CMC · California Mechanical Code

Which industry standards are referenced for process piping design and fabrication?

Summary: For process piping the California Mechanical Code requires following **ASME B31.3**, installing per the manufacturer’s instructions, and using materials rated for the actual operating temperature and pressure and compatible with the liquid being conveyed (see **§ 1406.1**).

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Process piping in the California Mechanical Code must comply with ASME B31.3 and be installed in accordance with the manufacturer’s installation instructions. Materials used for process piping must be rated for the system’s operating temperatures and operating pressures, and must be compatible with the type of liquid being transported. These requirements are stated in § 1406.1.

The single most important rule: Process piping must meet ASME B31.3 and be selected/installed so materials are rated for the actual temperature, pressure and liquid — per § 1406.1.

Requirements in detail

Controlling standard

  • ASME B31.3 — the code explicitly requires process pipe, tubing and fittings to comply with this standard. § 1406.1 is the controlling CMC paragraph.

Installation instructions

  • Installation must follow the manufacturer’s installation instructions. Where an assembly’s safe performance depends on manufacturer guidance (gaskets, flanges, supports, thermal expansion allowances, joining methods, etc.), the CMC requires following those instructions in addition to the referenced standard. § 1406.1.

Materials selection requirements

  • Materials must be:
    • Rated for the operating temperature of the system.
    • Rated for the operating pressure of the system.
    • Compatible with the type of liquid conveyed (chemical compatibility, corrosion resistance, swelling, embrittlement, etc.). These three checks are explicit obligations in § 1406.1.

Decision table — what to check for design and fabrication

Decision item What to look for Code Reference
Applicable design standard ASME B31.3 (Process Piping) — used for design, stress analysis, allowable pressures, joint types and testing procedures § 1406.1
Installation compliance Manufacturer’s installation instructions (joining, supports, torque, clearances, etc.) § 1406.1
Temperature rating Pipe/fitting material and joint ratings (must equal or exceed system operating temperature) § 1406.1
Pressure rating Pressure class or allowable working pressure at system temperature (must equal or exceed system operating pressure) § 1406.1
Chemical compatibility Material compatibility with the liquid (corrosion, embrittlement, seals) § 1406.1

(Every item in the table is required or referenced by § 1406.1. )

Exceptions & special cases

  • The text of § 1406.1 itself states the baseline requirements (ASME B31.3; manufacturer instructions; material ratings). Where a different treatment is required for Hazardous Process Piping (HPP) or special locations, the CMC contains separate, more specific rules (see § 1406.2 and following for HPP location, identification and containment). If your installation involves hazardous liquids or special corridor/egress locations, follow those sections in addition to § 1406.1.

  • If a required detail is not addressed in § 1406.1 (for example specific test pressures, stress-analysis methodology, or exact material allowable stresses), the CMC delegates design detail to the referenced standard ASME B31.3 and to the manufacturer's instructions. The CMC text for § 1406.1 does not list additional numerical thresholds itself.

Common mistakes

  • Relying on generic “plumbing” or “power piping” rules instead of ASME B31.3 for process piping design — the CMC explicitly requires ASME B31.3 for process piping in § 1406.1.
  • Using materials whose ratings are listed at room temperature but not verified for the actual operating temperature — § 1406.1 requires materials be rated for the operating temperature.
  • Selecting fittings or seal materials without checking chemical compatibility with the process liquid — § 1406.1 requires compatibility with the type of liquid.
  • Ignoring manufacturer installation instructions for assemblies (flange gasket type, joint prep, torque, support spacing) — the CMC requires installation per manufacturer instructions. § 1406.1.

Worked example — applying the rule with numbers

Scenario: A laboratory process line will carry a solvent at 180°F (82°C) and 150 psi operating pressure.

  1. Confirm the design standard: use ASME B31.3 for design calculations, allowable stresses, and joining methods as required by § 1406.1.
  2. Select pipe and fittings with manufacturer data showing allowable working pressure ≥ 150 psi at 180°F (manufacturer pressure-temperature table). If the chosen pipe’s allowable pressure at 180°F is only 120 psi, it is insufficient under § 1406.1.
  3. Verify chemical compatibility: confirm the solvent does not attack the chosen material or gaskets (consult chemical compatibility data from the material/fitting manufacturer). § 1406.1 requires compatibility.
  4. Follow the manufacturer’s installation instructions for joining method, torques, supports and testing; do not substitute a different joint procedure unless the manufacturer’s data or ASME B31.3 explicitly permits it. § 1406.1 requires adherence to manufacturer instructions.

