CMC · California Mechanical Code
What piping materials and joining methods are acceptable?
In short: the CMC requires listed materials meeting the cited ASTM/ASME standards and installed with approved joining methods. Cast iron is banned; steel/stainless/wrought‑iron must be **Schedule 40** or heavier; tubing cannot be used with gases that would corrode it; brazing must use filler > **1000°F (538°C)**; and press, welded, flanged, threaded (size‑limited) or brazed joints are used only where the Code allows.
Last reviewed: July 6, 2026
What the code requires — plain English
The California Mechanical Code requires that piping materials and joints used for fuel‑gas systems be listed, suitable for the gas and service conditions, and installed in the manners the Code specifies. See § 1308.4 for the general requirement that materials comply with the subsections that follow. § 1308.4, § 1308.4.2, and § 1308.4.3 are the controlling provisions for which pipe and tubing types are acceptable and which limitations apply.
Use materials and joining methods that the Code allows, that are compatible with the gas, pressure and temperature, and that meet the listed ASTM/ASME standards required by the Code. (Key rule: § 1308.4.)
Requirements in detail
Bolded on first mention: Metallic pipe, Metallic tubing, Schedule 40, and the controlling sections § 1308.4, § 1308.4.2, § 1308.4.3.
High‑level constraints you must follow (synthesized from the Code):
- Materials used in gas piping must comply with the sub‑sections of § 1308.4.
- Cast‑iron pipe is not permitted for fuel gas service. See § 1308.4.2.1.
- For steel, stainless steel, and wrought‑iron, the pipe must be at least Schedule 40 and comply with ASME B36.10M and specified ASTM standards. See § 1308.4.2.2.
- Tubing shall not be used with gases corrosive to the tubing material; specific tubing types must meet their ASTM standards. See § 1308.4.3 and subsections.
Decision table — material, joining methods, limits
| Material / Type | Minimum / Standard required | Allowed joining methods (decision‑relevant) | Key limits / notes | Code Reference |
|---|---|---|---|---|
| Cast iron pipe | — | NOT permitted | Cast iron prohibited for gas piping | § 1308.4.2.1 |
| Steel, stainless steel, wrought‑iron pipe | ≥ Schedule 40; ASME B36.10M and ASTM A53/A106/A312 | Threaded, flanged, brazed, welded, press‑connect (see joints rules) | Threaded fittings > 4 in (100 mm) not permitted; use compatible fittings | § 1308.4.2.2 and joint rules § 1308.4.7 |
| Copper / copper alloy pipe or tubing | Applicable copper tube standards (see Code) | Brazing (with filler melt > 1000°F (538°C)), approved tubing fittings, press‑connect fittings listed to ANSI/CSA LC 4/6.32 | Brazing filler max 0.05% phosphorus if phosphorus used; flared allowed only on nonferrous systems when proven suitable | Copper tubing joint rules in § 1308.4.7.2 and brazing requirements § 1308.4.7 |
| Stainless steel tubing | ASTM tubing standards (per subsection) | Welding, brazing (>1000°F), approved fittings, press‑connect | Brazing alloys/flux must be manufacturer‑recommended for stainless alloys | § 1308.4.3 and § 1308.4.7.3 |
| Aluminum alloy pipe | ASTM B241 (but alloy 5456 prohibited) | Use matching aluminum alloy fittings | Must be coated where contacting masonry/insulation; not permitted exterior or underground | § 1308.4.2.4 |
| Metallic tubing (general) | Tubing must meet referenced ASTM standards (e.g., steel tubing ASTM A254) | Per tubing type (see copper/stainless rules) | Tubing may not be used with corrosive gases to the tubing material | § 1308.4.3 and § 1308.4.3.1 |
Notes:
- When the Code requires a particular ASTM/ASME standard for a material, installation that deviates from that standard is not permitted unless specifically allowed. See § 1308.4.
- The Code requires used (recycled) components only when proven clean and adequate. See § 1308.4.1.
Joining / joint performance rules (summary)
- Joints for Schedule 40 and heavier pipe may be threaded, flanged, brazed, welded, or assembled with press‑connect fittings listed to ANSI/CSA LC 4/CSA 6.32. See § 1308.4.7.1.
- Brazing materials must have a melting point > 1000°F (538°C); brazing alloys must not contain more than 0.05% phosphorus where required by the Code. See § 1308.4.7.1 and related subsections.
- Copper tubing may be brazed (same melting and phosphorus limits), assembled with approved gas tubing fittings, or installed with listed press‑connect fittings. See § 1308.4.7.2.
- Stainless steel tubing may be welded, brazed (per mineral limits and manufacturer‑recommended brazing alloys/flux), or assembled with approved fittings or listed press‑connect fittings. See § 1308.4.7.3.
