.41. Where installed indoors, an approved manual shutoff valve with a nondisplaceable valve member shall be installed upstream of the quick-disconnect device. [NFPA 54:9.6.5]
Appliances shall be permitted to be connected to the building piping by means of a listed gas convenience outlet, in conjunction with a listed appliance connector, installed in accordance with the manufacturer's installation instructions.

    Gas convenience outlets shall be listed in accordance with CSA Z21.90 and installed in accordance with the manufacturer's installation instructions. [NFPA 54:9.6.6]
Where a sediment trap is not incorporated as a part of the appliance, a sediment trap shall be installed downstream of the appliance shutoff valve as close to the inlet of the appliance as practical, but before the flex connector, where used at the time of appliance installation. The sediment trap shall be either a tee fitting with a capped nipple in the bottom outlet, as illustrated in Figure 1313.7 or other device recognized as an effective sediment trap. Illuminating appliances, ranges, clothes dryers, decorative appliances for installation in vented fireplaces, gas fireplaces, and outdoor grills shall not be required to be so equipped.


For SI units: 1 inch = 25.4 mm
FIGURE 1313.7
METHOD OF INSTALLING A TEE FITTING
SEDIMENT TRAP
[NFPA 54: FIGURE 9.6.7]
Piping shall be installed in a manner not to interfere with inspection, maintenance, or servicing of the appliance. [NFPA 54:9.6.8]
Liquefied petroleum gas facilities shall comply with NFPA 58.
Unlisted appliances for use with undiluted liquefied petroleum gases and installed indoors, except attended laboratory equipment, shall be equipped with safety shutoff devices of the complete shutoff type. [NFPA 54:9.1.4]
Prior to acceptance and initial operation, piping installations shall be visually inspected and pressure-tested to determine that the materials, design, fabrication, and installation practices are in accordance with the requirements of this code. [NFPA 54:8.1.1.1]
Inspection shall consist of visual examination during or after manufacture, fabrication, assembly, or pressure tests. [NFPA 54:8.1.1.2]
Where repairs or additions are made following the pressure test, the affected piping shall be tested. Minor repairs and additions are not required to be pressure-tested provided that the work is inspected and connections are tested with a noncorrosive leak-detecting fluid or other leak-detecting methods approved by the Authority Having Jurisdiction. [NFPA 54:8.1.1.3]
Where new branches are installed to new appliances, the newly installed branches shall be required to be pressure-tested. Connections between the new piping and the existing piping shall be tested with a noncorrosive leak-detecting fluid or approved leak-detecting methods. [NFPA 54:8.1.1.4]
A piping system shall be tested as a complete unit or in sections. Under no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and test medium in an adjacent section, unless two valves are installed in series with a valved "telltale" located between these valves. A valve shall not be subjected to the test pressure unless it is determined that the valve, including the valve-closing mechanism, is designed to safely withstand the pressure. [NFPA 54:8.1.1.5]
Regulator and valve assemblies fabricated independently of the piping system in which they are to be installed shall be permitted to be tested with inert gas or air at the time of fabrication. [NFPA 54:8.1.1.6]
The test medium shall be air, nitrogen, carbon dioxide, or an inert gas. OXYGEN SHALL NEVER BE USED. [NFPA 54:8.1.2]
Test preparation shall comply with Section 1314.2.1 through Section 1314.2.6.
Pipe joints, including welds, shall be left exposed for examination during the test.

