1308.5 Acceptable Piping Materials and Joining

California Mechanical Code (Title 24, Part 4) · 2022 edition · updated 2026-09-10 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

Methods. Materials used for piping systems shall either comply with the requirements of this chapter or be acceptable to the Authority Having Jurisdiction. [NFPA 54:5.6.1.1]

1308.5.1 Used Materials. Pipe, fittings, valves, or other materials shall not be used again unless they are free of foreign materials and have been ascertained to be adequate for the service intended. [NFPA 54:5.6.1.2]

1308.5.1.1 Other Materials. Material not covered by the standards specifications listed herein shall meet the following criteria: (1) Be investigated and tested to determine that it is

safe and suitable for the proposed service. (2) Be recommended for that service by the manu facturer. (3) Be acceptable to the Authority Having Juris diction. [NFPA 54:5.6.1.3]

FUEL GAS PIPING

TABLE 1308.4.1 APPROXIMATE GAS INPUT FOR TYPICAL APPLIANCES

[NFPA 54: TABLE A.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	100 000 60 000 100 000 60 000
Space and Water Heating Units Hydronic boiler Single family Multifamily, per unit	120 000 75 000
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	35 000 50 000 142 800 285 000 428 400 35 000
Cooking Appliances Range, freestanding, domestic Built-in oven or broiler unit, domestic Built-in top unit, domestic	65 000 25 000 40 000
Other Appliances Refrigerator Clothes dryer, Type 1 (domestic) Gas fireplace direct vent Gas log Barbecue Gaslight	3000 35 000 40 000 80 000 40 000 2500

For SI units: 1000 British thermal units per hour = 0.293 kW

1308.5.2 Metallic Pipe. Cast-iron pipe shall not be used. [NFPA 54:5.6.2.1]

1308.5.2.1 Steel, Stainless Steel, and Wrought-Iron. Steel, stainless steel, and wroughtiron pipe shall be at least Schedule 40 and shall comply with the dimensional standards of ASME B36.10M and one of the following: (1) ASTM A53 (2) ASTM A106 (3) ASTM A312 {NFPA 54:5.6.2.2}

1308.5.2.2 Copper and Copper Alloy Pipe. Copper and copper alloy pipe shall not be used if 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). [NFPA 54:5.6.2.3]

Threaded copper, copper alloy, or aluminum alloy pipe shall not be used with gases corrosive to such material. [NFPA 54:5.6.2.4]

2022 CALIFORNIA MECHANICAL CODE 259

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FUEL GAS PIPING

1308.5.2.3 Aluminum Alloy Pipe. 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, or 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] 1308.5.3 Metallic Tubing. Tubing shall not be used with gases corrosive to the tubing material. [NFPA 54:5.6.3.1] 1308.5.3.1 Stainless Steel Tubing. Stainless steel tubing shall comply with one of the following: (1) ASTM A268 (2) ASTM A269 [NFPA 54:5.6.3.3] 1308.5.3.2 Steel Tubing. Steel tubing shall comply with ASTM A254. [NFPA 54:5.6.3.2] 1308.5.3.3 Copper and Copper Alloy Tubing. Copper and copper alloy tubing shall not be used if 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. 1308.5.3.4 Aluminum Alloy Tubing. 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, or 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 54:5.6.3.5]

1308.5.3.5 Corrugated Stainless Steel Tubing. Corrugated stainless steel tubing shall be listed in accordance with CSA LC-1. [NFPA 54:5.6.3.6] 1308.5.4 Plastic Pipe, Tubing, and Fittings. Polyethylene plastic pipe, tubing, and fittings used to supply fuel gas shall conform to ASTM D2513. Pipe to be used shall be marked “gas” and “ASTM D2513.” [NFPA 54:5.6.4.1.1] Polyamide pipe, tubing, and fittings shall be identified in and conform to ASTM F2945. Pipe to be used shall be marked “gas” and “ASTM F2945.” [NFPA 54:5.6.4.1.2] Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) plastic pipe, tubing, and fittings shall not be used to supply fuel gas. [NFPA 54:5.6.4.1.3]

1308.5.4.1 Regulator Vent Piping. Plastic pipe and fittings used to connect regulator vents to remote vent terminations shall be PVC conforming to UL 651. PVC vent piping shall not be installed indoors. [NFPA 54:5.6.4.2] 1308.5.4.2 Anodeless Risers. Anodeless risers shall comply with Section 1308.5.4.2.1 through Section 1308.5.4.2.3. [NFPA 54:5.6.4.3]

1308.5.4.2.1 Factory-Assembled Anode- less Risers. 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)]

1308.5.4.2.2 Service Head Adapters and Field-Assembled Anodeless Risers. 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 meet the requirements of Category I of ASTM D2513 and 49 CFR 192.281(e). The manufacturer shall provide the user qualified installation instructions as prescribed by 49 CFR 192.283(b).

[NFPA 54:5.6.4.3(2)]

1308.5.4.2.3 Undiluted Liquefied Petro- leum Gas Piping. The use of plastic pipe, tubing, and fittings in undiluted LP-Gas piping systems shall be in accordance with NFPA 58.