- Flared joints are limited to nonferrous systems and only when experience/tests show suitability and provisions prevent separation. See § 1308.4.7.4.
Exceptions & special cases
- Reused pipe/fittings: Allowed only if they are free of foreign materials and shown to be adequate for the intended service (§ 1308.4.1).
- Aluminum alloy pipe: Prohibited for exterior or underground use; alloy 5456 is specifically prohibited by the referenced materials standard. See § 1308.4.2.4.
- Tubing and corrosive gases: Tubing must not be used where the gas is corrosive to the tubing material (see § 1308.4.3). If gas composition is corrosive, choose materials rated for that gas.
- Threaded fittings: Threaded fittings are restricted in size (threaded fittings in sizes exceeding 4 inches (100 mm) shall not be used) — check the metallic fittings subsection for limits. See § 1308.4.7.5(1).
If a needed limitation or detail does not appear in the retrieved sections, the Code does not supply it here — you must consult the referenced standards or other CMC sections for the missing detail. (If you want, I can pull more Code text or the referenced ASTM/ASME standards.)
Common mistakes
- Assuming any metal pipe is acceptable — cast iron is explicitly prohibited for fuel gas. See § 1308.4.2.1.
- Brazing with low‑temperature filler or phosphorus‑heavy alloys for nonferrous systems — brazing filler must melt above 1000°F (538°C) and phosphorus limits apply. See § 1308.4.7.1.
- Using tubing in corrosive atmospheres without verifying compatibility — tubing cannot be used with gases corrosive to the tubing material. See § 1308.4.3.
- Threading Schedule 80 pipe and not reducing allowable pressure — the Code permits threading Schedule 80 but requires the pressure rating to be reduced (see related threading guidance). Check the threading specs table and local rules. See § 1308.4.7 and referenced tables.
- Mixing dissimilar metals for fittings without ensuring material compatibility — metallic fittings must be of the compatible materials listed by the Code (see metallic fittings rules). See § 1308.4.7.5.
Worked example — residential range service
Scenario: You are running a new 1‑inch gas branch from a steel riser to a residential gas range inside a dwelling.
Step 1 — Material selection:
- Choose steel pipe complying with ASME B36.10M and Schedule 40 minimum (Code requires Schedule 40 or greater for steel). See § 1308.4.2.2.
Step 2 — Joining method:
- For Schedule 40 steel, acceptable joints include threaded or welded. If you plan threaded joints, ensure the fitting sizes and thread spec comply. See § 1308.4.7.1.
Step 3 — Thread limits and compatibility:
- If any threaded fittings exceed 4 in (100 mm) (they won’t in a 1‑inch run), the Code disallows threaded fittings larger than that size; not applicable here but good to note. See § 1308.4.7.5(1).
Step 4 — Pressure and inspection:
- Confirm joint sealing materials and thread sealant are compatible with the gas (thread sealant must be resistant to constituents of the gas). The pipe must be tested per installation/inspection rules (sizing/pressure drop per § 1308.3 and piping installation sections). See § 1308.3 and § 1308.4.
Result: A 1‑inch Schedule 40 steel pipe with properly threaded or welded connections (installed and tested per Code) meets the material and joining rules cited in § 1308.4 and its subsections.
Related provisions (useful cross‑references)
- § 1308.4 — Acceptable piping materials and joining methods (general requirement).
- § 1308.4.2 — Metallic pipe requirements (cast iron prohibition, schedule, referenced ASTM lists).
- § 1308.4.3 — Metallic tubing (tubing limitations and ASTM references).
- § 1308.4.7 — Pipe and tubing joint specifics (threaded, brazed, welded, press‑connect, flared joints, brazing requirements).
- § 1308.3 — Gas piping sizing and allowable pressure drop (required when selecting sizes compatible with chosen materials).
- § 1310.2 — CSST piping systems (if you are considering CSST, other rules apply).
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 5.3.2.3 High relevance — show source text
The total connected hourly load shall be used as the basis for piping sizing, assuming all appliances are operating at full capacity simultaneously. Exception: Sizing shall be permitted to be based upon established load diversity factors. [NFPA 54:5.3.2.3] 1308.3.2 Sizing Methods. Gas piping shall be sized in accordance with one of the following: (1) Pipe sizing tables or sizing equations in this chapter.
(2) Sizing tables included in a listed piping system manufacturer’s installation instructions.
(3) Engineering methods. [NFPA 54:5.3.3] 1308.3.3 Allowable Pressure Drop. The design pressure loss in a piping system from the point of delivery to the inlet connection of all appliances served shall be such that the supply pressure at each appliance inlet is greater than or equal to the minimum pressure required by the appliance. [NFPA 54:5.3.4] 1308.4 Acceptable Piping Materials and Joining Methods. Materials used for piping systems shall comply with the requirements of Section 1308.4.1 through Section 1308.4.4.2.3. {NFPA 54:5.5.1.1} 1308.4.1 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 54:5.5.1.2] 1308.4.2 Metallic Pipe. Metallic pipe shall be in accordance with Section 1308.4.2.1 through Section 1308.4.2.4.
