CMC · California Mechanical Code
Which piping, tubing and fittings are permitted for hydronic systems?
For homeowners: Hydronic piping and fittings must be the types the California Mechanical Code lists (Table 1210.1), be rated for your system’s temperature and pressure, use approved joints, and meet special rules for pipes in slabs and oxygen diffusion. See **§ 1210.1**, embedded‑pipe rules (§ 1221.2) and oxygen barrier rules (§ 1210.4).
Last reviewed: July 6, 2026
What the code requires — in plain English
Hydronic piping, tubing and fittings must be made of materials and joint types approved for the intended hydronic purpose, rated for the system’s operating temperature and pressure, and comply with the standards listed in Table 1210.1. See § 1210.1 for the basic rule and the specific materials table.
The single most important rule: use only materials and fittings listed in Table 1210.1 and installed per the applicable CMC provisions and manufacturer instructions (they must be rated for the system’s operating temperature and pressure).
Requirements in detail
1) Material approval and rating
- Hydronic pipe and tubing must be approved for the intended use and rated for the operating temperature and pressure of the system, per § 1210.1.
- Pipe fittings and valves must likewise be approved for the specific piping material and installation and comply with the standards referenced in Table 1210.1. § 1210.1 and the table are the controlling references.
2) Oxygen diffusion / corrosion control
- PEX and PE-RT used in closed hydronic systems must contain an oxygen barrier to limit oxygen diffusion and corrosion of ferrous components (§ 1210.4). If the closed-loop system is vented, all components must be non‑ferrous or corrosion‑resistant.
3) Joints and connections
- Joints and connections must be of an approved type, gas- and watertight, and designed for the system pressure (see § 1211.1). Manufacturer instructions and the applicable joint standards in Table 1210.1 govern acceptable methods.
- For plastic pipe embedded in concrete, solvent‑cemented joints are prohibited; plastic piping must be continuous or joined by heat fusion or other approved listed fittings consistent with Table 1210.1 and § 1221.2.3.
4) Embedded piping minimum ratings and installation
- Embedded piping (piping embedded in concrete) is limited to steel pipe, Type L copper tubing, or plastic pipe or tubing rated at not less than 80 psi at 180°F (552 kPa at 82°C). Joints in embedded piping must meet the embedded‑joint rules in § 1221.2 and § 1221.2.3.
5) Pressure testing before embedment and pour
- Piping to be embedded must be pressure‑tested prior to pouring in accordance with the testing rules (pressure of not less than one and one‑half times the hydronic system operating pressure and not less than 100 psi) and tests must be held for the required duration in the presence of the authority having jurisdiction (§ 1221.3 and § 1205.2). Note: certain plastics have manufacturer‑authorized air‑test exceptions — see § 1205.2.
Decision‑relevant table (key materials / standards)
The table below summarizes the materials and the standards cited in Table 1210.1. Use this to decide whether a material + fitting combo is allowed; always confirm the specific standard/listing on the product data sheet.
| Material (typical name) | Typical piping/tubing standard(s) | Typical fittings standard(s) | Code reference |
|---|---|---|---|
| Copper / copper alloy | ASTM B42, B43, B75, B88, B135, B251, B302, B447 | ASME B16.15, B16.18, B16.22, B16.23, B16.24, B16.26, B16.29, B16.51, ASSE 1061, ASTM F3226, IAPMO PS 117 | Table 1210.1 / § 1210.1 |
| Ductile iron | AWWA C115/A21.15, AWWA C151/A21.51 | AWWA C110/A21.101, AWWA C153/A21.53 | Table 1210.1 / § 1210.1 |
| Steel (carbon) | ASTM A53, A106, A254 | ASME B16.5, B16.9, B16.11; ASTM A420; ASTM F3226; IAPMO IGC 353; IAPMO PS 117 | Table 1210.1 / § 1210.1 |
| Stainless steel | ASTM A269, A312, A554, A778 | ASTM F1476, F1548, F3226; IAPMO IGC 353 | Table 1210.1 / § 1210.1 |
| PE (Polyethylene), PE‑RT, PEX, PEX‑AL‑PEX, PE‑AL‑PE, CPVC, PP | Referenced product standards (e.g., ASTM F2620 for fusion) and manufacturer listings | Listed/approved fittings per Table 1210.1 and manufacturer instructions (mechanical/crimp/fusion per type) | Table 1210.1 / § 1210.1; see joints rules § 1211.0 and specific subsections (e.g., § 1211.10, § 1211.16.2) |
(Notes: the Table in the code contains a fuller set of referenced standards per material category — the table above is a decision‑level extract. Always verify the exact ASTM/AWWA/ASME/io listing shown on the product approval and match to Table 1210.1.)
