Chapter 3 — GENERAL REGULATIONS
306.0 Automatic Control Devices.306.1 General. Heating appliances shall be equipped with a
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.
listed device or devices that will shut off the fuel supply to the main burner or burners in the event of pilot or ignition failure. Liquefied petroleum gas-air-burning heating appliances shall be equipped with a listed automatic device or devices that will shut off the flow of gas to the pilot in the event of ignition failure. Exception: The listed shutoff devices shall not be required on range or cooking tops, log lighters, lights, or other open-burner manually operated appliances, or listed appliances not requiring such devices and specific industrial appliances as approved by the Authority Having Jurisdiction.
Heating appliances whose manual fuel controls are not readily accessible from the main portion of the building being heated shall be equipped with remote controls.
Forced-air and gravity-type warm air furnaces shall be equipped with a listed air outlet temperature limit control that cannot be set for temperatures exceeding 250°F (121°C). Such controls shall be located in the bonnet or plenum, within 2 feet (610 mm) of the discharge side of the heating element of gravity furnaces or in accordance with the conditions of listing.
Electric duct heaters shall be equipped with an approved automatic reset air outlet temperature limit control that will limit the outlet air temperature to not exceed 200°F (93°C). The electric elements of the heater shall be equipped with fusible links or a manual reset temperature limit control that will prevent outlet air temperature in excess of 250°F (121°C).
305.2.1 Coastal High Hazard Areas. Mechanical systems in buildings located in coastal high hazard areas shall be in accordance with the requirements of Section 305.2, and mechanical systems, pipes, and appurtenances shall not be mounted on or penetrate through walls that are intended to breakaway under flood loads in accordance with the building code. 305.2.2 Air Exhaust and Intake Openings. Outside air exhaust openings and air intake openings shall be
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Ask AI about this code▸Contents — 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