Chapter 3 — GENERAL REGULATIONS
321.2 All heating equipment necessary to maintain the min-
California Mechanical Code (Title 24, Part 4) · 2019 edition · updated 2026-09-10 · California
Italicized text is a California amendment to the model code, as printed in the official publication.
imum temperatures listed in Table 4-A for sensitive areas specified in Section 322.0.
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Ask AI about this code▸Contents — California Mechanical Code (Title 24, Part 4)
California Mechanical Code (Title 24, Part 4)
- Chapter 1 — GENERAL CODE PROVISIONS
- Chapter 2 — DEFINITIONS
▸Chapter 3 — GENERAL REGULATIONS
Overview- 301.2 Approval. Equipment or appliance shall be approved
- 301.3 Design of Equipment. Installers shall furnish satisfacto…
- 301.4 Electrical Connections. For equipment regulated
- 301.5 Oil-Burning Appliances. The tank, piping, and
- 301.6 Personnel Protection. A metal guard shall be provided ar…
- 302.0 Materials – Standards and Alternates.302.1 Minimum Stand…
- 302.2 Alternate Materials and Methods of Construc-tion Equival…
- 302.3 Alternative Engineered Design. An alternative
- 303.2 Closet or Alcove Installations. Central heating
- 303.3 Unlisted Appliances. Except as otherwise permitted in th…
- 303.4 Anchorage of Appliances. Appliances designed to
- 303.5 Movement. Movement of appliances with casters
- 303.6 Identification of Equipment. Where more than one
- 303.7 Liquefied Petroleum Gas Facilities. Containers,
- 303.8 Appliances on Roofs. Appliances on roofs shall be
- 303.9 Avoiding Strain on Gas Piping. Appliances shall
- 303.10 Clearances. Appliances and their vent connectors
- 303.11 Installation in Commercial Garages. Appliances installe…
- 303.12 Installation in Aircraft Hangars. Heaters in aircraft h…
- 303.13 Pit Location. Where excavation is necessary to install
- 304.1 General.304.0 Accessibility for Service. Appliances shal…
- 304.2 Sloped Roof. Where equipment or appliances that
- 304.3 Access to Appliances on Roofs. Appliances
- 304.4 Appliances in Attics and Under-Floor Spaces.
- 305.3 Elevator Shaft. Unless required for the functionality
- 305.4 Drainage Pan. Where a water heater is located in an
- 305.0 Location.305.1 Installation in Garages. Appliances in re…
- 305.2 Flood Hazard Areas. For buildings located in flood
- 306.0 Automatic Control Devices.306.1 General. Heating applian…
- 307.0 Labeling.307.1 Fuel-Burning Appliances. Fuel-burning hea…
- 307.2 Electric Heating Appliances. Electric heating
- 307.3 Heat Pump and Electric Cooling Appliances.
- 307.4 Absorption Units. Absorption units shall bear a permanen…
- 309.2 Concealing Imperfections. It shall be unlawful to
- 309.3 Installation Practices. Mechanical systems shall
- 310.0 Condensate Wastes and Control.310.1 Condensate Disposal.…
- 310.2 Condensate Control. Where an equipment or appliance is i…
- 310.4 Appliance Condensate Drains. Condensate drain
- 310.5 Point of Discharge. Air-conditioning condensate
- 310.6 Condensate Waste From Air-ConditioningCoils. Where the c…
- 310.7 Plastic Fittings. Female plastic screwed fittings shall
- 310.3 Condensate Waste Pipe Material and Sizing.
- 311.2 Air Filters. Air filters shall be installed in a heating,
- 311.3 Prohibited Source. Outside or return air for a heating
- 313.2 Material. Hangers and anchors shall be of sufficient
- 313.3 Suspended Piping. Suspended piping or tubing
- 313.4 Alignment. Piping or tubing shall be supported in such
- 313.5 Underground Installation. Piping or tubing in the
- 313.6 Hanger Rod Sizes. Hanger rod sizes shall be not
- 313.7 Gas Piping. Gas piping shall be supported by metal
- 314.0 Balancing.314.1 General. Heating, ventilating, and air-c…
- 311.4 Return-Air Limitations. Return air from one dwelling
- 315.0 Louvers in Hurricane Prone Regions.315.1 General. Louver…
- 316.2 Installation. Piping or tubing shall be installed so that
- 316.3 Corrosion, Erosion, and Mechanical Damage. Piping or tub…
- 316.4 Protectively Coated Pipe. Protectively coated pipe
- 316.5 Fire-Resistant Construction. Piping, tubing, and
- 316.6 Steel Nail Plates. Plastic piping or tubing, copper
- 316.7 Sleeves. Sleeves shall be provided to protect piping
- 316.8 Firewalls. A pipe sleeve through a firewall shall have
- 316.9 Structural Members. A structural member weakened or impa…
- 316.10 Rodentproofing. Mechanical system shall be constructed …
- 316.11 Metal Collars. In or on buildings where openings
- 317.1 Trenches. 317.0 Trenching, Excavation, and Backfill. Tre…
- 317.2 Tunneling and Driving. Tunneling and driving shall
- 317.3 Open Trenches. Excavations required to be made for
- 317.4 Excavations. Excavations shall be completely backfilled …
- 318.2 Services/Systems and Utilities. Refer to Section
- 319.1 Requirements for Hospitals and Optional Serv-
- 319.2 Requirements for Skilled Nursing, Intermedi-
- 320.1 Requirements for Hospitals and Optional Serv-
- 320.2 Requirements for Skilled Nursing, Intermedi-
- 320.3 Requirements for Outpatient Facilities and
- 320.5 Psychiatric Services. [OSHPD 1, 1R, 2, 4 & 5 ] For proje…
- 321.1 (Does not apply to OSHPD 3 surgical clinic.) All heat-
- 321.2 All heating equipment necessary to maintain the min-
- 321.3 Equipment necessary for humidification of the areas
- 321.4 All supply, return, and exhaust fans required to maintain
- 321.5 All control components and control systems necessary
- 321.6 Alarms for airborne infection isolation rooms and pro-
- 322.1 The following conditions shall be met for sensitive
- Chapter 4 — VENTILATION AIR
- Chapter 5 — EXHAUST SYSTEMS
- Chapter 6 — DUCT SYSTEMS
- Chapter 7 — COMBUSTION AIR
- Chapter 8 — CHIMNEYS AND VENTS
- Chapter 9 — INSTALLATION OF SPECIFIC APPLIANCES
- Chapter 10 — BOILERS AND PRESSURE VESSELS
- Chapter 11 — REFRIGERATION
- Chapter 12 — HYDRONICS
- Chapter 13 — FUEL GAS PIPING
- Chapter 14 — PROCESS PIPING
- Chapter 15 — SOLAR ENERGY SYSTEMS
- Chapter 16 — STATIONARY POWER PLANTS
- Chapter 17 — REFERENCED STANDARDS
- Appendix A — RESIDENTIAL PLAN EXAMINER REVIEW FORM FOR HVAC SY…
- Appendix B — PROCEDURES TO BE FOLLOWED TO PLACE GAS EQUIPMENT …
- Appendix C — INSTALLATION AND TESTING OF OIL (LIQUID) FUEL-FIR…
- Appendix D — FUEL SUPPLY: MANUFACTURED/MOBILE HOME PARKS AND R…
- Appendix E — SUSTAINABLE PRACTICES
- Appendix F — SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION …
- Appendix G — EXAMPLE CALCULATION OF OUTDOOR AIR RATE