Exceptions & special cases
- Air testing is generally prohibited for plastic piping; however, PEX, PP‑R, PP‑RCT, PEX‑AL‑PEX, PE‑RT and PE‑AL‑PE systems may be air‑tested only if authorized by the manufacturer’s instructions and not prohibited by other codes or laws (§ 1205.2).
- Embedded piping has special allowed materials: steel, Type L copper, or plastic rated ≥ 80 psi at 180°F; and solvent‑cement joints are not allowed in embedded applications (§ 1221.2 / § 1221.2.3).
- Where oxygen diffusion is a concern (closed loops with ferrous components), use oxygen barrier tubing or make the entire system corrosion‑resistant per § 1210.4.
Common mistakes
- Installing a plastic pipe in a slab that is not rated at least 80 psi at 180°F — embedded plastics must meet that minimum rating (§ 1221.2).
- Using solvent‑cement for joints of embedded plastic piping (prohibited) — joints must be heat‑fusion or listed fittings (§ 1221.2.3).
- Failing to provide an oxygen barrier on PEX/PE‑RT in closed systems, which can lead to corrosion of ferrous components (§ 1210.4).
- Mixing fittings that are not listed for the piping material (e.g., using unlisted compression fittings or non‑listed transitions) — all transitions require listed/approved adapter fittings and compliance with Table 1210.1 and manufacturer instructions (§ 1211.16.2, § 1211.1).
- Testing only to 1.5× operating pressure when the code requires not less than 100 psi during an embedment pour — you must meet both the multiplier and the absolute minimum during pour/test (§ 1221.3, § 1205.2).
Worked example — applying the rule with numbers
Scenario: You plan to install an under‑slab hydronic loop using PE‑RT tubing embedded in a concrete slab. System design operating pressure is 50 psi and maximum fluid temperature is 180°F.
Step 1 — Material rating: PE‑RT tubing for embedment must be rated ≥ 80 psi at 180°F. If the PE‑RT product is rated 100 psi @ 180°F, it meets the embedded minimum per § 1221.2.
Step 2 — Joints/lengths: Use continuous coils or heat‑fusion/joining methods listed for PE‑RT (no solvent cement). Ensure joints meet the manufacturer’s instructions and the code joint rules in § 1211.0 and applicable subsections.
Step 3 — Pressure test before pour: Test prior to pouring at the greater of 1.5× operating pressure or 100 psi. Here, 1.5×50 psi = 75 psi, but the code requires not less than 100 psi during pour, so you must hold 100 psi for the required test period in the presence of the AHJ. (See § 1221.3 and § 1205.2.)
Step 4 — Oxygen control: If the closed loop contains ferrous components (e.g., cast‑iron heat exchangers), specify oxygen‑barrier PE‑RT or otherwise use non‑ferrous/corrosion‑resistant components per § 1210.4.
Related provisions (quick list)
- § 1210.1 — Materials; piping/tubing/fittings must comply with Table 1210.1.
- § 1210.2 — Expansion and contraction (flexible connectors, offsets for small connections).
