CMC · California Mechanical Code

Are CMC appendices mandatory or optional?

Appendices in the California Mechanical Code are optional guidance unless a state agency or a local jurisdiction formally adopts them; check **§ 1.1.4** and your local building department or ordinance to know whether a particular appendix is mandatory where your project is located.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Short answer: Appendices in the California Mechanical Code are not mandatory unless an adopting authority makes them so. The California Mechanical Code states this rule in § 1.1.4: “Provisions contained in the appendices of this code shall not apply unless specifically adopted by a state agency or adopted by a local enforcing agency …” § 1.1.4 . The same general approach appears in the California Building Code as § 101.2.1: “Provisions in the appendices shall not apply unless specifically adopted.” § 101.2.1 .

The single most important rule: appendices are voluntary by default — they only become mandatory if a state agency or local jurisdiction adopts them under the procedures the code references.

Requirements in detail

Governing rule (plain-English)

The CMC makes appendices supplemental material. They do not become enforceable automatically for projects in a city/county or for most state-regulated applications. See § 1.1.4 for the controlling statement. § 1.1.4 .
When a state agency chooses to adopt an appendix (or when a local enforcing agency adopts it by ordinance), the appendix becomes part of the enforceable standards for that agency’s jurisdiction. See § 1.1.4 and related adoption/matrix references in the CMC. § 1.1.4 .

Decision‑relevant dimensions (quick reference table)

Decision question	Possible values	What it means	Code Reference
Are appendices automatically enforceable?	No / Yes	Default = No; only enforceable if adopted	§ 1.1.4
Who can make an appendix mandatory?	State agency, local enforcing agency	Either can adopt appendices for their scope (state agencies by their adoption authority; cities/counties by ordinance)	§ 1.1.4
Procedure to check adoption status	Check local ordinance / agency adoption matrix	Adoption is shown in local code amendments or the code’s matrix tables (adoption matrices indicate which chapters/appendices are adopted for specific agencies)	CMC matrix and adoption notes (see CMC appendices & matrix)
If adopted, who must comply?	Projects within the adopting authority’s jurisdiction	Once adopted, the appendix becomes an enforceable requirement for permits and inspections in that jurisdiction	§ 1.1.4
Examples of appendix content	Procedures, forms, examples, voluntary measures	Appendices often include guidance (e.g., sustainable practices, sizing examples) intended to supplement the main code	CMC Appendix list (Appendix E, F, etc.)

What “adopted” means (process)

“Adopted” typically means the adopting authority has formally incorporated the appendix into its enforceable code — for cities/counties this is done by ordinance or resolution; for state agencies it is done through the agency’s adoption process. The Green Building Standards Code shows sample adoption language and a sample resolution for adopting appendices as mandatory by local ordinance (useful as an example).
The CMC includes matrix/adoption tables and front-matter notes to show which jurisdictions or state agencies have adopted particular parts of the code or appendices; consult those tables to determine current applicability in a specific agency’s authority.

Exceptions & special cases

State-agency adoption: If a state agency (e.g., Department of Housing and Community Development in its scope) adopts an appendix for the facilities it regulates, that appendix is mandatory for projects regulated by that agency. See § 1.1.4 .
Local adoption only: A city or county may choose to adopt one or more appendices (in whole or with amendments) by local ordinance; an appendix adopted locally applies only inside that local jurisdiction. Example adoption language and a sample local resolution appear in the Green Building Standards Code appendices.
Matrix/adoption variability: The CMC is adopted chapter‑by‑chapter in some contexts and has adoption matrices that show which agencies adopt which portions. That means appendix adoption can vary by agency (and sometimes by chapter/appendix). Check the code’s matrix tables and the enforcing agency’s local code amendments.
“Referenced” appendices: In some cases a body of the code or a referenced standard may incorporate appendix content by reference; if that occurs the referenced content may become enforceable — verify by reading the specific adopting language and referenced sections. See CMC references and matrix notes.