If all four checks pass (ASME B31.3 compliance, pressure & temperature rating, chemical compatibility, manufacturer installation), the assembly meets the explicit obligations of § 1406.1.

Related provisions

  • § 1406.2 — Hazardous Process Piping (HPP) location, identification and containment requirements (see for more restrictive rules when piping conveys hazardous liquids).
  • § 1406.2.1 — Installation limitations for HPP in exit corridors and above other occupancies (supplemental rules to § 1406.2).
  • (For fire-code overlap) The California Fire Code and Table 5703.6.2 reference ASME B31.3 for process piping in flammable/combustible liquid systems — consult those sections where fuel/flammable liquids are involved.

Code references

Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:

  • CMC § 12.2 High relevance — show source text

    [12.2] American Petroleum Institute (API), 2001 (Reaffirmed 2007), API Recommended Practice 14C (API RP 14C), “Recommended Practice for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms,” 7th ed., Washington, D.C.

    [12.3] National Fire Protection Association (NFPA), 2012, NFPA 59A, “Standard for the Production, Storage, and Handling of Lique- fied Natural Gas (LNG),” 2013 ed., Quincy, MA.

    [12.4] American Society of Mechanical Engineers (ASME), 2015, ASME B31.3-2014 (ASME B31.3), “Process Piping,” New York.

    [12.5] American Society of Mechanical Engineers (ASME), 2013, ASME B31.5-2013 (ASME B31.5), “Refrigeration Piping and Heat Transfer Components,” New York.

    Authority: Sections 8750 through 8760, Public Resources Code.

    Reference: Sections 8750, 8751, 8755 and 8757, Public Resources Code.

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    CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

    CHAPTER 32 – ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

    Adopting agency BSC BSC-
    CG    		 SFM HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC
    Adopting agency BSC BSC-
    CG    		 SFM 1 2 1/AC AC SS SS/CC 1 1R 2 3 4 5 6 6 6 6 6 6 6 6 6
    Adopt entire chapter X X X X X X X X X
    Adopt entire chapter as
    amended (amended
    sections listed below)
    Adopt only those sections
    that are listed below
    Chapter / Section

    The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

  • 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

    2025 CALIFORNIA MECHANICAL CODE 335

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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 § 3.3.39 High relevance — show source text

    [NFPA 96:3.3.39]

    Plenum. An air compartment or chamber including uninhabited crawl space areas above a ceiling or below a floor, including air spaces below raised floors of computer/data processing centers or attic spaces, to one or more ducts are connected and that forms part of either the supply-air, return-air, or exhaust-air system, other than the occupiable space being conditioned.

    Plumbing Code. The Uniform Plumbing Code (UPC) promulgated by the International Association of Plumbing and Mechanical Officials (IAPMO), as adopted by this jurisdiction. [HCD 1 & HCD 2] Whenever the term “Plumbing Code” is used in this code, it shall mean the California Plumb- ing Code, Title 24, Part 5.

    Portable Cooling Unit. A self-contained refrigerating system, not over 3 horsepower (hp) (2.2 kW) rating that has been factory assembled and tested, installed without supply-air ducts and without connecting any refrigerant-containing parts. This definition shall not include an absorption unit.

    Portable Evaporative Cooler. An evaporative cooler that discharges the conditioned air directly into the conditioned space or zone without the use of ducts and can be readily transported from place to place without dismantling any portion thereof.

    Portable Ventilating Equipment. Ventilating equipment that can be readily transported from place to place without dismantling a portion thereof and that is not connected to a duct.

    2025 CALIFORNIA MECHANICAL CODE 43

    ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

    DEFINITIONS

    Power Boiler Plant. One or more power steam boilers or power hot water boilers and connecting piping and vessels within the same premises.

    Power Ventilator, Dryer Exhaust Duct. A fan used to boost airflow through a clothes dryer duct.

    PP. Polypropylene.

    Pressure, Design. The maximum allowable pressure for which a specific part of a system is designed. Pressure, Design (Refrigeration). The maximum allowable pressure for which a specific part of a refrigeration system is designed.

    Pressure, Field Test. A test performed in the field to prove system tightness.

    Pressure-Imposing Element. A device or portion of the equipment used for the purpose of increasing the pressure of the refrigerant vapor.

    Pressure-Limiting Device. A pressure-responsive mechanism designed to automatically stop the operation of the pressure-imposing element at a predetermined pressure.