- § 1210.3 — Hangers and supports for piping.
- § 1210.4 — Oxygen diffusion / barrier requirements for PEX and PE‑RT.
- § 1211.0 / § 1211.1 — Joints and connections; approved, gas/water‑tight.
- § 1211.10 — Specific joint methods for PE‑AL‑PE (and related details).
- § 1221.2 / § 1221.2.3 — Requirements for embedded piping and allowed materials/joint types.
- § 1221.3 — Pressure testing of embedded piping prior to pour.
- § 1205.2 — General pressure testing requirements (1.5× operating pressure; plastics testing exceptions).
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 1209.2 High relevance — show source text
Expansion tanks shall be of the closed type. Expansion tanks shall be rated for the pressure of the system. 1209.2 Installation. Expansion tanks shall be accessible for maintenance and shall be installed in accordance with the manufacturer’s installation instructions. Each expansion tank shall be equipped with a shutoff device that will remain open during operation of the hydronic system. Valve handles shall be locked open or removed to prevent from being inadvertently shut off. Provisions shall be made for draining the tank without emptying the system. Expansion tanks shall be securely fastened to or supported by the structure. Supports shall be capable of carrying twice the weight of the tank filled with water without placing a strain on connecting piping. Hot-water-heating systems incorporating hot water tanks or fluid relief columns shall be installed to prevent freezing under normal operating conditions. 1209.3 Closed-Type Tanks. Closed-type expansion tanks shall be designed for a hydrostatic test pressure of two and one-half times the allowable working pressure of the system. Expansion tanks for systems designed to operate at more than 30 pounds-force per square inch (psi) (207 kPa) shall comply with ASME BPVC Section VIII.1.
1209.4 Sizing. Expansion tanks shall be sized to accept the full expansion volume of the fluid in the system. The minimum capacity of a closed-type expansion tank shall be sized in accordance with Section 1004.4.
1210.0 Materials.
1210.1 Piping, Tubing, and Fittings. Hydronic pipe and tubing shall comply with the applicable standards referenced in Table 1210.1 and shall be approved for use based on the intended purpose. Materials shall be rated for the operating
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HYDRONICS
TABLE 1210.1
MATERIALS FOR HYDRONIC SYSTEM PIPING, TUBING, AND FITTINGS
MATERIAL STANDARDS Col3 MATERIAL PIPING/TUBING FITTINGS Copper/Copper Alloy ASTM B42, ASTM B43, ASTM B75,
ASTM B88, ASTM B135, ASTM B2512,
ASTM B302, ASTM B447ASME B16.15, ASME B16.18, ASME B16.22,
ASME B16.23, ASME B16.24, ASME B16.26,
ASME B16.29, ASME B16.51, ASSE 1061,
ASTM F3226, IAPMO PS 117Ductile Iron AWWA C115/A21.15,
AWWA C151/A21.51AWWA C110/A21.101,
AWWA C153/A21.53Steel ASTM A53, ASTM A106, ASTM A254 ASME B16.5, ASME B16.9,
ASME B16.11, ASTM A420, ASTM F3226,
IAPMO IGC 353, IAPMO PS 117Stainless Steel ASTM A269, ASTM A312,
ASTM A554, ASTM A778ASTM F1476, ASTM F1548, ASTM F3226,
IAPMO IGC 353,CMC § 1220.4.8 High relevance — show source text
1220.4.8 Testing and Flushing. Testing of snow and ice melt systems shall be in accordance with Section 1205.2 and flushing shall be in accordance with Section 1205.3.
1220.5 Hydronic Makeup Air Units. Hydronic makeup air units that are affected by freezing shall be protected against freezing by a hydronic solution.
1221.0 Piping Installation.
1221.1 General. Piping, fittings, and connections shall be installed in accordance with the conditions of their approval and manufacturer’s installation instructions.