1308.4.2.1 Cast Iron. Cast-iron pipe shall not be used. [NFPA 54:5.5.2.1] 1308.4.2.2 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 54:5.5.2.2}
TABLE 1308.3.1
APPROXIMATE GAS INPUT FOR TYPICAL APPLIANCES
[NFPA 54: TABLE A.5.3.2.1]
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FUEL GAS PIPING
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1308.4.3 Metallic Tubing. Tubing shall not be used with gases corrosive to the tubing material. [NFPA 54:5.5.3.1] 1308.4.3.1 Steel Tubing. Steel tubing shall comply with ASTM A254. [NFPA 54:5.5.3.2] **1308.4.3.2 Stainless Steel Tubing.
CMC § 1306.1 High relevance — show source text
1306.1 Disconnection . . . . . . . . . . . . . . . . 276
1306.2 Notice . . . . . . . . . . . . . . . . . . . . . . 276
1306.3 Capped Outlets. . . . . . . . . . . . . . . 276
1307.0 Temporary Use of Gas . . . . . . . . . 276
1307.1 General. . . . . . . . . . . . . . . . . . . . . 276
1308.0 Gas Piping System Design, Materials, and Components . . . . . 276
1308.1 Installation of Piping System . . . . 276
1308.2 Interconnections Supplying Separate Users. . . . . . . . . . . . . . . 276
1308.3 Sizing of Gas Piping Systems . . . 277
1308.4 Acceptable Piping Materials and Joining Methods . . . . . . . . . . 277
Table 1308.3.1 Approximate Gas Input for Typical Appliances . . . . . . . . . . . . 277
Table 1308.4.6.2 Specifications for Threading Metallic Pipe . . . . . . . . . . . . . . . . . 278
1308.5 Gas Meters . . . . . . . . . . . . . . . . . . 280
1308.6 Gas Pressure Regulators . . . . . . . 280
1308.7 Overpressure Protection. . . . . . . . 281
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TABLE OF CONTENTS
1308.8 Pressure Limitation
Requirements . . . . . . . . . . . . . . . . 281
1308.9 Overpressure Protection Devices. . . . . . . . . . . . . . . . . . . . . 281
1308.10 Backpressure Protection . . . . . . . 282
1308.11 Low-Pressure Protection . . . . . . . 282
1308.12 Shutoff Valves . . . . . . . . . . . . . . . 282
Table 1308.12 Manual Gas Valve Standards. . . . 282
1308.13 Expansion and Flexibility . . . . . . . 282
1308.14 Pressure Regulator and Pressure Control Venting . . . . . . . 282
1309.0 Excess Flow Valve . . . . . . . . . . . . 283
1309.1 General. . . . . . . . . . . . . . . . . . . . . 283
1310.0 Gas Piping Installation . . . . . . . . . 283
1310.1 Piping Underground . . . . . . . . . . . 283
1310.2 CSST Piping Systems . . . . . . . . . 284
1310.3 Installation of Aboveground Piping . . . . . . . . . . . . . . . . . . . . . . 284
Table 1310.3.5.1 Support of Piping . . . . . . . . . . . . . 285
CMC § 5.5.2.4 High relevance — show source text
Threaded copper, copper alloy, or aluminum alloy pipe shall not be used with gases corrosive to such material. [NFPA 54:5.5.2.4]
1308.4.2.4 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 54:5.5.2.5]
Aluminum alloy pipe shall not be used in exterior locations or underground. [NFPA 54:5.5.2.6]
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ular supply shall be permitted to be used for this purpose.
[NFPA 54:5.2.2.1 – 5.2.2.2] 1308.3 Sizing of Gas Piping Systems. Gas piping systems shall be of such size and so installed as to provide a supply of gas sufficient 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 54:5.3.1]
1308.3.1 Maximum Gas Demand. The volumetric flow rate of gas to be provided shall be the sum of the maximum input of the appliances served. The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2 000 feet (610 m). [NFPA 54:5.3.2.1 – 5.3.2.2] Where the input rating is not indicated, the gas supplier, appliance manufacturer, or a qualified agency shall be contacted or the rating from Table 1308.3.1 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 piping sizing, assuming all appliances are operating at full capacity simultaneously. Exception: Sizing shall be permitted to be based upon established load diversity factors. [NFPA 54:5.3.2.3] 1308.3.2 Sizing Methods. Gas piping shall be sized in accordance with one of the following: (1) Pipe sizing tables or sizing equations in this chapter.
(2) Sizing tables included in a listed piping system manufacturer’s installation instructions.