    Pressure-Relief Device. A pressure-actuated valve or rupture member or fusible plug designed to automatically relieve excessive pressure.

    Pressure Test. The minimum gauge pressure to which a specific system component is subjected under test condition. Pressure Vessel (Unfired). A closed container, having a nominal internal diameter exceeding 6 inches (152 mm) and a volume exceeding 1 [1] ⁄ 2 cubic feet (0.04 m [3] ), for liquids, gases, vapors subjected to pressures exceeding 15 psi (103 kPa), or steam under a pressure.

    Pressure Vessel, Refrigerant. A refrigerant-containing receptacle that is a portion of a refrigeration system, but shall not include evaporators, headers, or piping of certain limited size and capacity.

  • CMC § 1505.10 High relevance — show source text

    1505.10

    ANSI/SPRI/FM 4435/ES-1—2017: Test Standard for Edge Systems Used with Low Slope Roofing Systems

    1504.6, 1511.7.6.1

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    REFERENCED STANDARDS

    SRCC Solar Rating & Certification Corporation, 400 High Point Drive, Suite 400, Cocoa, FL 32926

    ICC 900/SRCC 300—2020: Solar Thermal System Standard

    3111.2.1

    ICC 901/SRCC 100—2020: Solar Thermal Collector Standard

    3111.2.1

    TIA Telecommunications Industry Association, 1320 N. Courthouse Road #200, Arlington, VA 22201

    ANSI/TIA 222-I—2023: Structural Standard for Antenna Supporting Structures, Antennas and Small Wind Turbine Support

    Structures

    1609.1.1, 3108.1, 3108.2

    TMS The Masonry Society, 105 South Sunset Street, Suite Q, Longmont, CO 80501-6172

    216—2014(19): Code Requirements for Determining Fire Resistance of Concrete and Masonry Construction Assemblies Table 721.1(2), 722.1

    302—2018: Standard Method for Determining the Sound Transmission Ratings for Masonry Assemblies

    1208.2.1

    402—16: Building Code Requirements for Masonry Structures

    2109.1, 2109.1.1, 2109.2

    402—2022: Building Code Requirements for Masonry Structures

    1404.7, 1404.11, 1413.2.2, 1604.3.4, 1705.4, 1807.1.6.3.2, 1808.9, 2101.2, 2101.2.2, 2101A.1.3, 2104A.1.3, 2103.2.4, 2103A.6, 2104A.1.3.10.2, 2106.1, 2106A, 2107.1, 2107.2, 2107.3, 2107.4, 2107A, 2107.5, 2107.6, 2108.1, 2108.2, 2108.3, 2108.4, 2110.1, 2114.1, 2114.4, 2115.1, 2115.2, 2115.5, 2115.6

    403—2017: Direct Design Handbook for Masonry Structures

    2101.2

    404—2023: Standard for the Design of Architectural Cast Stone

    2101.2

    504—2023: Standard for the Fabrication of Architectural Cast Stone

    2103.1

    602—2022: Specification for Masonry Structures

  • CMC § 5703.5.1 High relevance — show source text

    5703.5.1 Style. Warning signs shall be of a durable material. Signs warning of the hazard of flammable liquids shall have white lettering on a red background and shall read: “DANGER—FLAMMABLE LIQUIDS.” Letters shall be not less than 3 inches (76 mm) in height and [1] / 2 inch (12.7 mm) in stroke.

    5703.5.2 Location. Signs shall be posted in locations as required by the fire code official. Piping containing flammable liquids shall be identified in accordance with ASME A13.1.

    5703.5.3 Warning labels. Individual containers, packages and cartons shall be identified, marked, labeled and placarded in accordance with federal regulations and applicable state laws.

    5703.5.4 Identification. Color coding or other approved identification means shall be provided on each loading and unloading riser for flammable or combustible liquids to identify the contents of the tank served by the riser.

    5703.6 Piping systems. Piping systems, and their component parts, for flammable and combustible liquids shall be in accordance with Sections 5703.6.1 through 5703.6.11.

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    FLAMMABLE AND COMBUSTIBLE LIQUIDS

    5703.6.1 Nonapplicability. The provisions of Section 5703.6 shall not apply to gas or oil well installations; piping that is integral to stationary or portable engines, including aircraft, watercraft and motor vehicles; and piping in connection with boilers and pressure vessels regulated by the California Mechanical Code .