1221.2 Embedded Piping Materials and Joints. Piping embedded in concrete shall be steel pipe, Type L copper tubing or plastic pipe or tubing rated at not less than 80 psi at 180°F (552 kPa at 82°C). Joints of pipe or tubing that are embedded in a portion of the building, such as concrete or plaster shall be installed in accordance with Section 1221.2.1 through Section 1221.2.3.
1221.2.1 Steel Pipe. Steel pipe shall be welded by electrical arc or oxygen/acetylene method.
1221.2.2 Copper Tubing. Copper tubing shall be joined by brazing with filler metals having a melting point not less than 1000°F (538°C).
1221.2.3 Plastics. Plastic pipe and tubing shall be installed in continuous lengths or shall be joined by heat fusion methods or other approved fittings in accordance with Table 1210.1 and the manufacturer’s installation instructions. Solvent cement joints shall not be used in embedded applications.
1221.3 Pressure Testing. Piping to be embedded in concrete shall be pressure-tested in accordance with Section 1205.2 prior to pouring concrete. During the pour, the pipe system shall maintain the test pressure of not less than one and one-half times the hydronic system operating pressure and not less than 100 psi (689 kPa). During freezing or the possibility of freezing conditions, testing shall be done with air where permitted by the manufacturer.
1221.4 System Drainage. Hydronic piping systems shall be installed to permit the system to be drained. The system
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1220.4.2 Tube Length. The maximum loop length of continuous tubing from a supply-and-return manifold arrangement shall not exceed the lengths specified by the manufacturer or, in the absence of manufacturer’s specifications, the lengths specified in Table 1220.4.2. Actual loop lengths shall be determined by spacing, flow rate, and pressure drop in accordance with the system design.
1220.4.3 Multizone Systems. In multizone systems, each zone shall have a tag or label securely affixed to the manifold to indicate the length of the loops and the area(s) served.
TABLE 1220.4.2
MAXIMUM LOOP LENGTHS FOR SNOW
AND ICE MELT SYSTEMS [1,2]
CMC § 1406.0 High relevance — show source text
1406.0 Pipe, Tubing, and Fittings.
1406.1 General. Process pipe, tubing, and fittings shall comply with ASME B31.3 and shall be installed in accordance with the manufacturer’s installation instructions. Materials shall be rated for the operating temperatures and pressures of the system, and shall be compatible with the type of liquid.
1406.2 Hazardous Process Piping (HPP). HPP supply piping or tubing in service corridors shall be exposed to view. HPP piping shall be identified in accordance with nationally recognized standards to indicate the material being transported. Liquid HPP piping shall have an approved means for directing spilled materials to an approved containment or drainage system.
Liquid HPP waste or drainage systems shall be installed in accordance with the plumbing code.
1406.2.1 Installation in Exit Corridors and Above Other Occupancies. Hazardous process supply pipe shall not be located within exit corridors, within a portion of a means of egress required to be enclosed in fire-resistive construction, or in concealed spaces in or above
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PROCESS PIPING
areas not classified as Group H Occupancies, except as permitted by this subsection.
Hazardous production material piping and tubing shall be permitted to be installed within the space defined by the walls of exit corridors and the floor or roof above, or in concealed spaces above other occupancies in accordance with Section 1406.2.1.1 through Section 1406.2.1.6.
1406.2.1.1 Automatic Sprinklers. Automatic sprinklers shall be installed within the space unless the space is less than 6 inches (152 mm) in the least dimension.
1406.2.1.2 Ventilation. Ventilation at not less than
6 air changes per hour (ACH) shall be provided. The space shall not be used to convey air from other
areas.
1406.2.1.3 Receptor. Where the piping or tubing is used to transport HPP liquids, a receptor shall be installed below such piping or tubing. The receptor shall be designed to collect discharge or leakage and drain it to an approved location. The 1 hour enclosure shall not be used as part of the receptor.