Common mistakes

Mistake: Assuming appendices are enforceable statewide by default. Why wrong: the CMC makes them non‑mandatory unless adopted. See § 1.1.4.
Mistake: Relying on a printed copy of the code without checking local amendments. Why wrong: a local jurisdiction may have adopted an appendix (or an amended version) by ordinance — always check the local code or the enforcing agency. See the CMC’s matrix/adoption notes.
Mistake: Treating a model-code appendix as a “guideline only” even after local adoption. Why wrong: once the appendix is adopted, it is enforceable like any other code provision for that jurisdiction. See § 1.1.4.

Worked example — concrete scenario

Scenario: City of Oakfield is considering whether Appendix E (Sustainable Practices) of the CMC applies to a new HVAC permit.

Default: Appendix E is not mandatory statewide — appendices are non‑mandatory unless adopted. § 1.1.4 .
Check local adoption: Oakfield passed Ordinance 2026‑12 on 2026‑01‑15 specifically adopting Appendix E as part of the city’s mechanical code. Because Oakfield’s ordinance explicitly adopts Appendix E, Appendix E is now mandatory for projects with permit applications filed in Oakfield after the ordinance effective date.
Permit result: An HVAC contractor files for a permit on 2026‑03‑01 in Oakfield. The building department will enforce Appendix E requirements for that permit because the city adopted the appendix by ordinance — the appendix is now part of the enforceable local code in Oakfield. See § 1.1.4 and the sample local adoption approach illustrated in the Green Building Standards Code materials.

Practical check: before designing or permitting, always (a) ask the local building department whether any appendices are adopted locally and (b) inspect the jurisdiction’s amendment/adoption ordinance or the code adoption matrix the department uses. The CMC’s front‑matter and matrix notes point to where adoption status is shown.

Related provisions

§ 1.1.4 — Appendices (CMC: appendices not mandatory unless adopted)
§ 1.1.5 — Referenced codes (how referenced standards interact with code requirements)
§ 1.1.7 — Order of precedence and use (specific vs. general provisions)
§ 101.2.1 — Appendices (California Building Code — parallel statement that appendices do not apply unless adopted)
Matrix/adoption notes and tables — used to determine which state agencies adopted which chapters/appendices (see CMC matrix tables)

Code references

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

CMC § 101.4 Medium relevance — show source text
When adopted by a state agency, the provisions of this code shall be enforced by the appropriate enforcing agency, but only to the extent of authority granted to such agency by statute.
1. State-owned buildings, including buildings constructed by the Trustees of the California State University, and to the extent permitted by California law, buildings designed and constructed by the Regents of the University of California and regulated by the Building Standards Commission. See Section 103 for additional scoping provisions.
2. Energy efficiency standards regulated by the California Energy Commission.
3. All residential buildings constructed throughout the State of California, including but not limited to, hotels, motels, lodging houses, apartments, dwellings, dormitories, condominiums, shelters for homeless persons, congregate residences, employee housing, factory-built housing and other types of dwellings containing sleeping accommodations with or without common toilets or cooking facilities regulated by the Department of Housing and Community Development. See Section 104 for additional scoping provisions.
4. Public elementary and secondary schools, and community college buildings regulated by the Division of the State Architect. See Section 105 for additional scoping provisions.
5. Qualified historical buildings and structures and their associated sites regulated by the State Historical Building Safety Board within the Division of the State Architect.
6. General acute care hospitals, acute psychiatric hospitals, skilled nursing and/or intermediate care facilities, clinics licensed by the Department of Public Health and correctional treatment centers regulated by the Office of Statewide Health Planning and Development. See Section 106 for additional scoping provisions.
7. Graywater systems regulated by the Department of Water Resources and the Department of Housing and Community Development.
8. Green building standards for occupancies where no state agency has authority or expertise, adopted by the California Building Standards Commission. See Section 103 for additional scoping provisions.
101.4 Appendices. Provisions contained in the appendices of this code are not mandatory unless specifically adopted by a city, county, or city and county in compliance with Health and Safety Code Sections 18930 and 18941.5, respectively, for Building Standards Law; Health and Safety Code Section 17950 for State Housing Law; and Health and Safety Code Section 13869.7 for Fire Protection Districts. See Section 101.7 of this code.

101.5 Referenced codes and standards. The codes and standards referenced elsewhere in this code shall be considered part of the requirements of this code to the prescribed extent of each such reference.