    5703.6.2 Design and fabrication of piping systems and components. Piping system components shall be designed and fabricated in accordance with the applicable standard listed in Table 5703.6.2 and Chapter 27 of NFPA 30, except as modified by Section s 5703.6.2.1 and 5703.6.2.2.

    TABLE 5703.6.2—PIPING STANDARDS Col2
    PIPING USE STANDARD
    Power piping ASME B31.1
    Process piping ASME B31.3
    Pipeline transportation systems for liquid hydrocarbons and other liquids ASME B31.4
    Building services piping ASME B31.9
    Double containment piping UL 971A, UL 1369

    5703.6.2.1 Special materials. Low-melting-point materials (such as aluminum, copper or brass), materials that soften on fire exposure (such as nonmetallic materials) and nonductile material (such as cast iron) shall be acceptable for use underground in accordance with the applicable standard listed in Table 5703.6.2. Where such materials are used outdoors in above-ground piping systems or within buildings, they shall be in accordance with the applicable standard listed in Table 5703.6.2 and one of the following:

    1. Suitably protected against fire exposure.
    2. Located where leakage from failure would not unduly expose people or structures.
    3. Located where leakage can be readily controlled by operation of remotely located valves in a location provided with ready access.

    In all cases, nonmetallic piping shall be used in accordance with Section 27.4.6 of NFPA 30.

  • CMC § 31F-85 High relevance — show source text

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    MARINE OIL TERMINALS

    3109F.7 Fire piping and pipeline systems. Firewater and foam piping and fittings shall meet the following requirements: 1. Conform to NFPA 11 [9.13], NFPA 24 [9.14] and ASME B16.5 [9.15] (N/E). 2. Fire mains shall be carbon steel pipe (N/E). 3. High density polyethylene (HDPE) piping may be used for buried pipelines (N/E). 4. Piping and appurtenances shall be color-coded per local jurisdiction requirements or per ASME A13.1 [9.16] (N/E). 5. Pipeline stress analysis shall be performed for firewater piping and pipelines per Section 3109F.3 (N/E). 6. Firewater piping and pipelines supports and attachments shall be assessed per Section 3109F.4. 7. External visual inspection shall be performed per Section 3102F.3.5.3 (N/E).

    3109F.8 References.

    [9.1] American Petroleum Institute (API), 2005, API Standard 2610 (R2010), “Design, Construction, Operation, Maintenance, and Inspection of Terminal and Tank Facilities,” 2 [nd] ed., Washington, D.C.

    [9.2] American Society of Mechanical Engineers (ASME), 2015, ASME B31.3-2014 (ASME B31.3), “Process Piping,” New York.

    [9.3] American Society of Mechanical Engineers (ASME), 2012, ASME B31.4-2012 (ASME B31.4), “Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids,” New York.

    [9.4] California Code of Regulations (CCR), Title 2, Division 3, Chapter 1, Article 5.5 – Marine Terminal Oil Pipelines (2 CCR 2560 et seq.)

    [9.5] American Society of Mechanical Engineers (ASME), 2008, ASME B31E, “Standard for the Seismic Design and Retrofit of Above- Ground Piping Systems,” New York.

    [9.6] American Society of Civil Engineers, 2011, “Guidelines for Seismic Evaluation and Design of Petrochemical Facilities,” 2nd ed., New York.

    [9.7] CalARP Program Seismic Guidance Committee, December 2013, “Guidance for California Accidental Release Prevention (CalARP) Program Seismic Assessments,” Sacramento, CA.

    [9.8] American Petroleum Institute (API), 2009, API Standard 609, “Butterfly Valves: Double Flanged, Lug- and Wafer-Type,” 7th ed., Washington, D.C.

    [9.9] American Society of Mechanical Engineers (ASME), 2013, ASME B16.34-2013 (ASME B16.34), “Valves Flanged Threaded and Welding End,” New York.

    [9.10] American Petroleum Institute (API), 2010, API Standard 607, “Fire Test for Quarter-Turn Valves and Valves Equipped with Nonmetallic Seats,” 6th ed., Washington, D.C.