Exception: Covered or concealed pipe end joints that have been previously tested in accordance with this code. [NFPA 54:8.1.3.1]
Expansion joints shall be provided with temporary restraints, where required, for the additional thrust load under test. [NFPA 54:8.1.3.2]
Appliances and equipment that are not to be included in the test shall be either disconnected from the piping or isolated by blanks, blind flanges, or caps. Flanged joints at which blinds are inserted to blank off other equipment during the test shall not be required to be tested. [NFPA 54:8.1.3.3]
Where the piping system is connected to appliances or equipment designed for operating pressures of less than the test pressure, such appliances or equipment shall be isolated from the piping system by disconnecting them and capping the outlets. [NFPA 54:8.1.3.4]
Where the piping system is connected to appliances or equipment designed for operating pressures equal to or greater than the test pressure, such appliances and equipment shall be isolated from the piping system by closing the individual appliance shutoff valve(s). [NFPA 54:8.1.3.5]
Testing of piping systems shall be performed in a manner that protects the safety of employees and the public during the test. [NFPA 54:8.1.3.6]
This inspection shall include an air, CO2, or nitrogen pressure test, at which time the gas piping shall stand a pressure of not less than 10 psi (69 kPa) gauge pressure. Test pressures shall be held for a length of time satisfactory to the Authority Having Jurisdiction but in no case less than 15 minutes with no perceptible drop in pressure. For welded piping, and for piping carrying gas at pressures in excess of 14 inches water column (3.5 kPa) pressure, the test pressure shall be not less than 60 psi (414 kPa) and shall be continued for a length of time satisfactory to the Authority Having Jurisdiction, but in no case for less than 30 minutes. For CSST carrying gas at pressures in excess of 14 inches water column (3.5 kPa) pressure, the test pressure shall be 30 psi (207 kPa) for 30 minutes. These tests shall be made using air, CO2, or nitrogen pressure and shall be made in the presence of the Authority Having Jurisdiction. Necessary apparatus for conducting tests shall be furnished by the permit holder. Test gauges used in conducting test shall be in accordance with Section 1303.3.3.1 through Section 1303.3.3.4.
The piping system shall withstand the test pressure specified without showing evidence of leakage or other defects. Reduction of test pressures as indicated by pressure gauges shall be deemed to indicate the presence of a leak unless such reduction is readily attributed to some other cause. [NFPA 54:8.1.5.1]
The leakage shall be located by means of an approved gas detector, a noncorrosive leak detection fluid, or other approved leak detection methods. Matches, candles, open flames, or other methods that provide a source of ignition shall not be used. [NFPA 54:8.1.5.2]
Where leakage or other defects are located, the affected portion of the piping system shall be repaired or replaced and retested. [NFPA 54:8.1.5.3]
Leak checks using fuel gas shall be permitted in piping systems that have been pressure-tested in accordance with Section 1314.0. [NFPA 54:8.2.1]
During the process of turning gas on into a system of new gas piping, the entire system shall be inspected to determine that there are no open fittings or ends and that valves at unused outlets are closed and plugged or capped. [NFPA 54:8.2.2]
Immediately after the gas is turned on into a new system or into a system that has been initially restored after an interruption of service, the piping system shall be checked for leakage. Where leakage is indicated, the gas supply shall be shut off until the necessary repairs have been made. [NFPA 54:8.2.3]
Appliances and equipment shall not be placed in operation until after the piping system has been checked in accordance with Section 1314.5.2; connections to the appliance are checked for leakage; and purged in accordance with Section 1314.6. [NFPA 54:8.2.4]
The purging of piping shall be in accordance with Section 1314.6.1 through Section 1314.6.3. [NFPA 54:8.3]
The purging of piping systems shall be in accordance with the provisions of Section 1314.6.1.1 through Section 1314.6.1.4 where the piping system meets either of the following:
  1. The design operating gas pressure exceeds 2 psig (14 kPa).