1406.2.1.4 Separation. HPP supply piping and tubing and HPP nonmetallic waste lines shall be separated from the exit corridor and from an occupancy other than a semi-conductor fabrication facility classified as a Group H Occupancy by construction, as required for walls or partitions that have a fire-protection rating of not less than 1 hour. Where gypsum wallboard is used, joints on the piping side of the enclosure need not be taped, provided the joints occur over framing members. Access openings into the enclosure shall be protected by approved fire assemblies.
1406.2.1.5 Emergency Shutoff Valves. Readily accessible manual or automatic remotely activated fail-safe emergency shutoff valves shall be installed on piping and tubing other than waste lines at the following locations:
(1) At branch connections into the fabrication area.
(2) At entries into exit corridors. Excess flow valves shall be installed as required by the fire code.
CMC § 1211.2.2 High relevance — show source text
1211.2.2 Polyethylene (PE) Plastic Pipe/Tubing. Polyethylene pipe and tubing bends shall have a bend radius in accordance with Table 1211.2.2. When a fitting or flange connection is present in the pipe bend, the minimum bend radius shall be one hundred times the pipe outside diameter (OD) for a distance of five times the pipe diameter on either side of the fitting location.
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1208.2 Mounting. The circulator or pump shall be installed in such a way that strain from the piping is not transferred to the circulator or pump housing. The circulator or pump shall be permitted to be directly connected to the piping, provided the piping is supported on each side of the circulator or pump. Where the installation of a circulator or pump will cause strain on the piping, the circulator or pump shall be installed on a mounting bracket or base plate or securely fastened to or supported by the structure with approved fastening devices. Where means for controlling vibration of a circulator or pump is required, an approved means for support and restraint shall be provided. 1208.3 Sizing. The selection and sizing of a circulator or pump shall be based on all of the following: (1) Loop or system head pressure, feet of head (m) (2) Capacity, gallons per minute (L/s) (3) Maximum and minimum temperature, °F (°C) (4) Maximum working pressure, pounds per square inch (kPa) (5) Fluid type
1209.0 Expansion Tanks. 1209.1 General. An expansion tank shall be installed in each closed hydronic system to control system pressure due to thermal expansion and contraction. Expansion tanks shall be of the closed type. Expansion tanks shall be rated for the pressure of the system. 1209.2 Installation. Expansion tanks shall be accessible for maintenance and shall be installed in accordance with the manufacturer’s installation instructions. Each expansion tank shall be equipped with a shutoff device that will remain open during operation of the hydronic system. Valve handles shall be locked open or removed to prevent from being inadvertently shut off. Provisions shall be made for draining the tank without emptying the system. Expansion tanks shall be securely fastened to or supported by the structure. Supports shall be capable of carrying twice the weight of the tank filled with water without placing a strain on connecting piping. Hot-water-heating systems incorporating hot water tanks or fluid relief columns shall be installed to prevent freezing under normal operating conditions. 1209.3 Closed-Type Tanks. Closed-type expansion tanks shall be designed for a hydrostatic test pressure of two and one-half times the allowable working pressure of the system. Expansion tanks for systems designed to operate at more than 30 pounds-force per square inch (psi) (207 kPa) shall comply with ASME BPVC Section VIII.1.
1209.4 Sizing. Expansion tanks shall be sized to accept the full expansion volume of the fluid in the system. The minimum capacity of a closed-type expansion tank shall be sized in accordance with Section 1004.4.