  • CMC § 608.1.1 High relevance — show source text

    ASHRAE ASHRAE, 180 Technology Parkway, Peachtree Corners, GA 30092

    15—2022: Safety Standard for Refrigeration Systems

    608.1.1, 608.18.3

    170—2021: Ventilation of Health Care Facilities

    1020.6

    ASME American Society of Mechanical Engineers, Two Park Avenue, New York, NY 10016-5990

    A13.1—2020: Scheme for the Identification of Piping Systems

    3509.3, 5003.2.2.1, 5303.4.3, 5503.4.5, 5703.5.2

    A17.1—2022/CSA B44—2022 the edition as referenced in : Safety Code for Elevators and Escalators, California Code of Regulations, Title 8, Division 1, Chapter 4, Subchapter 6, Elevator Safety Orders

    508.1.6, 604.2, 606.2.5, 606.8.6, 606.8.6.1, 606.8.6.2, 606.8.6.3, 606.8.6.4, 907.3.3, 1009.4.1, 1103.3.3

    A17.3—2023: Safety Code for Existing Elevators and Escalators California Code of Regulations, Title 8, Division 1, Chapter 4, Subchapter 6, Elevator Safety Orders

    1103.3.1, 1103.3.2

    B16.18—2023: Cast Copper Alloy Solder Joint Pressure Fittings

    909.13.1

    B16.22—2023: Wrought Copper and Copper Alloy Solder-Joint Pressure Fittings

    909.13.1

    B31.1—2022: Power Piping 5003.2.2, Table 5703.6.2

    B31.3—2022: Process Piping 5003.2.2.2, Table 5703.6.2

    B31.4—2022: Pipeline Transportation Systems for Liquids and Slurries

    Table 5703.6.2

    B31.9—2023: Building Services Piping Table 5703.6.2, 5703.6.3, 5703.6.11

    BPE—2009: Bioprocessing Equipment Standard

    BPVC—2023: ASME Boiler & Pressure Vessel Code (Sections I, II, IV, V, VI and VIII)

    5003.2.1, 5303.2, 5303.3.2, 5503.2.6, 5503.4.3, 5503.7, 5704.2.13.1.5, 5806.3.1, 5806.4.1, 5806.4.8

    ASSP American Society of Safety Professionals, 520 N. Northwest Highway, Park Ridge, IL 60068

    ANSI/ASSP Z359.1—2020: The Fall Protection Code

    1015.6, 1015.7

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    REFERENCED STANDARDS

  • CMC § 9.3 High relevance — show source text

    [9.3] American Society of Mechanical Engineers (ASME), 2012, ASME B31.4-2012 (ASME B31.4), “Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids,” New York.

    [9.4] California Code of Regulations (CCR), Title 2, Division 3, Chapter 1, Article 5.5 – Marine Terminal Oil Pipelines (2 CCR 2560 et seq.)

    [9.5] American Society of Mechanical Engineers (ASME), 2008, ASME B31E, “Standard for the Seismic Design and Retrofit of Above- Ground Piping Systems,” New York.

    [9.6] American Society of Civil Engineers, 2011, “Guidelines for Seismic Evaluation and Design of Petrochemical Facilities,” 2nd ed., New York.

    [9.7] CalARP Program Seismic Guidance Committee, December 2013, “Guidance for California Accidental Release Prevention (CalARP) Program Seismic Assessments,” Sacramento, CA.

    [9.8] American Petroleum Institute (API), 2009, API Standard 609, “Butterfly Valves: Double Flanged, Lug- and Wafer-Type,” 7th ed., Washington, D.C.

    [9.9] American Society of Mechanical Engineers (ASME), 2013, ASME B16.34-2013 (ASME B16.34), “Valves Flanged Threaded and Welding End,” New York.

    [9.10] American Petroleum Institute (API), 2010, API Standard 607, “Fire Test for Quarter-Turn Valves and Valves Equipped with Nonmetallic Seats,” 6th ed., Washington, D.C.

    [9.11] American Petroleum Institute (API), API Recommended Practice 520 P1 and P2 (API 520), “Sizing, Selection, and Installation of Pressure-relieving Devices, Part 1 —Sizing and Selection,” 2014, 9th ed., and “Sizing, Selection, and Installation of Pressure- Relieving Devices in Refineries – Part 2 – Installation,” 2015, 6th ed., Washington, D.C.

    [9.12] Code of Federal Regulations (CFR), Title 33, Section 154.2100 – Vapor Control System, General (33 CFR 154.2100)

    [9.13] National Fire Protection Association (NFPA), NFPA 11, “Standard for Low-, Medium-, and High-Expansion Foam,” Quincy, MA. For edition, see California Code of Regulations (CCR), Title 24, Part 2, Chapter 35 – Referenced Standards.