101.5.1 Building. The provisions of the California Building Code, California Residential Code and California Existing Building Code, as applicable, shall apply to the construction, alteration, movement, enlargement, replacement, repair, use and occupancy, location, maintenance, removal and demolition of every structure or any appurtenances connected or attached to such buildings or structures.

101.5.2 Electrical. The provisions of the California Electrical Code shall apply to the installation of electrical systems, including but not limited to, alterations, repair, replacement, equipment, appliances, fixtures, fittings and appurtenances thereto.

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ADMINISTRATION

101.5.3 Mechanical. The provisions of the California Mechanical Code shall apply to the installation, alterations, repair and replacement of mechanical systems, including equipment, appliances, fixtures, fittings and/or appurtenances, including ventilating, heating, cooling, air-conditioning and refrigeration systems, incinerators and other energy-related systems.
CMC § 102.4 Medium relevance — show source text
ADMINISTRATION

DIVISION II SCOPE AND ADMINISTRATION

User notes:

About this chapter: Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. Chapter 1 is in two parts: Part 1—Scope and Application (Sections 101–102) and Part 2—Administration and Enforcement (Sections 103–116). Section 101 identifies which buildings and structures come under its purview and references other ICodes as applicable. Standards and codes are scoped to the extent referenced (see Section 102.4).

This code is intended to be adopted as a legally enforceable document and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner. Chapter 1 is largely concerned with maintaining “due process of law” in enforcing the building performance criteria contained in the body of the code.

ICC code development note: Code change proposals to this chapter will be considered by the Administrative Code Development Committee during the 2025 (Group B) Code Development Cycle.

Section 104 was revised for the 2024 edition. For complete information, see the Relocations table in the Preface of this code.

Note: Sections adopted or amended by state agencies are specifically indicated by an agency banner.

PART 1—SCOPE AND APPLICATION

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

[A] 101.1 Title. These regulations shall be known as the Building Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”

[A] 101.2 Scope. The provisions of this code shall apply to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures.

Exception: Detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with this code or the California Residential Code .

[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.

[A] 101.3 Purpose. The purpose of this code is to establish the minimum requirements to provide a reasonable level of safety, health and general welfare through structural strength, means of egress, stability, sanitation, light and ventilation, energy conservation, and for providing a reasonable level of life safety and property protection from the hazards of fire, explosion or dangerous conditions, and to provide a reasonable level of safety to firefighters and emergency responders during emergency operations.

[A] 101.4 Referenced codes. The other codes specified in Sections 101.4.1 through 101.4.7 and referenced elsewhere in this code shall be considered to be part of the requirements of this code to the prescribed extent of each such reference.
CMC § 5303.16.1 Medium relevance — show source text
1, 5303.16.1, 5303.16.2, 5306.1, 5306.2, 5306.2.1, 5306.2.2, 5307.4.6, 5503.1.2, 5503.5.2, 5504.2.1.2, 5504.2.2.2, 5505.4.1, 5604.2, Table 5604.5.2(3), 5605.5, 5701.3, 5704.2.7.7, 5704.2.8.1, 5704.2.8.2, 5704.2.9.3, 5704.2.9.4, 5704.3.3.5, 5704.3.7.1, 5704.3.8, 5705.3.4, 5705.3.5.3, 5705.3.7.1, 5705.3.7.2, 5705.3.7.3, 5705.3.7.4, 5705.3.7.5.1, 5706.2.3, 5706.4.1, 5803.1.1, 5806.4.3, 5808.1, 5808.3, 5808.3.2, 5906.2.2, 5906.2.3, 5906.4.2, 6003.1.4.2, 6005.3.1, 6109.11.2, 6204.1.2, 6306.4, 6404.1.4, 6604.1