1210.0 Materials.
1210.1 Piping, Tubing, and Fittings. Hydronic pipe and tubing shall comply with the applicable standards referenced in Table 1210.1 and shall be approved for use based on the intended purpose. Materials shall be rated for the operating
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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 § 1210.0 High relevance — show source text
1210.0 Materials . . . . . . . . . . . . . . . . . . . . 260
1210.1 Piping, Tubing, and Fittings . . . . . 260
1210.2 Expansion and Contraction . . . . . . 260
1210.3 Hangers and Supports . . . . . . . . . 260
1210.4 Oxygen Diffusion Corrosion . . . . . 260
1211.0 Joints and Connections . . . . . . . . 260
1211.1 General. . . . . . . . . . . . . . . . . . . . . 260
1211.2 Pipe Bends . . . . . . . . . . . . . . . . . . 260
Table 1210.1 Materials for Hydronic System Piping, Tubing, and Fittings . . . . . 261
Table 1211.2.2 Minimum Bend Radius
for PE Pipe Installed in Open Cut Trench . . . . . . . . . . . . . 262
1211.3 Chlorinated Polyvinyl Chloride (CPVC) Pipe . . . . . . . . . . . . . . . . . 262
1211.4 CPVC/AL/CPVC Plastic Pipe and Joints . . . . . . . . . . . . . . . . . . . 262
2025 CALIFORNIA MECHANICAL CODE
1211.5 Copper or Copper Alloy Pipe and Tubing . . . . . . . . . . . . . . . . . . 262
1211.6 Crossed-Linked Polyethylene (PEX) Pipe . . . . . . . . . . . . . . . . . . 263
1211.7 Cross-Linked Polyethylene/ Aluminum/Cross-Linked
Polyethylene (PEX-AL-PEX) Pipe. . 263
1211.8 Ductile Iron Pipe . . . . . . . . . . . . . . 263
1211.9 Polyethylene (PE) Plastic Pipe/Tubing. . . . . . . . . . . . 263
1211.10 Polyethylene/Aluminum/ Polyethylene (PE-AL-PE) . . . . . . . 264
1211.11 Polyethylene of Raised Temperature (PE-RT). . . . . . . . . . 264
1211.12 Polypropylene (PP) Pipe. . . . . . . . 264
1211.13 Polyvinyl Chloride (PVC) Pipe . . . 264
1211.14 Steel Pipe and Tubing . . . . . . . . . 265
1211.15 Stainless Steel Pipe and Joints. . . 265
1211.16 Joints Between Various Materials. . 265
1212.0 Valves. . . . . . . . . . . . . . . . . . . . . . 265
1212.1 General. . . . . . . . . . . . . . . . . . . . . 265
1212.2 Where Required . . . . . . . . . . . . . . 265
1212.3 Heat Exchanger . . . . . . . . . . . . . . 265
1212.4 Pressure Vessels . . . . . . . . . . . . . 265
1212.5 Pressure Reducing Valves . . . . . . 265
CMC § 304.8 High relevance — show source text
8
8|20
15
14
12
11|41
31
28
25
23|47
36
33
30
26|85
66
60
53
50|98
75
69
61
57|159
123
112
99
90|186
143
129
117
107|270
217
183
163
147|393
324
283
254
234|621
506
438
390
357|746
611
531
476
434|1330
1090
948
850
777|1480
1210
1050
934
854|For SI units: 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 inch water column = 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.
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FUEL GAS PIPING
TABLE 1315.2(32) CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.3.1(i)]1, Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 2, 3, 4 Col11 Col12 Col13 Col14 Col15 GAS: GAS: GAS: UNDILUTED PROPANE UNDILUTED PROPANE UNDILUTED PROPANE INLET PRESSURE: INLET PRESSURE: INLET PRESSURE: 2.0 psi 2.0 psi 2.0 psi PRESSURE DROP: PRESSURE DROP: PRESSURE DROP: 1.0 psi 1.0 psi 1.0 psi SPECIFIC GRAVITY: SPECIFIC GRAVITY: SPECIFIC GRAVITY: 1.50 1.50 1.50 INTENDED USE: CSST SIZING BETWEEN 2 PSIG SERVICE AND LINE PRESSURE REGULATOR INTENDED USE: CSST SIZING BETWEEN 2 PSIG SERVICE AND LINE PRESSURE REGULATOR **INTENDED USE: CSST SIZING BETWEEN 2 CMC § 1204.8 High relevance — show source text
1204.8 Identification of Chemical Additives. In systems where chemical additives are used, documentation including the following information shall be readily accessible and maintained onsite:
(1) Concentrations
(2) Maintenance requirements
(3) Maintenance log
(4) Material Safety Data Sheet (SDS)