[NFPA 54:5.6.4.3(3)] 1308.5.5 Workmanship and Defects. 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] 1308.5.6 Metallic Pipe Threads. Metallic pipe and fitting threads shall be taper pipe threads and shall comply with ASME B1.20.1. [NFPA 54:5.6.6.1]

1308.5.6.1 Damaged Threads. 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 54:5.6.6.2] 1308.5.6.2 Number of Threads. Field threading of metallic pipe shall be in accordance with Table 1308.5.6.2. [NFPA 54:5.6.6.3]

TABLE 1308.5.6.2 SPECIFICATIONS FOR THREADING METALLIC PIPE

[NFPA 54: TABLE 5.6.6.3]

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IRON PIPE SIZE (inches)	APPROXIMATE LENGTH OF THREADED PORTION (inches)	APPROXIMATE NUMBER OF THREADS TO BE CUT
1⁄2	3⁄4	10
3⁄4	3⁄4	10
1	7⁄8	10
11⁄4	1	11
11⁄2	1	11
2	1	11
21⁄2	11⁄2	12
3	11⁄2	12
4	15⁄8	13

For SI units: 1 inch = 25.4 mm

260 2022 CALIFORNIA MECHANICAL CODE

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1308.5.6.3 Thread Joint Compounds. Thread joint compounds shall be resistant to the action of LP-Gas or to any other chemical constituents of the gases to be conducted through the piping. [NFPA 54:5.6.6.4] 1308.5.7 Metallic Piping Joints and Fittings. The type of piping joint used shall be suitable for the pressure and 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 any additional forces due to temperature expansion or contraction, vibration, fatigue, or the weight of the pipe and its contents. [NFPA 54:5.6.7]

1308.5.7.1 Pipe Joints. Schedule 40 and heavier pipe joints shall be threaded, flanged, brazed, welded, or assembled with press-connect fittings listed to CSA LC 4. (1) Where nonferrous pipe is brazed, the brazing

materials shall have a melting point in excess of 1000°F (538°C). (2) Brazing alloys shall not contain more than 0.05

percent phosphorus. {NFPA 54:5.6.7.1} 1308.5.7.2 Copper Tubing Joints. Copper tubing joints shall be assembled with approved gas tubing fittings, shall be brazed with a material having a melting point in excess of 1000°F (538°C), or shall be assembled with press-connect fittings listed to CSA LC 4, Press-Connect Metallic Fittings for Use in Fuel Gas Distribution Systems. Brazing alloys shall not contain more than 0.05 percent phosphorus. [NFPA 54:5.6.7.2] 1308.5.7.3 Stainless Steel Tubing Joints. Stainless steel joints shall be welded, assembled with approved tubing fittings, brazed with a material having a melting point in excess of 1000°F (538°C), or assembled with press-connect fittings listed to CSA LC 4, Press-Connect Metallic Fittings for Use in Fuel Gas Distribution Systems. Brazing alloys and fluxes shall be recommended by the manufacturer for use on stainless steel alloys. [NFPA 54:5.6.7.3] 1308.5.7.4 Flared Joints. Flared joints shall be used only in systems constructed from nonferrous pipe and tubing where experience or tests have demonstrated that the joint is suitable for the conditions and where provisions are made in the design to prevent separation of the joints. [NFPA 54:5.6.7.4] 1308.5.7.5 Metallic Pipe Fittings. Metallic fittings shall comply with the following: (1) Threaded fittings in sizes exceeding 4 inches

(100 mm) shall not be used. (2) Fittings used with steel, stainless steel, or

wrought-iron pipe shall be steel, stainless steel, copper alloy, malleable iron, or cast-iron. (3) Fittings used with copper or copper alloy pipe

shall be copper or copper alloy.

FUEL GAS PIPING

(4) Fittings used with aluminum alloy pipe shall be

aluminum alloy. (5) Cast-iron fittings shall comply with the follow ing: (a) Flanges shall be permitted. (b) Bushings shall not be used. (c) Fittings shall not be used in systems con taining flammable gas-air mixtures. (d) Fittings in sizes 4 inches (100 mm) and

larger shall not be used indoors unless approved by the Authority Having Jurisdiction. (e) 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 compressiontype tubing fittings shall be as follows: (a) Used within the fitting manufacturer’s

pressure-temperature recommendations. (b) Used within the service conditions antici pated with respect to vibration, fatigue, thermal expansion, or contraction. (c) Acceptable to the Authority Having Juris diction. (9) When pipe fittings are drilled and tapped in the

field, the operation shall be in accordance with the following: (a) The operation shall be performed on sys tems having operating pressures of 5 psi (34 kPa) or less. (b) The operation shall be performed by the

gas supplier or their designated representative. (c) The drilling and tapping operation shall be

performed in accordance with written procedures prepared by the gas supplier. (d) The fittings shall be located outdoors. (e) The tapped fitting assembly shall be

inspected and proven to be free of leaks.

[NFPA 54:5.6.7.5] 1308.5.8 Plastic Piping, Joints, and Fittings. Plastic pipe, tubing, and fittings shall be joined in accordance with the manufacturer’s instructions. Section 1308.5.8.1 through Section 1308.5.8.4 shall be observed when making such joints. [NFPA 54:5.6.8]

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2022 CALIFORNIA MECHANICAL CODE 261

1308.5.10 Flange Gaskets. 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 54:5.6.10]

1308.5.10.1 Flange Gasket Materials. Acceptable materials shall include the following: (a) Metal (plain or corrugated) (b) Composition (c) Aluminum “O” rings (d) Spiral-wound metal gaskets (e) Rubber-faced phenolic (f) Elastomeric [NFPA 54:5.6.10.1] 1308.5.10.2 Metallic Flange Gaskets. Metallic flange gaskets shall be in accordance with ASME B16.20. [NFPA 54:5.6.10.2.1] 1308.5.10.3 Non-Metallic Flange Gaskets. Non-metallic flange gaskets shall be in accordance with ASME B16.21. [NFPA 54:5.6.10.2.2] 1308.5.10.4 Full-Face Flange Gasket. Full-face flange gaskets shall be used with all non-steel flanges. [NFPA 54:5.6.10.3] 1308.5.10.5 Separated Flanges. When a flanged joint is separated, the gasket shall be replaced. [NFPA 54:5.6.10.4]