    [9.14] National Fire Protection Association (NFPA), NFPA 24, “Standard for the Installation of Private Fire Service Mains and Their Appurtenances,” Quincy, MA. For edition, see California Code of Regulations (CCR), Title 24, Part 2, Chapter 35 – Referenced Standards.

    [9.15] American Society of Mechanical Engineers (ASME), 2013, ASME B16.5-2013 (ASME B16.5), “Pipe Flanges and Flanged Fittings,” New York.

    [9.16] American Society of Mechanical Engineers (ASME), 2007, ASME A13.1-2007 (R2013) (ASME A13.1), “Scheme for the Identification of Piping Systems,” New York.

    Authority: Sections 8750 through 8760, Public Resources Code.

  • CMC § 301.2.4 High relevance — show source text

    Waste, and Vent Piping Applications|Piping, Ferrous|301.2.4, Table 701.2,
    Table 707.2| |CISPI 310-2020|Couplings for Use in Connection with Hubless Cast Iron Soil
    Pipe and Fittings for Sanitary and Storm Drain, Waste, and
    Vent Piping Applications|Joints|301.2.4, 705.2.2| |CSA|CSA|CSA|CSA| |ASME A112.19.2-
    2018/CSA B45.1-2018|Ceramic Plumbing Fixtures|Fixtures|407.1, 408.1, 409.1,
    410.1, 411.1, 412.1,
    415.1, 420.1| |ASME A112.19.1-
    2018/CSA B45.2-2018|Enameled Cast Iron and Enameled Steel Plumbing Fixtures|Fixtures|407.1, 408.1, 409.1,
    415.1, 420.1| |ASME A112.19.3-
    2017/CSA B45.4-2017|Stainless Steel Plumbing Fixtures|Fixtures|407.1, 408.1, 409.1,
    410.1, 411.1, 415.1,
    420.1| |CSA B45.5-2017/IAPMO
    Z124-2017|Plastic Plumbing Fixtures (with Errata dated August 2017)|Fixtures|407.1, 408.1, 409.1,
    411.1, 412.1, 420.1| |CSA B45.8-2018/IAPMO
    Z403-2018|Terrazzo, Concrete, Composite Stone, and Natural Stone
    Plumbing Fixtures|Fixtures|407.1, 420.1| |ASME A112.3.4-2018/CSA
    B45.9-2018|Macerating Toilet Systems and Waste-Pumping Systems for
    Plumbing Fixtures|Fixtures|710.13| |ASME A112.19.7-
    2020/CSA B45.10-2020|Hydromassage Bathtub Systems|Fixtures|409.1, 409.6.1|

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    REFERENCED STANDARDS

    TABLE 1701.1 (continued) REFERENCED STANDARDS

    STANDARD NUMBER STANDARD TITLE APPLICATION REFERENCED
    SECTION
    CSA B45.11-2017/IAPMO
    Z401-2017 (R2021)    		 Glass Plumbing Fixtures Fixtures 407.1
    CSA B45.12-2013/IAPMO
    Z402-2013 (R2018)    		 Aluminum and Copper Plumbing Fixtures Fixtures 407.1, 408.1, 409.1,
    420.1
    ASME A112.19.5-
    2017/CSA B45.15-2017    		 Flush Valves and Spuds for Water Closets, Urinals, and Tanks Fixtures 413.3
    ASME A112.4.
  • CMC § 3-2020 High relevance — show source text

    3-2020|Process Piping|Piping|1308.2(9)| |ASME B36.10M-2018|Welded and Seamless Wrought Steel Pipe|Fuel Gas, Piping|1208.5.2.2| |ASME BPVC Section
    VIII.1-2021|Rules for Construction of Pressure Vessels - Division 1|Miscellaneous|505.4, 1309.5(2),
    1310.4(2), 1312.3(2)| |ASME BPVC Section IX-
    2021|Welding, Brazing, and Fusing Qualifications - Qualification
    Standard for Welding, Brazing, and Fusing Procedures;
    Welders; Brazers; and Welding, Brazing, and Fusing Operators|Miscellaneous|1322.1.1, 1322.2.1,
    1323.11| |ASPE|ASPE|ASPE|ASPE| |ASPE/ANSI 45-2018|Siphonic Roof Drainage|Storm Drainage|1106.2| |ARCSA/ASPE/ANSI 63-
    2020|Rainwater Catchment Systems|Miscellaneous|1602.1| |ASSE|ASSE|ASSE|ASSE| |ASSE 1001-2017|Atmospheric Type Vacuum Breakers|Backflow Protection|Table 603.2| |ASSE 1002-2020/ASME
    A112.1002-2020/CSA
    B125.12-2020|Anti-Siphon Fill Valves for Water Closet Tanks|Backflow Protection|413.3, Table 603.2| |ASSE 1003-2020e2|Water Pressure Reducing Valves for Potable Water Distribution
    Systems|Valves|608.2| |ASSE 1004-2017|Commercial Dishwashing Machines|Backflow Protection|414.2| |ASSE 1008-2020|Plumbing Aspects of Residential Food Waste Disposer Units|Appliances|419.1| |ASSE 1010-2004|Water Hammer Arresters|Appliances|609.11| |ASSE 1011-2017|Hose Connection Vacuum Breakers|Backflow Protection|Table 603.2|