For SI units: 1000 British thermal units per hour = 0.293 kW
1205.0 Installation, Testing, and Inspection.
1205.1 Operating Instructions. Operating and maintenance information shall be provided to the building owner. 1205.2 Pressure Testing. System piping and components shall be tested with a pressure of not less than one and one-half times the operating pressure but not less than 100 psi (689 kPa). Piping shall be tested with water or air except that plastic pipe
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HYDRONICS
shall not be tested with air. Test pressures shall be held for a period of not less than 30 minutes with no perceptible drop in pressure. These tests shall be made in the presence of the Authority Having Jurisdiction.
Exceptions: (1) For PEX, PP-R, PP-RCT, PEX-AL-PEX, PE-RT, and PEAL-PE piping systems, testing with air shall be permitted where authorized by the manufacturer’s instructions for the PEX, PP-R, PP-RCT, PEX-AL-PEX, PE-RT, and PE-ALPE pipe and fittings products, and air testing is not prohibited by applicable codes, laws, or regulations outside this code.
Note: [HCD 1 & HCD 2] PEX-AL-PEX is not adopted in the California Plumbing Code for use in potable water supply and distribution systems. (2) Copper tubing shall be tested at not less than 80 psi (552 kPa). 1205.3 Flushing. Heating and cooling sources, system piping and tubing shall be flushed after installation with water or a cleaning solution. Cleaning and flushing of the heating and cooling sources shall comply with the manufacturer’s instructions. The cleaning solution shall be compatible with all system components and shall be used in accordance with the manufacturer’s instructions.
1206.0 Pressure and Safety Devices. 1206.1 General. Each closed hydronic system shall be protected against pressures exceeding design limitations with not less than one pressure relief valve. Each closed section of the system containing a heat source shall have a relief valve located so that the heat source is not capable of being isolated from a relief device. Pressure relief valves shall be installed in accordance with their listing and the manufacturer’s installation instructions.
1206.2 Discharge Piping. The discharge piping serving a temperature relief valve, pressure relief valve, or combination of both shall have no valves, obstructions, or means of isolation and be provided with the following: (1) Not less than the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down. (2) Materials shall be rated at not less than the operating temperature of the system and approved for such use or shall comply with ASME A112.4.1.
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 § 304.8 High relevance — show source text
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9
8
8|20
15
14
12
11|41
31
28
25
23|47
36
33
30
26|85
66
60
53
50|98
75
69
61
57|159
123
112
99
90|186
143
129
117
107|270
217
183
163
147|393
324
283
254
234|621
506
438
390
357|746
611
531
476
434|1330
1090
948
850
777|1480
1210
1050
934
854|For SI units: 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 inch water column = 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.
266 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
FUEL GAS PIPING
TABLE 1215.2(32) CORRUGATED STAINLESS STEEL TUBING (CSST) [NFPA 54: TABLE 6.3.1(i)]1, Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 , 2, 3, 4 Col11 Col12 Col13 Col14 Col15 GAS: GAS: GAS: UNDILUTED PROPANE UNDILUTED PROPANE UNDILUTED PROPANE INLET PRESSURE: INLET PRESSURE: INLET PRESSURE: 2.0 psi 2.0 psi 2.0 psi PRESSURE DROP: PRESSURE DROP: PRESSURE DROP: 1.0 psi 1.0 psi 1.0 psi SPECIFIC GRAVITY: SPECIFIC GRAVITY: SPECIFIC GRAVITY: 1.50 1.50 1.50 INTENDED USE: CSST SIZING BETWEEN 2 PSIG SERVICE AND LINE PRESSURE REGULATOR INTENDED USE: CSST SIZING BETWEEN 2 PSIG SERVICE AND LINE PRESSURE REGULATOR **INTENDED USE: CSST SIZING BETWEEN CMC § 605.6.2 High relevance — show source text
605.6.2 Mechanical Joints. 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. 605.7 PE-AL-PE Plastic Pipe/Tubing and Joints. PEAL-PE plastic pipe or tubing and fitting joining methods shall be installed in accordance with the manufacturer’s installation instructions and shall comply with Section 605.7.1 and Section 605.7.1.1.