(3) Engineering methods. [NFPA 54:5.3.3] 1308.3.3 Allowable Pressure Drop. The design pressure loss in a piping system from the point of delivery to the inlet connection of all appliances served shall be such that the supply pressure at each appliance inlet is greater than or equal to the minimum pressure required by the appliance. [NFPA 54:5.3.4] 1308.4 Acceptable Piping Materials and Joining Methods. Materials used for piping systems shall comply with the requirements of Section 1308.4.1 through Section 1308.4.4.2.3. {NFPA 54:5.5.1.1} 1308.4.1 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.
CMC § 5.5.8 High relevance — show source text
Joints shall be made with the joining method recommended by the pipe manufacturer. Polyethylene heat fusion fittings shall be marked “ASTM D2513.” Polyamide heat fusion fittings shall be marked "ASTM F2945." [NFPA 54:5.5.8(2)]
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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 54:5.5.7] 1308.4.7.1 Pipe Joints. Schedule 40 and heavier pipe joints shall be threaded, flanged, brazed, welded, or assembled with press-connect fittings listed to CSA/ANSI LC 4/CSA 6.32.
(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 54:5.5.7.1} 1308.4.7.2 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/ANSI LC 4/CSA 6.32. Brazing alloys shall not contain more than 0.05 percent phosphorus. [NFPA 54:5.5.7.2] 1308.4.7.3 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/ANSI LC 4/CSA 6.32. Brazing alloys and fluxes shall be recommended by the manufacturer for use on stainless steel alloys. [NFPA 54:5.5.7.3] 1308.4.7.4 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 54:5.5.7.4] 1308.4.7.5 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 castiron. (3) Fittings used with copper or copper alloy pipe shall be copper or copper alloy. (4) Fittings used with aluminum alloy pipe shall be aluminum alloy. (5) Cast-iron fittings shall comply with the following: (a) Flanges shall be permitted.
(b) Bushings shall not be used.
(c) Fittings shall not be used in systems containing flammable gas-air mixtures.
(d) Fittings in sizes 4 inches (100 mm) and larger shall not be used indoors unless
CMC § 3.14 High relevance — show source text
Where the proper melt is obtained, the pipe and fitting shall be joined by inserting one into the other with applied force. The joint shall fuse together and remain undisturbed until cool.
(4) Mechanical joints between PE pipe or tubing and fittings shall include insert and mechanical compression fittings that provide a pressure seal resistance to pullout. Joints for insert fittings shall be made by cutting the pipe square, using a cutter designed for plastic piping, and removal of sharp edges. Two stainless steel clamps shall be placed over the end of the pipe. Fittings shall be checked for proper size based on the diameter of the pipe. The end of pipe shall be placed over the barbed insert fitting, making contact with the fitting shoulder. Clamps shall be positioned equal to 180 degrees (3.14 rad) apart and shall be tightened to provide a leak tight joint. Compression type couplings and fittings shall be permitted for use in joining PE piping and tubing. Stiffeners that extend beyond the clamp or nut shall be prohibited. Bends shall be not less than 30 pipe diameters, or the coil radius where bending with the coil. Bends shall not be permitted closer than 10 pipe diameters of a fitting or valve. Mechanical joints shall be designed for their intended use. 1211.10 Polyethylene/Aluminum/Polyethylene (PE- AL-PE). Joints between polyethylene/aluminum/polyethylene (PE-AL-PE) pipe and fittings shall be installed in accordance with one of the following methods: (1) Mechanical joints for PE-AL-PE pipe or tubing and fittings shall be either of the metal insert fittings with a split ring and compression nut or metal insert fittings with copper crimp rings. Metal insert fittings shall comply with ASTM F1974. Crimp insert fittings shall be joined to the pipe by placing the copper crimp ring around the outer circumference of the pipe, forcing the pipe material into the space formed by the ribs on the fitting until the pipe contacts the shoulder of the fitting. The crimp ring shall then be positioned on the pipe so the edge of the crimp ring is [1] / 8 of an inch (3.2 mm) to [1] / 4 of an inch (6.4 mm) from the end of the pipe. The jaws of the crimping tool shall be centered over the crimp ring and tool perpendicular to the barb. The jaws shall be closed around the crimp ring and shall not be crimped more than once. (2) Compression joints for PE-AL-PE pipe or tubing and fittings shall be joined through the compression of a split ring, by a compression nut around the circumference of
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HYDRONICS
shall be a soldered, brazed, flared, or pressed joint and the connection between the threaded pipe and the fitting shall be made with a standard pipe size threaded joint.
1211.16.2 Plastic Pipe to Other Materials. Where connecting plastic pipe to other types of plastic or other types of piping material; approved listed adapter or transition fittings and listed for the specific transition intended shall be used. Except as provided in the plumbing code, PVC pipe and fittings shall not be solvent welded to any other unlike material.