    2025 CALIFORNIA PLUMBING CODE 337

    ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

    REFERENCED STANDARDS

    TABLE 1701.1 (continued) REFERENCED STANDARDS

    STANDARD NUMBER STANDARD TITLE APPLICATION REFERENCED
    SECTION
    ASSE 1012-2009 Backflow Preventers with an Intermediate Atmospheric Vent Backflow Protection Table 603.2
    ASSE 1013-2021 Reduced Pressure Principle Backflow Prevention Assemblies Backflow Protection Table 603.2
    ASSE 1014-2020 Backflow Prevention Devices for Hand-Held Showers Backflow Protection 417.3
    ASSE 1015-2021 Double Check Backflow Prevention Backflow Protection Table 603.2
    ASSE 1016-2017/ASME
    A112.1016-2017/CSA
    B125.
  • CMC § 4.3 High relevance — show source text

    4.3-1999
    (R2019)|Plastic Fittings for Connecting Water Closets to the Sanitary Drainage System|Fittings| |ASME A112.19.10-2017|Retrofit Dual Flush Devices for Water Closets|Fixtures| |ASME A112.21.3M-1985
    (R2017)|Hydrants for Utility and Maintenance Use|Valves| |ASME B1.20.3-1976
    (R2018)|Dryseal Pipe Threads (Inch)|Joints| |ASME B16.39-2019|Malleable Iron Threaded Pipe Unions: Classes 150, 250 and 300|Fittings| |ASME B16.40-2019|Manually Operated Thermoplastic Gas Shutoffs and Valves in Gas Distribution Sys-
    tems|Valves| |ASME B31.1-2020|Power Piping|Piping| |ASME B36.19M-2018|Stainless Steel Pipe|Piping, Ferrous| |ASME BPVC Section IV-
    2021|Rules for Construction of Heating Boilers|Miscellaneous| |ASPE|ASPE|ASPE| |ARCSA/ASPE 78-2015|Stormwater Harvesting System Design for Direct End-Use Applications|Miscellaneous| |WQA/ASPE/ANSI S-803-
    2017|Sustainable Drinking Water Treatment Systems|Miscellaneous| |ASSE|ASSE|ASSE| |ASSE 1017-2009|Temperature Actuated Mixing Valves for Hot Water Distribution Systems|Valves| |ASSE 1066-1997|Individual Pressure Balancing In-Line Valves for Individual Fixture Fittings|Valves| |ASSE 1082-2018|Water Heaters with Integral Temperature Control Devices for Hot Water Distribution
    Systems|Appliances| |ASSE 1086-2020|Reverse Osmosis Water Efficiency – Drinking Water|Appliances| |ASSE/IAPMO/ANSI 5110-
    2015|Backflow Prevention Assembly Testers|Professional
    Qualifications|

    352 2025 CALIFORNIA PLUMBING CODE

    ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

    REFERENCED STANDARDS

    TABLE 1701.2 (continued) STANDARDS, PUBLICATIONS, PRACTICES, AND GUIDES

    DOCUMENT NUMBER DOCUMENT TITLE APPLICATION
    ASSE/IAPMO/ANSI 5120-
    2015    		 Cross-Connection Control Surveyors Professional
    Qualifications
    ASSE/IAPMO/ANSI 5130-
    2015    		 Backflow Prevention Assembly Repairers Professional
    Qualifications
    ASSE/IAPMO/ANSI 5140-
    2015    		 Fire Protection System Cross-Connection Control Tester Professional
    Qualifications
    ASSE/IAPMO/ANSI 5150-
    2015    		 Backflow Prevention Program Administrators Professional
    Qualifications
    ASSE/IAPMO/ANSI Series
    6000-2021    		 Professional Qualifications Standard for Medical Gas Systems Personnel Professional
    Qualifications
    ASSE/IAPMO/ANSI 6015-
    2021    		 Bulk Medical Gas/Cryogenic Fluid Central Supply Systems Installers Professional
    Qualifications
    ASSE/IAPMO/ANSI
  • CMC § 16000-2019 High relevance — show source text

