217.0 – O –
California Mechanical Code (Title 24, Part 4) · 2022 edition · updated 2026-09-10 · California
Italicized text is a California amendment to the model code, as printed in the official publication.
Occupancy. The purpose for which a building or part thereof is used or intended to be used. Occupancy, Nontransient. Occupancy of a dwelling unit or sleeping unit for more than 30 days. [ASHRAE 62.1:3] Occupancy Classification. Classifications are defined in the building code. [HCD 1, HCD 2 & SFM] Whenever the term “Building Code” is used in this code, it shall mean the California Building Code, Title 24, Part 2. Occupational Exposure Limit (OEL). The timeweighted average (TWA) concentration for a normal 8-hour workday and a 40-hour workweek to which nearly all workers can be repeatedly exposed without adverse effect, based on the OSHA PEL, ACGIH TLV-TWA, TERA OARSWEEL, or consistent value. [ASHRAE 34:3] Occupiable Space. An enclosed space intended for human activities, excluding spaces that are intended to be occupied occasionally and for short periods of time, such as storage rooms, equipment rooms, and emergency exitways.
[ASHRAE 62.1:3] Open Combustible Construction. Combustible building construction, including wall, structural framing, roof, roof ceiling, floor, and floor-ceiling assemblies, adjacent to a grease duct on three or fewer sides where one or more sides require protection in accordance with Section 507.4.
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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
Overview- 201.1 Applicability. For the purpose of this code, the followi…
- 202.1 General. The definitions of terms are arranged alphabeti…
- 203.0 – A –
- 204.0 – B –
- 205.0 – C –
- 206.0 – D –
- 207.0 – E –
- 208.0 – F –
- 209.0 – G –
- 210.0 – H –
- 211.0 – I –
- 212.0 – J –
- 214.0 – L –
- 215.0 – M –
- 216.0 – N –
- 217.0 – O –
- 218.0 – P –
- 220.0 – R –
- 221.0 – S –
- 222.0 – T –
- 223.0 – U –
- 224.0 – V –
- 228.0 – Z –
- Chapter 3 — GENERAL REGULATIONS
- 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 — GEOTHERMAL ENERGY SYSTEMS
- Appendix G — SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION …
- Appendix H — EXAMPLE CALCULATION OF OUTDOOR AIR RATE