CEBC—25: California Existing Building Code

102.3, 1011.5.2, 1103.1, 1104.18, 1105.5.2

CMC—25: California Mechanical Code

201.3, 308.3, 605.1, 605.2.1.1, 605.2.1.2, 605.2.1.3, 605.2.1.4, 605.2.1.5, 605.3, 605.4, 605.4.2.3, 605.4.2.5, 605.5.2, 605.7, 606.1, 606.2, 608.1, 608.3, 608.4, 608.5, 608.8, 608.9.1, 608.10, 608.17, 610.1.1, 903.2.11.4, 904.14, 907.3.1, 909.1, 909.10.2, 909.13.1, 910.4.7, 915.6.1, 1006.2.2.3, 1011.16, 1020.6.1, 1207.4.7, 1207.6.1, 1207.6.1.2.2, 1207.11.8, 2104.2.1, 2105.3, 2301.1, 2301.6, 2309.3.1.2, 2311.3.1, 2311.4.3, 2311.8.2, 2311.
California Mechanical Code Medium relevance — show source text

2
5
10
15
20|190
182
224
277
325
374|1053
708
692
666
640
616|573
468
457
437
419
400|238
227
279
339
393
448|1379
914
896
866
838
810|750
611
596
570
549
526|326
309
381
457
526
592|1751
1146
1126
1092
1060
1028|927
754
734
702
677
651|473
443
547
646
730
808|2631
1689
1665
1626
1587
1550|1346
1098
1074
1037
1005
973| |30|0
2
5
10
15
20
30|184
175
215
265
312
360
461|1168
823
806
777
750
723
670|647
533
521
501
481
461
426|229
219
269
327
379
433
541|1542
1069
1049
1017
985
955
895|852
698
684
662
638
615
574|312
296
366
440
507
570
704|1971
1346
1324
1287
1251
1216
1147|1056
863
846
821
794
768
720|454
424
524
620
702
780
937|2996
1999
1971
1927
1884
1841
1759|1545
1308
1283
1243
1205
1166
1101| |50|0
2
5
CMC § 1.11.8 Medium relevance — show source text
1.11.8 Service utilities. See Section 111.

1.11.9 Stop work order. See Section 114.

1.11.10 Unsafe buildings, structures and equipment. See Section 115.

1.11.11 Adopting agency identification. The provisions of this code applicable to buildings identified in this Section 1.11 will be identified in the Matrix Adoption Tables under the acronym SFM.

SECTION 1.12—STATE LIBRARIAN

RESERVED

SECTION 1.13—DEPARTMENT OF WATER RESOURCES

RESERVED

SECTION 1.14—CALIFORNIA STATE LANDS COMMISSION

RESERVED

1-20 2025 CALIFORNIA EXISTING BUILDING CODE

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DIVISION II SCOPE AND ADMINISTRATION

Note: Sections adopted or amended by state agencies are specifically indicated by an agency banner.

Division II is not adopted by the Department of Housing and Community Development except where specifically indicated.

User notes:

About this chapter: Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. Chapter 1 is in two parts: Part 1—Scope and Administration (Sections 101–102) and Part 2—Administration and Enforcement (Sections 103–117). Section 101 identifies which buildings and structures come under its purview and references other I-Codes as applicable.

This code is intended to be adopted as a legally enforceable document, and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the registered design professional, contractor and property owner.

Section 104 was revised for the 2024 edition of the IEBC. For complete information, see the Relocations table in the Preface of this code.

PART 1—SCOPE AND APPLICATION

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

[A] 101.1 Title. These regulations shall be known as the Existing Building Code of [ NAME OF JURISDICTION ], herein-after referred to as “this code.”

[A] 101.2 Scope. The provisions of this code shall apply to the repair, alteration, change of occupancy, addition to and relocation of existing buildings.

Exception: Detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with this code or the California Residential Code.

[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted or referenced.

101.2.2 Application of fire code. Where work regulated by this code is also regulated by the construction requirements for existing buildings in Chapter 11 of the California Fire Code, such work shall comply with applicable requirements in both codes.
CMC § 101.7. Medium relevance — show source text
Green building measures listed in this table may be mandatory if adopted by a city, county, or city and county as specified in Section 101.7.
2. Required prerequisite for this Tier.
3. These measures are currently required elsewhere in statute or in regulation.|1. Green building measures listed in this table may be mandatory if adopted by a city, county, or city and county as specified in Section 101.7.
2. Required prerequisite for this Tier.
3. These measures are currently required elsewhere in statute or in regulation.|

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DIVISION A4.7 – RESIDENTIAL MODEL ORDINANCE

A4.701.1 General. The voluntary measures of this code are designed and promulgated to be adopted by reference and made mandatory by local ordinance pursuant to Section 101.7. Jurisdictions wishing to adopt the voluntary provisions of this code as an enforceable regulation governing structures and premises should ensure that certain factual information is included in the adopting ordinance and that the measures are appropriate and achievable and are considered to be suitable as mandatory by the city, county, or city and county. The following sample adoption ordinance addresses several key elements of a code adoption ordinance, including the information required for insertion into the code text.