    Series
    16000-2019|Professional Qualifications Standard for Inspectors and Plans Examiners|Professional Qualifications| |ASSE/IAPMO/ANSI 16020-
    2019|Professional Qualifications Standard for the Mechanical Inspector|Professional Qualifications|

    2025 CALIFORNIA MECHANICAL CODE 379

    ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

    REFERENCED STANDARDS

    » TABLE 1801.2 (continued) STANDARDS, PUBLICATIONS, PRACTICES, AND GUIDES

    DOCUMENT NUMBER DOCUMENT TITLE APPLICATION
    ASSE/IAPMO/ANSI 16050-
    2019    		 Professional Qualifications Standard for the Mechanical Plan Examiner Professional Qualifications
    ASSE/IAPMO/ANSI Series
    19000-2015 (R2020)    		 Hydronic Systems Professional Qualifications Standard Professional Qualifications
    ASSE/IAPMO/ANSI 19110-
    2015 (R2020)    		 Professional Qualifications Standard for the Solar Water Heating System
    Installer    		 Professional Qualifications
    ASSE/IAPMO/ANSI 19210-
    2015 (R2020)    		 Professional Qualifications Standard for the Hydronic Heating and Cooling
    System Installer    		 Professional Qualifications
    ASSE/IAPMO/ANSI 19220-
    2015 (R2020)    		 Professional Qualifications Standard for the Hydronic Heating and Cooling
    System Designer    		 Professional Qualifications
    ASTM ASTM ASTM
    ASTM A568/A568M-2019a Standard Specification for Steel, Sheet, Carbon, Structural, and High-Strength,
    Low-Alloy, Hot-Rolled and Cold-Rolled, General Requirements for    		 Piping
    ASTM A653/A653M-2020 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron
    Alloy-Coated (Galvannealed) by the Hot-Dip Process    		 Piping, Ferrous
    ASTM A733-2016 Standard Specification for Welded and Seamless Carbon Steel and Austenitic
    Stainless Steel Pipe Nipples    		 Piping, Ferrous
    ASTM B370-2012 (R2019) Standard Specification for Copper Sheet and Strip for Building Construction Miscellaneous
    ASTM B687-1999 (R2016) Standard Specification for Brass, Copper, and Chromium-Plated Pipe Nipples Piping, Copper Alloy
    ASTM C518-2021 Standard Test Method for Steady-State Thermal Transmission Properties by
    Means of the Heat Flow Meter Apparatus    		 Certification: Calibration,
    Error Analysis, Heat Flow
    Meter Apparatus, Heat
    Flux, Instrument Verifica-
    tion, Thermal Conductiv-
    ity, Thermal Resistance,
    Thermal Testing, Tunnel
    Test
    ASTM D93-2020 Standard Test Method for Flash Point by Pensky-Martens Closed Cup Tester Certification
    ASTM D396-2021 Standard Specification for Fuel Oils Boiler
    ASTM D2517-2018 Standard Specification for Reinforced Epoxy Resin Gas Pressure Pipe and Fit-
    tings    		 Piping,

Frequently asked questions

What single standard must process piping comply with under the CMC?

Process piping must comply with ASME B31.3 as required by § 1406.1.

Do I still need to follow the manufacturer’s instructions?

Yes — § 1406.1 requires installation in accordance with the manufacturer’s installation instructions.

Does the CMC give specific temperature/pressure numbers for process piping materials?

No — § 1406.1 requires that materials be rated for the system’s operating temperature and pressure, but it does not list specific numeric thresholds; those are determined by system design and the referenced standard ASME B31.3 and manufacturer data.

If my piping carries a hazardous liquid, is § 1406.1 enough?

No — hazardous process piping is subject to additional rules in § 1406.2 and following; you must follow those sections in addition to § 1406.1.

Can I use a different ASME B31 series code (B31.1, B31.9) instead of B31.3?

Not for process piping covered by § 1406.1 — the CMC explicitly requires ASME B31.3 for process piping; other B31 codes apply to other piping categories.

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