605.7.1 Mechanical Joints. Mechanical joints for PEAL-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. 605.7.1.1 Compression Joints. 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 the pipe. The compression nut and split ring shall be placed around the pipe. The ribbed end of the fitting shall be inserted into the pipe until the pipe contacts the shoulder of the fitting. Position and compress the split ring by tightening the compression nut onto the insert fitting. 605.8 PE-RT. Polyethylene of raised temperature (PE-RT) tubing and fitting joining methods and shall comply with Section 605.8.1.
605.8.1 Mechanical Joints. Fittings for PE-RT tubing shall comply with the applicable standards listed in Table 604.1. Mechanical joints for PE-RT tubing shall be installed in accordance with the manufacturer’s instal lation instructions.
CMC § 304.8 High relevance — show source text
600
14 400| |250
300
400
500|150
136
117
104|202
183
158
140|352
322
279
251|415
379
328
294|679
622
542
488|828
757
657
589|1490
1360
1170
1050|1730
1570
1360
1210|2740
2510
2180
1950|3124
2865
2498
2247|5620
5120
4430
3960|6390
5840
5070
4540|11 200
10 300
8920
8000|12 900
11 700
10 200
9110|For SI units: 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 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 the 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.
268 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
FUEL GAS PIPING
TABLE 1215.2(34) POLYETHYLENE PLASTIC PIPE [NFPA 54: TABLE 6.3.1(k)]* Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 GAS: GAS: ** UNDILUTED PROPANE** ** UNDILUTED PROPANE** INLET PRESSURE: INLET PRESSURE: ** 11.0 in. w.c.** ** 11.0 in. w.c.** PRESSURE DROP: PRESSURE DROP: ** 0.5 in. w.c.** ** 0.5 in. w.c.** SPECIFIC GRAVITY: SPECIFIC GRAVITY: ** 1.50** ** 1.50** **INTENDED USE: PE PIPE SIZING
Frequently asked questions
Can I use regular non‑barrier PEX for a closed hydronic system?
No — PEX used in closed hydronic systems must have an oxygen barrier or the system must be constructed entirely of non‑ferrous or corrosion‑resistant components, per § 1210.4.
Are solvent‑cemented PVC joints allowed for pipe embedded in concrete?
No — solvent cement joints for PVC (or other plastic pipe) are not permitted in embedded applications; embedded plastic piping must be continuous or joined by heat fusion or other approved fittings per § 1221.2.3 and Table 1210.1.
What test pressure must I hold when pressure‑testing piping in a slab?
You must test to not less than one and one‑half times the operating pressure and not less than 100 psi during the pour/test. If that produces two different values, you must meet the higher requirement (the code sets both criteria) — see § 1221.3 and § 1205.2.
Are mechanical compression fittings allowed on PE pipe?
Yes — mechanical insert and compression fittings are permitted when they are listed/approved for that plastic type and installed per the manufacturer’s instructions and the joint rules in § 1211 (see also the PE joint subsections in the code).
Where do I confirm a specific product is acceptable?
Match the product’s listed standards (ASTM, ASME, AWWA, IAPMO, etc.) to those shown for the material in Table 1210.1, and confirm the product is listed/approved for the intended hydronic application per § 1210.1.
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