This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code.

SAMPLE RESOLUTION FOR ADOPTION OF THE TIER 1 OR TIER 2 PROVISIONS OF THE CALIFORNIA GREEN BUILDING STANDARDS CODE WITH OR WITHOUT ADDITIONAL ITEMS NECESSARY TO ADDRESS INNOVATIVE CONCEPTS OR LOCAL ENVIRONMENTAL CONDITIONS.

ATTACHMENT___.

SAMPLE RESOLUTION ADOPTING THE CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDICES AS A MANDATORY REFERENCE STANDARD

CITY OF ________________________

RESOLUTION # __________________

RESOLUTION ADOPTING ENHANCED GREEN BUILDING MEASURES FOR NEW AND EXISTING RESIDENTIAL CONSTRUCTION.

WHEREAS, the City/County of ______’s (City or County) General Plan sets forth goals for preserving and improving the natural and built environment of the City/County, protecting the health of its residents and visitors, and fostering its economy; and

WHEREAS, green building is a holistic approach to design, construction and demolition that minimizes the building’s impact on the environment, the occupants and the community; and

WHEREAS, green buildings benefit building industry professionals, residents and communities by improving construction quality; increasing building durability; reducing utility, maintenance, water and energy costs; creating healthier homes; and enhancing comfort and livability; and

WHEREAS, the California Green Building Standards Code appendices have included voluntary tiers to provide a city, county, or city and county, building professionals, and the general public with a range of voluntary green building measures for builders to choose from when constructing homes in California; and

CGBSC § 2025 Medium relevance — show source text

WHEREAS, adoption of the California Green Building Standards Code appendices promotes statewide consistency and predictability for building professionals; and

NOW THEREFORE, BE IT RESOLVED, that the City/County hereby finds that green building design, construction and operation furthers the goals set forth in the City/County General Plan, including land use, conservation, open space and (include others, if applicable).

NOW THEREFORE, BE IT RESOLVED, that newly constructed residential buildings, alterations or additions to residential buildings shall meet the _______ (Tier 1 or Tier 2) measures contained in the California Green Building Standards Code appendices and the green building design, construction and operation innovative concepts or additions or amendment thereto contained in Attachment _____ to address local environmental conditions; and

NOW THEREFORE, BE IT FURTHER RESOLVED, that the City Council or County Board of Supervisors of the City/County of ___________ adopts the California Green Building Standards Code appendices, as they may be amended from time to time, as a City/County mandatory reference document and directs City/County staff to enforce these green building measures as mandatory standards within the City/County.

ADOPTED BY THE FOLLOWING VOTE:

AYES:

NOES:

ABSENT:

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CALIFORNIA GREEN BUILDING STANDARDS CODE – MATRIX ADOPTION TABLE

APPENDIX A5 – NONRESIDENTIAL VOLUNTARY MEASURES

DIVISION A5.1 – PLANNING AND DESIGN

(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	OSHPD	Col11	Col12	Col13	Col14	Col15	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting agency	BSC	BSC- CG	SFM	1	2	1/AC	AC	SS	1	1R	2	3	4	5	5	5	5	5	5	5	5	5
Adopt entire CA chapter		X
Adopt entire chapter as amended (amended sections listed below)
Adopt only those sections that are listed below
Chapter/Section

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-1

CMC § 10005-4026. Medium relevance — show source text
IES Illuminating Engineering Society, 120 Wall St. Fl 17, New York, NY 10005-4026.

IEST Institute of Environmental Sciences and Technology, 1827 Walden Office Square, Suite 400, Schaumburg, IL 60173.

IGSHPA International Ground Source Heat Pump Association, 1723 W. Tyler Ave. Stillwater, OK 74078.

IIAR International Institute of Ammonia Refrigeration, 1001 N. Fairfax Street, Suite 503, Alexandria, VA 22314.