1212.0 Valves.
CMC § 2.25 High relevance — show source text
00|2.25|0.70|DR|3.70|1.05|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|33 mil cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|16|3.85|1.45|DR|DR|3.40|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|33 mil cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|24|3.40|DR|DR|DR|2.70|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#8 Screw|Steel thick-
ness plus 3
threads|12|3.00|1.80|DR|DR|3.00|0.65|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#8 Screw|Steel thick-
ness plus 3
threads|16|3.00|1.00|DR|DR|2.85|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#8 Screw|Steel thick-
ness plus 3
threads|24|2.85|DR|DR|DR|2.20|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|12|4.00|3.85|2.80|1.80|4.00|3.05|1.50|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|16|4.00|3.30|1.95|0.60|4.00|2.25|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|24|4.00|2.25|DR|DR|4.00|0.65|DR|DR| |For SI: 1 inch = 25.4 mm, 1 pound per square foot (psf) = 0.0479 kPa, 1 pound per square inch = 0.00689 MPa.
DR = Design Required, o.c. = on center.
a. Wood furring shall be spruce-pine-fir or any softwood species with a specific gravity of 0.42 or greater.CMC § 20.1. High relevance — show source text
(2) Solvent cement joints for PVC pipe and fittings shall be clean from dirt and moisture. Pipe shall be cut square and pipe shall be deburred. Where surfaces to be joined are cleaned and free of dirt, moisture, oil, and other foreign material, apply primer purple in color in accordance with ASTM F656. Primer shall be applied until the surface of the pipe and fitting is softened. Solvent cements in accordance with ASTM D2564 shall be applied to all joint surfaces. Joints shall be made while both the inside socket surface and outside surface of pipe are wet with solvent cement. Hold joint in place and undisturbed for 1 minute after assembly.
(3) Threads shall comply with ASME B1.20.1. A minimum of Schedule 80 shall be permitted to be threaded; however, the pressure rating shall be reduced by 50 percent. The use of molded fittings shall not result in a 50 per
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(1) Butt-fusion joints shall be installed in accordance with ASTM F2620 and shall be made by heating the squared ends of two pipes, pipe and fitting, or two fittings by holding ends against a heated element. The heated element shall be removed where the proper melt is obtained, and joined ends shall be placed together with applied force. (2) Electro-fusion joints shall be heated internally by a conductor at the interface of the joint. Align and restrain fitting to pipe to prevent movement and apply electric current to the fitting. Turn off the current when the proper time has elapse to heat the joint. The joint shall fuse together and remain undisturbed until cool. (3) Socket-fusion joints shall be installed in accordance ASTM F2620 and shall be made by simultaneously heating the outside surface of a pipe end and the inside of a fitting socket. Where the proper melt is obtained, the pipe and fitting shall be joined by inserting one into the other with applied force. The joint shall fuse together and remain undisturbed until cool.
(4) Mechanical joints between PE pipe or tubing and fittings shall include insert and mechanical compression fittings that provide a pressure seal resistance to pullout. Joints for insert fittings shall be made by cutting the pipe square, using a cutter designed for plastic piping, and removal of sharp edges. Two stainless steel clamps shall be placed over the end of the pipe. Fittings shall be checked for proper size based on the diameter of the pipe. The end of pipe shall be placed over the barbed insert fitting, making contact with the fitting shoulder. Clamps shall be positioned equal to 180 degrees (3.14 rad) apart and shall be tightened to provide a leak tight joint. Compression type couplings and fittings shall be permitted for use in joining PE piping and tubing. Stiffeners that extend beyond the clamp or nut shall be prohibited. Bends shall be not less than 30 pipe diameters, or the coil radius where bending with the coil. Bends shall not be permitted closer than 10 pipe diameters of a fitting or valve. Mechanical joints shall be designed for their intended use. 1211.10 Polyethylene/Aluminum/Polyethylene (PE- AL-PE). Joints between polyethylene/aluminum/polyethylene (PE-AL-PE) pipe and fittings shall be installed in accordance with one of the following methods: (1) Mechanical joints for PE-AL-PE pipe or tubing and fittings shall be either of the metal insert fittings with a split ring and compression nut or metal insert fittings with copper crimp rings.
CMC § 1320.0 High relevance — show source text
1320.0 Joints and Connections.
1320.1 General. This section sets forth the requirements for pipe joint installations for a medical gas or vacuum system. 1320.2 Changes in Direction. Positive pressure patient gas systems, medical support gas systems, and vacuum systems constructed of hard-drawn seamless copper or stainless steel tubing shall have all turns, offsets, and other changes in direction made using fittings or techniques appropriate to any of the following acceptable joining methods:
(1) Brazing, as described in Section 1321.0.