  2. The piping being purged contains one or more sections of pipe or tubing meeting the size and length criteria of Table 1314.6.1. [NFPA 54:8.3.1]
TABLE 1314.6.1
SIZE AND LENGTH OF PIPING
[NFPA 54: TABLE 8.3.1]*
NOMINAL PIPING SIZE
(inches)
LENGTH OF PIPING
(feet)
≥ 212 < 3 > 50
≥ 3 < 4 > 30
≥ 4 < 6 > 15
≥ 6 < 8 > 10
≥8 Any length
For Sl units: 1 inch = 25 mm; 1 foot 304.8 mm
* (SST EHD size of 62 is equivalent (0 nominal 2 inches (50 mm) pipe or Tubing size.
Where existing gas piping is opened, the section that is opened shall be isolated from the gas supply and the line pressure vented in accordance with Section 1314.6.1.3. Where gas piping meeting the criteria of Table 1314.6.1 is removed from service, the residual fuel gas in the piping shall be displaced with an inert gas. [NFPA 54:8.3.1.1]
Where gas piping containing air and meeting the criteria of Table 1314.6.1 is placed in operation, the air in the piping shall first be displaced with an inert gas. The inert gas shall then be displaced with fuel gas in accordance with Section 1314.6.1.3. [NFPA 54:8.3.1.2]
The open end of a piping system being pressure vented or purged shall discharge directly to an outdoor location. Purging operations shall comply with the following requirements:
  1. The point of discharge shall be controlled with a shutoff valve.
  2. The point of discharge shall be located not less than 10 feet (3048 mm) from sources of ignition, not less than 10 feet (3048 mm) from building openings, and not less than 25 feet (7620 mm) from mechanical air intake openings.
  3. During discharge, the open point of discharge shall be continuously attended and monitored with a combustible gas indicator that is in accordance with Section 1314.6.1.4.
  4. Purging operations introducing fuel gas shall be stopped where 90 percent fuel gas by volume is detected within the pipe.
  5. Persons not involved in the purging operations shall be evacuated from areas within 10 feet (3048 mm) of the point of discharge. [NFPA 54:8.3.1.3]
Combustible gas indicators shall be listed and shall be calibrated in accordance with the manufacturer's instructions. Combustible gas indicators shall numerically display a volume scale from 0 percent to 100 percent in 1 percent or smaller increments. [NFPA 54:8.3.1.4]
The purging of piping systems shall be in accordance with the provisions of Section 1314.6.2.1 where the piping system meets both of the following:
  1. The design operating pressure is 2 psig (14 kPa) or less.
  2. The piping being purged is constructed entirely from pipe or tubing not meeting the size and length criteria of Table 1314.6.1. [NFPA 54:8.3.2]
The piping system shall be purged in accordance with one or more of the following:
  1. The piping shall be purged with fuel gas and shall discharge to the outdoors.
  2. The piping shall be purged with fuel gas and shall discharge to the indoors or outdoors through an appliance burner not located in a combustion chamber. Such burner shall be provided with a continuous source of ignition.
  3. The piping shall be purged with fuel gas and shall discharge to the indoors or outdoors through a burner that has a continuous source of ignition and that is designed for such purpose.
  4. The piping shall be purged with fuel gas that is discharge to the indoors or outdoors, and the point of discharge shall be monitored with a listed combustible gas detector in accordance with Section 1314.6.2.2. Purging shall be stopped where fuel gas is detected.
  5. The piping shall be purged by the gas supplier in accordance with written procedures. [NFPA 54:8.3.2.1]
Combustible gas detectors shall be listed and shall be calibrated or tested in accordance with the manufacturer's instructions. Combustible gas detectors shall be capable of indicating the presence of fuel gas. [NFPA 54:8.3.2.2]
After the piping system has been placed in operation, appliances and equipment shall be purged before being placed into operation. [NFPA 54:8.3.3]
The following regulations shall comply with this section and Section 1316.0, shall be the standard for the installation of gas piping. Natural gas regulations and tables are based on the use of gas having a specific gravity of 0.60, supplied at 6 to 8 inches water column (1.5 kPa to 1.9 kPa) pressure at the outlet of the meter or regulator. For undiluted liquefied petroleum gas, gas piping shall be permitted to be sized at 11 inches water column (2.7 kPa) pressure at the outlet of the meter or regulator and specific gravity of 1.50.

