Ch. 3 General Regulations — 2025 California Mechanical Code
California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-10-19 · California
CBSC: official editions, supplements and errata
Italicized text is a California amendment to the model code, as printed in the official publication.
Cite as: 2025 California Mechanical Code (Title 24, Part 4) Chapter 3 · Effective January 1, 2026 · Official source: Building Standards Commission
(Matrix Adoption Tables are non-regulatory, 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 1 | HCD 2 | HCD 1-AC | DSA AC | DSA SS | DSA SS/CC | OSHPD 1 | OSHPD 1R | OSHPD 2 | OSHPD 3 | OSHPD 4 | OSHPD 5 | OSHPD 6 | BSCC | DPH | AGR | DWR | CEC | CA | SL | SLC |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Adopt Entire Chapter | X | X | X | |||||||||||||||||||||
| Adopt Entire Chapter as amended (amended sections listed below) | X | X | X | X | X | X | X | X | X | |||||||||||||||
| Adopt only those sections that are listed below | X | |||||||||||||||||||||||
| Chapter/ |
||||||||||||||||||||||||
| 301.7 | X | |||||||||||||||||||||||
| 303.2 | † | † | † | † | † | † | ||||||||||||||||||
| 303.7 | X | |||||||||||||||||||||||
| 303.7.1 | X | X | ||||||||||||||||||||||
| 305.2 Exception | X | X | ||||||||||||||||||||||
| 306.2 | X | |||||||||||||||||||||||
| 311.5 | X | |||||||||||||||||||||||
| 316.2 | X | X | ||||||||||||||||||||||
| 316.5 | X | X | ||||||||||||||||||||||
| 316.9 | X | X | ||||||||||||||||||||||
| 318.0 | X | X | X | X | X | X | ||||||||||||||||||
| 319.1 | X | X | X | X | ||||||||||||||||||||
| 319.2 | X | X | ||||||||||||||||||||||
| 320.1 | X | X | X | X | ||||||||||||||||||||
| 320.2 | X | X | ||||||||||||||||||||||
| 320.3 | X | |||||||||||||||||||||||
| 320.4 | X | X | ||||||||||||||||||||||
| 320.5 | X | X | X | X | X | |||||||||||||||||||
| 321.0 | X | X | X | X | X | |||||||||||||||||||
| 322.0 | X | X | X | X | X | |||||||||||||||||||
| 323.0 | X | X | X | X | X | |||||||||||||||||||
| 324.0 | X | X | X | X | X | X | ||||||||||||||||||
| 325.0 | X |
This 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 1.11.0.
CHAPTER 3
GENERAL REGULATIONS
301.0 General.¶
302.0 Materials – Standards and Alternates.¶
303.0 Installation.¶
304.0 Accessibility for Service.¶
305.0 Location.¶
306.0 Automatic Control Devices.¶
307.0 Labeling.¶
308.0 Improper Location.¶
309.0 Workmanship.¶
310.0 Condensate Wastes and Control.¶
311.0 Heating or Cooling Air System.¶
312.0 Plumbing Connections.¶
313.0 Hangers, Supports, and Anchors.¶
314.0 Balancing.¶
315.0 Louvers in Hurricane Prone Regions.¶
316.0 Protection of Piping, Tubing, Materials, and Structures.¶
Structures.
317.0 Trenching, Excavation, and Backfill.¶
318.0 Scope.¶
319.0 Steam and Hot-Water Systems.¶
320.0 Air Conditioning and Heating Systems.¶
321.0 Essential Mechanical Provisions. [OSHPD 1, 2, 3 (Surgical Clinics only) 4 & 5]¶
3 (Surgical Clinics only) 4 & 5] During periods of power outages essential electrical power shall be provided for the following equipment:
323.0 Mechanical Equipment Schedules. [OSHPD 1, 1R, 2, 4 & 5]¶
1R, 2, 4 & 5] Mechanical equipment schedules in the con- struction documents shall clearly indicate which equipment will be powered by essential power and which equipment includes the appropriate special seismic certifications.
324.0 Diesel-Powered Emergency Generators.¶
[OSHPD 1, 1R, 2, 3, 4 & 5] The minimum horizontal sepa- ration distance between diesel-powered emergency electrical generator exhaust outlets and operable doors, windows and intake openings shall be 30 feet (9144 mm). The minimum horizontal distance from the generator exhaust to a property line shall be 15 feet (4572 mm) or per the requirements of the Authority Having Jurisdiction, whichever is greater.
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