(2) Welding, as described in Section 1322.1 through Section 1322.2.1.
(3) Memory metal fittings, as described in Section 1322.3.
(4) Axially swaged, elastic preload fittings, as described in Section 1322.4.
(5) Threaded, as described in Section 1322.5. [NFPA 99:5.1.10.3.1]
1320.2.1 Medical Vacuum Systems. Vacuum systems and WAGD systems fabricated from copper tubing shall be permitted to have branch connections made using mechanically formed, drilled, and extruded teebranch connections that are formed in accordance with
the tool manufacturer’s instructions. Such branch connections shall be joined by brazing, as described in Section 1321.0. [NFPA 99:5.1.10.3.3]
1321.0 Brazed Joints.
1321.1 Brazed Joints and Fittings. Fittings shall be wrought-copper capillary fittings complying with ASME B16.22, or brazed fittings complying with ASME B16.50. Cast copper alloy fittings shall not be permitted.
Brazed joints shall be made using a brazing alloy that exhibits a melting temperature in excess of 1000°F (538°C) to retain the integrity of the piping system in the event of fire exposure. [NFPA 99:5.1.10.4.1.1 – 5.1.10.4.1.3]
1321.2 Tube Joints. Brazed tube joints shall be the socket type. [NFPA 99:5.1.10.4.1.4]
1321.3 Filler Metals. Filler metals shall bond with and be metallurgically compatible with the base metals being joined.
Filler metals shall comply with AWS A5.8. [NFPA 99:5.1.10.4.1.5, 5.1.10.4.1.6]
1321.4 Copper-to-Copper Joints. Copper-to-copper joints shall be brazed using a copper–phosphorus or copperphosphorus-silver brazing filler metal (BCuP series) without flux. [NFPA 99:5.1.10.4.1.7]
1321.5 Accessible. Joints to be brazed in place shall be accessible for necessary preparation, assembly, heating, filler application, cooling, cleaning, and inspection. [NFPA 99:5.1.10.4.1.9]
CMC § 705.3 High relevance — show source text
The elastomeric gasket shall comply with ASTM C564. Hubless cast-iron pipe and fittings shall be clean and free of dirt, mud, sand, and foreign materials. Cut pipe shall be free from sharp edges. Gasket shall be placed on the end of the pipe or fitting and the stainless steel shield and clamp assembly on the end of the other pipe or fitting. Pipe or fittings shall be seated against the center stop inside the elastomeric sleeve. Slide the stainless steel shield and clamp assembly into a position centered over the gasket and tighten. Bands shall be tightened using an approved calibrated torque wrench specifically set by the manufacturer of the couplings.
705.3 Copper or Copper Alloy Pipe (DWV) and Joints. Joining methods for copper or copper alloy pipe and fittings shall be installed in accordance with the manufacturer’s installation instructions and shall comply with Section 705.3.1 through Section 705.3.4.
705.3.1 Brazed Joints. Brazed joints between copper or copper alloy pipe and fittings shall be made with brazing alloys having a liquid temperature above 1000°F (538°C). The joint surfaces to be brazed shall be cleaned bright by either manual or mechanical means. Piping shall be cut square and reamed to full inside diameter. Brazing flux shall be applied to the joint surfaces where required by manufacturer’s recommendation. Brazing filler metal shall conform to AWS A5.8 and shall be
applied at the point where the pipe or tubing enters the socket of the fitting.
705.3.2 Mechanical Joints. Mechanical joints in copper or copper alloy piping shall be made with a mechanical coupling with grooved end piping or approved joint designed for the specific application.
705.3.3 Soldered Joints. Soldered joints between copper or copper alloy pipe and fittings shall be made in accordance with ASTM B828 with the following sequence of joint preparation and operation as follows: measuring and cutting, reaming, cleaning, fluxing, assembly and support, heating, applying the solder, cooling, and cleaning. Pipe shall be cut square and reamed to the full inside diameter including the removal of burrs on the outside of the pipe. Surfaces to be joined shall be cleaned bright by manual or mechanical means. Flux shall be applied to pipe and fittings and shall conform to ASTM B813, and shall become noncorrosive and nontoxic after soldering. Insert pipe into the base of the fitting and remove excess flux. Pipe and fitting shall be supported to ensure a uniform cap
illary space around the joint. Heat shall be applied using air or fuel torch with the flame perpendicular to the pipe using acetylene or an LP gas. Preheating shall depend on the size of the joint. The flame shall be moved to the fitting cup and alternate between the pipe and fitting. Solder conforming to ASTM B32 shall be applied to the joint surfaces until capillary action draws the molten solder into the cup. Joint surfaces shall not be disturbed until cool, and any remaining flux residue shall be cleaned. 705.3.4 Threaded Joints. Threaded joints for copper or copper alloy pipe shall be made with pipe threads that comply with ASME B1.20.1. Thread sealant tape or compound shall be applied only to male threads, and such material shall be approved types, insoluble in water, and nontoxic.