    Where gas of a different specific gravity is to be delivered, the serving gas supplier shall be permitted to be contacted for specific gravity conversion factors to use in sizing piping systems from the pipe sizing tables in this chapter.
The hourly volume of gas required at each piping outlet shall be taken as not less than the maximum hourly rating as specified by the manufacturer of the appliance or appliances to be connected to each such outlet.
Where the gas appliances to be installed have not been definitely specified, Table 1308.4.1 shall be permitted to be used as a reference to estimate requirements of typical appliances. To obtain the cubic feet per hour (m3/h) of gas required, divide the input of the appliances by the average Btu (kW•h) heating value per cubic foot (m3) of the gas. The average Btu (kW•h) per cubic foot (m3) of the gas in the area of the installation shall be permitted to be obtained from the serving gas supplier.
The size of the supply piping outlet for a gas appliance shall be not less than 12 of an inch (15 mm).

    The size of a piping outlet for a mobile home shall be not less than 34 of an inch (20 mm).
Where the pipe size is to be determined using a method in Section 1316.1.1 through Section 1316.1.3, the diameter of each pipe segment shall be obtained from the pipe sizing tables in Section 1316.2 or from the sizing equations in Section 1316.3. [NFPA 54:6.1]
The pipe size of each section of gas piping shall be determined using the longest length of piping from the point of delivery to the most remote outlet and the load of the section. [NFPA 54:6.1.1]

FIGURE 1316.1.1
EXAMPLE ILLUSTRATING USE OF TABLE 1308.4.1 AND TABLE 1316.2(1)

Problem: Determine the required pipe size of each section and outlet of the piping system shown in Figure 1316.1.1. Gas to be used has a specific gravity of 0.60 and 1100 British thermal units (Btu) per cubic foot (0.0114 kW•h/L), delivered at 8 inch water column (1.9 kPa) pressure.
For SI units: 1 foot = 304.8 mm, 1 gallon = 3.785 L, 1000 British thermal units per hour = 0.293 kW, 1 cubic foot per hour = 0.0283 m3/h

Solution:
  1. Maximum gas demand of Outlet A -
    32 cubic feet per hour (0.91 m3/h) (from Table 1308.4.1).
    Maximum gas demand of Outlet B -
    3 cubic feet per hour (0.08 m3/h) (from Table 1308.4.1).
    Maximum gas demand of Outlet C -
    59 cubic feet per hour (1.67 m3/h) (from Table 1308.4.1).
    Maximum gas demand of Outlet D -
    136 cubic feet per hour (3.85 m3/h) [150000 Btu/hour (44 kW)] divided by 1100 Btu per cubic foot (0.0114 kW•h/L)
  2. The length of pipe from the gas meter to the most remote outlet (Outlet A) is 60 feet (18288 mm).
  3. Using the length in feet column row marked 60 feet (18288 mm) in Table 1316.2(1):

    Outlet A, supplying 32 cubic feet per hour (0.91 m3/h), requires 12 of an inch (15 mm) pipe.

    Section 1, supplying Outlets A and B, or 35 cubic feet per hour (0.99 m3/h) requires 12 of an inch (15 mm) pipe.

    Section 2, supplying Outlets A, B, and C, or 94 cubic feet per hour (2.66 m3/h) requires 34 of an inch (20 mm) pipe.

    Section 3, supplying Outlets A, B, C, and D, or 230 cubic feet per hour (6.51 m3/h), requircs 1 inch (25 mm) pipe.
  4. Using the column marked 60 feet (18288 mm) in Table 1316.2(1) [no column for actual length of 55 feet (16764 mm)]:

    Outlet B supplying 3 cubic feet per hour (0.08 m3/h), requires 12 ofan inch (15 mm) pipe.

    Outlet C, supplying 59 cubic feet per hour (1.67 m3/h), requires 12 of an inch (15 mm) pipe.
  5. Using the column marked 60 feet (18288 mm) in Table 1316.2(1):

    Outlet D, supplying 136 cubic feet per hour (3.85 m3/h), requires 34 of an inch (20 mm) pipe.
Pipe shall be sized as follows:
  1. The pipe size of each section of the longest pipe run from the point of delivery to the most remote outlet shall be determined using the longest run of piping and the load of the section.
  2. The pipe size of each section of branch piping not previously sized shall be determined using the length of piping from the point of delivery to the most remote outlet in each branch and the load of the section. [NFPA 54:6.1.2]
The pipe size for each section of higher pressure gas piping shall be determined using the longest length of piping from the point of delivery to the most remote line pressure regulator. The pipe size from the line pressure regulator to each outlet shall be determined using the length of piping from the regulator to the most remote outlet served by the regulator. [NFPA 54:6.1.3]
Table 1316.2(1) through Table 1316.2(36) shall be used to size gas piping in conjunction with one of the methods described in Section 1316.1.1 through Section 1316.1.3. [NFPA54:6.2]

TABLE 1316.2(1)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.2(b)]1,2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   NA means a flow of less than 10 ft3/h (0.283 m3/h).


TABLE 1316.2(2)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.2(c)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(3)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.2(d)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(4)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.2(e)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(5)
SCHEDULE 40 METALLIC PiPE [NFPA 54: TABLE 6.2(f)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(6)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.2(g)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(7)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.2(h)]1,2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   NA means a flow of less than 10 ft3/h (0.283 m3/h).
3   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.


TABLE 1316.2(8)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.2(i)]1, 2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   NA means a flow of less than 10 ft3/h (0.283 m3/h).
3   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.


TABLE 1316.2(9)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.2(j)]1, 2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   NA means a flow of less than 10 ft3/h (0.283 m3/h).
3   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.


TABLE 1316.2(10)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.2(k)]2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Table entries are rounded to 3 significant digits.


TABLE 1316.2(11)
SEMI-RIGID COPPER TUBiNG [NFPA 54: TABLE 6.2(l)]2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Table entries are rounded to 3 significant digits.


TABLE 1316.2(12)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.2(m)]3
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Where this table is used to size the tubing upstream of a line pressure regulator, the pipe or tubing downstream of the line pressure regulator shall be sized using a pressure drop no greater than 1 inch water column (0.249 kPa).
3   Table entries are rounded to 3 significant digits.


TABLE 1316.2(13)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.2(n)]2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Table entries are rounded to 3 significant digits.


TABLE 1316.2(14)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.2(o)]1,2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water colunm = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
3   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(15)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.2(p)]1,2
For SI units: 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water colunm = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
3   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(16)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.2(q)]1,2
For SI units: 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water colunm = 0.249 kPa

Notes:
1   Table entries are rounded to 3 significant digits.
2   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
3   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(17)
CORRUGATED STAINLESS STEEL TUBiNG (CSST) [NFPA 54: TABLE 6.2(r)]1, 2, 3, 4
For SI units: 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 0.75 psi (5.17 kPa), DO NOT USE THIS TABLE. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drops across a regulator are capable of varying with flow rate.
2   CAUTION: Capacities shown in table are capable of exceeding maximum capacity for a selected regulator. Consult with regulator or tubing manufacturer for guidance.
3   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
4   Table entries are rounded to 3 significant digits.
5   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(18)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.2(s)]1, 2, 3, 4
For SI units: 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 1 psi (7 kPa), DO NOT USE THIS TABLE. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drops across a regulator are capable of varying with flow rate.
2   CAUTION: Capacities shown in table are capable of exceeding maximum capacity for a selected regulator. Consult with regulator or tubing manufacturer for guidance.
3   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
4   Table entries are rounded to 3 significant digits.
5   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(19)
POLYETHYLENE PLASTIC PIPE [NFPA 54: TABLE 6.2(t)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(20)
POLYETHYLENE PLASTIC PIPE [NFPA 54: TABLE 6.2(u)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(21)
POLYETHYlENE PLASTIC PIPE [NFPA 54: TABLE 6.2(v)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(22)
POLYETHYLENE PLASTIC TUBING [NFPA 54: TABLE 6.2(w)]2,3
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   CTS = Copper tube size.
2   Table entries are rounded to 3 significant digits.
3   NA means a flow of less than 10 ft3/h (0.283 m3/h).