**705.4 Galvanized Steel Pipe and Joints.
CMC § 605.3.2 High relevance — show source text
Listed solvent cement that complies with ASTM F493 and that does not require the use of primers, yellow in color, shall be permitted to join pipe that comply with ASTM F2855 and fittings that comply with ASTM D2846, [1] ⁄ 2 of an inch (15 mm) through 2 inches (50 mm) in diameter. Apply primer where required inside the fitting and to the depth of the fitting on pipe. Apply liberal coat of cement to the outside surface of pipe to depth of fitting and inside of fitting. Place pipe inside fitting to forcefully bottom the pipe in the socket and hold together until joint is set. 605.3.2 Mechanical Joints. Mechanical joints shall include flanged, grooved, and push fit fittings. 605.3.2.1 Push Fit Fittings. Removable and nonremovable push fit fittings that employ a quick assembly push fit connector shall comply with ASSE 1061.
605.4 Ductile Iron Pipe and Joints. Ductile iron pipe and fitting joining methods shall be installed in accordance with the manufacturer’s installation instructions and shall comply with Section 605.4.1 or Section 605.4.2. 605.4.1 Mechanical Joints. Mechanical joints for ductile iron pipe and fittings shall consist of a bell that is cast integrally with the pipe or fitting and provided with an exterior flange having bolt holes and a socket with annular recesses for the sealing gasket and the plain end of the pipe or fitting. The elastomeric gasket shall comply with AWWA C111. Lubricant recommended for potable water application by the pipe manufacturer shall be applied to the gasket and plain end of the pipe. 605.4.2 Push-On Joints. Push-on joints for ductile iron pipe and fittings shall consist of a single elastomeric gasket that shall be assembled by positioning the elastomeric gasket in an annular recess in the pipe or fitting socket and forcing the plain end of the pipe or fitting into the socket. The plain end shall compress the elastomeric gasket to form a positive seal and shall be designed so that the elastomeric gasket shall be locked in place against displacement. The elastomeric gasket shall comply with AWWA C111. Lubricant recommended for potable water application by the pipe manufacturer shall be applied to the gasket and plain end of the pipe.
150 2025 CALIFORNIA PLUMBING CODE
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WATER SUPPLY AND DISTRIBUTION
605.5 Galvanized Steel Pipe and Joints. Galvanized steel pipe and fitting joining methods shall be installed in accordance with the manufacturer’s installation instructions and shall comply with Section 605.5.1 or Section 605.5.2.
605.5.1 Mechanical Joints. Mechanical joints shall be made with an approved and listed elastomeric gasket.
CMC § 18.6 High relevance — show source text
** Flexible metallic (copper and stainless steel), reinforced flexible, braided stainless steel, or polymer braided with EPDM core connectors that connect a water heater to the piping system shall comply with ASME A112.18.6/CSA B125.6. Copper, copper alloy, or stainless steel flexible connectors shall not exceed 24 inches (610 mm). PEX, PEX-AL-PEX, PE-AL-PE, or PE-RT tubing shall not be installed within the first 18 inches (457 mm) of piping connected to a water heater. [BSC, HCD 1 & HCD 2] PEX-AL-PEX is not adopted for use in potable water supply and distribution systems.
605.0 Joints and Connections.
605.1 Copper or Copper Alloy Pipe, Tubing, and Joints. Joining methods for copper or copper alloy pipe, tubing, and fittings shall be installed in accordance with the manufacturer’s installation instructions and shall comply with Section 605.1.1 through Section 605.1.5. 605.1.1 Brazed Joints. Brazed joints between copper or copper alloy pipe or tubing and fittings shall be made with brazing alloys having a liquid temperature above 1000°F (538°C). The joint surfaces to be brazed shall be cleaned bright by either manual or mechanical means. Tubing shall be cut square and reamed to full inside diameter. Brazing flux shall be applied to the joint surfaces where required by manufacturer’s recommendation. Brazing filler metal shall conform to AWS A5.8 and shall be applied at the point where the pipe or tubing enters the socket of the fitting. 605.1.2 Flared Joints. Flared joints for soft copper or copper alloy water tubing shall be made with fittings that comply with the applicable standards referenced in Table 604.1. Pipe or tubing shall be cut square using an appropriate tubing cutter. The tubing shall be reamed to full inside diameter, resized to round, and expanded with a proper flaring tool.