TABLE 1316.2(23)
POLYETHYLENE PLASTIC TUBING [NFPA 54: TABLE 6.2(x)]2,3
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column = 0.249 kPa

Notes:
1   CTS = Copper tube size.
2   Table entries are rounded to 3 significant digits.
3   NA means a flow of less than 10 ft3/h (0.283 m3/h).


TABLE 1316.2(24)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.3(a)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(25)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.3(b)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(26)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.3(c)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(27)
SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.3(d)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 inch water column = 0.249 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(28)
SEMI-RIGID COPPER TUBING [NFPA 54:TABLE 6.3(e)]2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Table entries are rounded to 3 significant digits.


TABLE 1316.2(29)
SEMI-RIGID COPPER TUBING [NFPA 54: TABLE 6.3(f)]2, 3
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1000 British thermal units per hour = 0.293 kW, 1 inch water column = 0.249 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Table entries are rounded to 3 significant digits.
3   NA means a flow of less than 10 ft3/h (0.283 m3/h).


TABLE 1316.2(30)
SENlI-RIGID COPPER TUBING [NFPA 54: TABLE 6.3(g)]2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m3/h, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6,8947 kPa

Notes:
1   Table capacities are based on Type K copper tubing inside diameter (shown), which has the smallest inside diameter of the copper tubing products.
2   Table entries are rounded to 3 significant digits.


TABLE 1316.2(31)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.3(h)]1, 2
For SI units: 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 inch water colunm = 0.249 kPa

Notes:
1   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
2   Table entries are rounded to 3 significant digits.
3   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(32)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.3(i)]1, 2, 3, 4
For SI units: 1 foot = 304.8 mm, 1000 British thennal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 0.5 psi (3.4 kPa)[based on 13 inch water column (3.2 kPa) outlet pressure], DO NOT USE THIS TABLE. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drops across a regulator are capable of varying with flow rate.
2   CAUTION: Capacities shown in table are capable of exceeding maximum capacity for a selected regulator. Consult with regulator or tubing manufacturer for guidance.
3   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
4   Table entries are rounded to 3 significant digits.
5   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(33)
CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.3(j)]1, 2, 3, 4
For SI units: 1 foot = 304.8 mm, 1000 British thennal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

Notes:
1   Table does not include effect of pressure drop across the line regulator. Where regulator loss exceeds 0.5 psi (3.4 kPa)[based on 13 inch water column (3.2 kPa) outlet pressure], DO NOT USE THIS TABLE. Consult with regulator manufacturer for pressure drops and capacity factors. Pressure drops across a regulator are capable of varying with flow rate.
2   CAUTION: Capacities shown in table are capable of exceeding maximum capacity for a selected regulator. Consult with regulator or tubing manufacturer for guidance.
3   Table includes losses for four 90 degree (1.57 rad) bends and two end fittings. Tubing runs with larger numbers of bends, fittings, or both shall be increased by an equivalent length of tubing to the following equation: L = 1.3 n, where L is additional length (ft) of tubing and n is the number of additional fIttings, bends, or both.
4   Table entries are rounded to 3 significant digits.
5   EHD = Equivalent Hydraulic Diameter, which is a measure of the relative hydraulic efficiency between different tubing sizes. The greater the value of EHD, the greater the gas capacity of the tubing.


TABLE 1316.2(34)
POLYETHYLENE PLASTIC PIPE [NFPA 54: TABLE 6.3(k)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 inch water column = 0.249 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(35)
POLYETHYLENE PLASTIC PIPE [NFPA 54: TABLE 6.3(k)]*
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

*   Table entries are rounded to 3 significant digits.


TABLE 1316.2(36)
POLYETHYLENE PLASTIC TUBING [NFPA 54: TABLE 6.3(m)]2
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 inch water column = 0.249 kPa

Notes:
1   CTS = Copper tube size.
2   Table entries are rounded to 3 significant digits.
The inside diameter of smooth wall pipe or tubing shall be determined by Equation 1316.3(1), Equation 1316.3(2), Table 1316.3, and using the equivalent pipe length determined by Section 1316.1.1 through Section 1316.1.3. [NFPA 54:6.4]

EQUATION 1316.3(1)
LOW-PRESSURE GAS FORMULA (LESS THAN 1.5 psi)
[NFPA 54:6.4.1]


Where:
D = inside diameter of pipe, inches
Q = input rate appliance(s), cubic feet per hour at 60°F
and 30 inch mercury column
L = equivalent length of pipe, feet
ΔH = pressure drop, in. water column
Cr = in accordance with Table 1316.3


EQUATION 1316.3(2)
HIGH-PRESSURE GAS FORMULA (1.5 psi AND ABOVE)
[NFPA 54:6.4.2]


Where:
D = inside diameter of pipe, inches
Q = input rate appliance(s), cubic feet per hour at 60°F
and 30 inch mercury column
P1 = upstream pressure, psia (P1 + 14.7)
P2 = downstream pressure, psia (P2 + 14.7)
L = equivalent length of pipe, feet
Cr = in accordance with Table 1316.3
Y = in accordance with Table 1316.3
For SI units: 1 cubic foot = 0.0283 m3, 1000 British thermal units per hour = 0.293 kW, 1 inch = 25 mm, 1 foot = 304.8 mm, 1 pound-force per square inch = 6.8947 kPa, °C = (°F-32)/1.8, 1 inch mercury column = 3.39 kPa, 1 inch water column = 0.249 kPa

TABLE 1316.3
Cr AND Y FOR NATURAL GAS AND UNDILUTED PROPANE
AT STANDARD CONDITIONS
[NFPA 54: TABLE 6.4.2]
GAS FORMULA FACTORS
Cr Y
Natural Gas 0.6094 0.9992
Undiluted Propane 1.2462 0.9910
To determine the size of each section of pipe in a system within the range of Table 1316.2(1) through Table 1316.2(36), proceed as follows:
  1. Measure the length of the pipe from the gas meter location to the most remote outlet on the system.
  2. Select the length in feet column and row showing the distance, or the next longer distance where the table does not give the exact length.
  3. Starting at the most remote outlet, find in the just selected the gas demand for that outlet. Where the exact figure of demand is not shown, choose the next larger figure in the row.
  4. At the top of the column in the table will be found the correct size of pipe.
  5. Using this same row, proceed in a similar manner for each section of pipe serving this outlet. For each section of pipe, determine the total gas demand supplied by that section. Where gas piping sections serve both heating and cooling appliances and the installation prevents both units from operating simultaneously, the larger of the two demand loads needs to be used in sizing these sections.
  6. Size each section of branch piping not previously sized by measuring the distance from the gas meter location to the most remote outlet in that branch and follow the procedures of steps 2, 3, 4, and 5 above. Size branch piping in the order of their distance from the meter location, beginning with the most distant outlet not previously sized.
For conditions other than those covered by Section 1316.1, such as longer runs or greater gas demands, the size of each gas piping system shall be determined by standard engineering methods acceptable to the Authority Having Jurisdiction, and each such system shall be so designed that the total pressure drop between the meter or other point of supply and an outlet where full demand is being supplied to outlets, shall be in accordance with the requirements of Section 1308.4.
Where the gas pressure exceeds 14 inches (3.5 kPa) or less than 6 inches (1.5 kPa) of water column, or where diversity demand factors are used, the design, pipe, sizing, materials, location, and use of such systems first shall be approved by the Authority Having Jurisdiction. Piping systems designed for pressures exceeding the serving gas supplier's standard delivery pressure shall have prior verification from the gas supplier of the availability of the design pressure.
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