605.1.3 Mechanical Joints. Mechanical joints shall include, but are not limited to, compression, flanged, grooved, pressed, and push fit fittings. 605.1.3.1 Mechanically Formed Tee Fittings. Mechanically formed tee fittings shall have extracted collars that shall be formed in a continuous operation consisting of drilling a pilot hole and drawing out the pipe or tube surface to form a collar having a height not less than three times the thickness of the branch tube wall. The branch pipe or tube shall be notched to conform to the inner curve of the run pipe or tube and shall have two dimple depth stops to ensure that penetration of the branch pipe or tube into the collar is of a depth for brazing and that the branch pipe or tube does not obstruct the flow in the main line pipe or tube. Dimple depth stops shall be in line with the run of the pipe or tube. The second dimple shall be ¼ of an inch (6.4 mm) above the first and shall serve as a visual point of inspection. Fittings and joints shall be made by brazing. Soldered joints shall not be permitted. 605.1.3.2 Press-Connect Fittings. Press-connect fittings for copper or copper alloy pipe or tubing shall have an elastomeric o-ring that forms the joint.
CMC § 1703.4.2 High relevance — show source text
(1) Butt-fusion joints shall be made in accordance with ASTM F2620.
(2) Socket-fusion joints shall be made in accordance with ASTM F2620.
(3) Electrofusion joints shall be made in accordance with ASTM F1055.
1703.4.2 Polyethylene of Raised Temperature (PE-RT). Polyethylene of raised temperature tubing shall be manufactured in accordance with the standards
listed in Table 1703.2. Tubing shall have a minimum wall thickness equal to SDR 9 and shall have a minimum pressure rating of not less than 160 psi (1103 kPa) at 73°F (23°C).
Polyethylene of raised temperature tubing shall be manufactured from a PE compound that has a pipe material designation code of PE 2708, PE 3608, or PE 4710 as defined in the applicable standards referenced in Table 1703.2, with a cell classification in accordance with ASTM D3350 appropriate for the material designation code.
1703.4.2.1 Joining Methods for Polyethylene of Raised Temperature (PE-RT). Joints between polyethylene of raised temperature (PE-RT) tubing and fittings shall be installed in accordance with the manufacturer’s installation instructions and the
appropriate standards listed in accordance with Table 1703.3.
1703.4.3 Cross-Linked Polyethylene (PEX). Crosslinked polyethylene pipe shall be manufactured in accordance with the standards listed in Table 1703.2. PEX
shall have a minimum tubing material designation code of PEX 1206 and shall have a minimum pressure rating of not less than 160 psi (1103 kPa) at 73°F (23°C).
1703.4.3.1 Joining Methods for Cross- Linked Polyethylene Tubing. Joints between cross-linked polyethylene (PEX) pipe or tubing and fittings shall be installed in accordance with the manufacturer’s installation instructions and the
appropriate standards in accordance with Table 1703.3.
1703.5 Indoor Piping. Indoor piping, fittings, and accessories that are part of the groundwater system shall be in accordance with Chapter 12. Such materials shall be rated for the operating temperature and pressures of the system and shall be compatible with the type of transfer medium.
1704.0 Heat Pumps.
1704.1 Heat Pump Distribution System. The heat pump distribution system shall be designed as follows:
(1) Individual heat pumps shall have the capacity to handle the peak load for each zone at its peak hour.
(2) Distribution piping and fittings shall be insulated to prevent condensation inside the building.
(3) An isolation valve shall be installed on both supply and return of each unit.
(4) Condensate drains on heat pumps shall be installed in accordance with the manufacturer’s installation instruc tions.
(5) Air filters shall be installed for heat pump units.
(6) Drain valves shall be installed at the base of each supply and return pipe riser for system flushing.
(7) Piping shall be supported in accordance with Section 313.0 and provisions for vibration, expansion or contraction shall be provided.
(8) Specifications for each heat pump, the heating and cooling capacity, the fluid flow rate, the airflow rate, and the external pressure or head shall be provided on the construction documents.
Frequently asked questions
Can I use cast‑iron pipe for natural gas?
No. Cast‑iron pipe is prohibited for fuel gas systems under § 1308.4.2.1.
Is brazing allowed for copper gas tubing?
Yes — copper tubing may be brazed, but the brazing filler must have a melting point above 1000°F (538°C) and phosphorus limits apply. See § 1308.4.7.2 and § 1308.4.7.1.
Are threaded joints acceptable?
Threaded joints are permitted for Schedule 40 and heavier metallic pipe where appropriate, but threaded fittings in sizes exceeding 4 inches (100 mm) shall not be used. See § 1308.4.7.1 and § 1308.4.7.5(1).
Can I use tubing for corrosive gas mixtures?
No — tubing shall not be used with gases corrosive to the tubing material; select materials rated for the gas per § 1308.4.3.
Are press‑connect fittings allowed?
Yes — press‑connect fittings listed to ANSI/CSA LC 4/CSA 6.32 are an acceptable assembly method for certain pipe/tubing types per the joint rules in § 1308.4.7.
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