ISO International Organization for Standardization, 1 ch. de la Voie-Creuse, Casa Postale 56, CH-1211 Geneva 20, Switzerland.

MSS Manufacturers Standardization Society of the Valve and Fittings Industry, 127 Park Street NE, Vienna, VA 22180.

NAIMA North American Insulation Manufacturers Association, Inc., 11 Canal Center Plaza #103, Alexandria, VA 22314.

NEBB National Environmental Balancing Bureau, 8575 Grovemont Circle, Gaithersburg, MD 20877.

NFPA National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471.

NGWA National Ground Water Association, 601 Dempsey Road, Westerville, Ohio 43081-8978.

NSF NSF International, 789 N. Dixboro Road, Ann Arbor, MI 48105.

SAE Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, PA 15096.

SMACNA Sheet Metal and Air Conditioning Contractors National Association, 4201 Lafayette Center Drive, Chantilly, VA 20151-1219.

UL Underwriters Laboratories, Inc., 333 Pfingsten Road, Northbrook, IL 60062.

384 2025 CALIFORNIA MECHANICAL CODE

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APPENDICES

The appendices are intended to supplement the provisions of the installation requirements of this code. The definitions in Chapter 2 are also applicable to the appendices.

TABLE OF CONTENTS

»

»

Appendix A Page

Residential Plans Examiner Review Form for HVAC System Design..............................................................387

Appendix B

Procedures to be Followed to Place Gas Equipment in Operation..................................................................391

Appendix C

Installation and Testing of Oil (Liquid) Fuel-Fired Equipment ..........................................................................395

Appendix D

Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks ..........................................403

Appendix E

Sustainable Practices ......................................................................................................................................411

Appendix F

Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design ..................................533

Appendix G

Example Calculation of Outdoor Air Rate........................................................................................................545

Appendix H

Professional Qualifications ..............................................................................................................................549

Appendix I

Indoor Horticultural Facilities ..........................................................................................................................553

Appendix J

Clean Air Delivery............................................................................................................................................559

2025 CALIFORNIA MECHANICAL CODE 385

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386 2025 CALIFORNIA MECHANICAL CODE

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CMC § 160.3 Medium relevance — show source text
Mass radiant floor slab systems shall incorporate floor temperature onto the optimum start algorithm. Exception to Section 160.3(a)2J: Systems that must operate continuously.

(b) Dwelling unit space-conditioning and air distribution systems.
1. Building cooling and heating loads. Building heating and cooling loads shall be determined using a method based on any one of the following, using cooling and heating loads as two of the criteria for equipment sizing and selection: A. The ASHRAE Handbook, Equipment Volume, Applications Volume and Fundamentals Volume; or B. The SMACNA Residential Comfort System Installation Standards Manual; or
C. The ACCA Manual J.

Exception to Section 160.3(b)1: Block loads, the total load for all rooms combined that are served by the central equipment, may be used for the purpose of system sizing for additions. NOTE: Heating systems are required to have a minimum heating capacity adequate to meet the minimum requirements of the CBC.
1. Design conditions . Design conditions shall be determined in accordance with the following: A. For the purpose of sizing the space-conditioning (HVAC) system, the indoor design temperatures shall be 68°F for heating and 75°F for cooling. B. Outdoor design conditions shall be selected from one of the following: i. Reference Joint Appendix JA2, which is based on data from the ASHRAE Climatic Data for Region X; or ii. The ASHRAE Handbook Fundamentals Volume; or
iii. The ACCA Manual J.

C. The outdoor design temperatures for heating shall be no lower than the 99.0 percent Heating Dry Bulb or the Heating Winter Median of Extremes values.

D. The outdoor design temperatures for cooling shall be no greater than the 1.0 percent Cooling Dry Bulb and Mean Coincident Wet Bulb values.

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MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS
1. Outdoor condensing units . A. Clearances. Installed air conditioner and heat pump outdoor condensing units shall have a clearance of at least 5 feet (1.5 meters) from the outlet of any dryer vent. B. Liquid line drier. Installed air conditioner and heat pump systems shall be equipped with liquid line filter driers if required, as specified by manufacturer’s instructions.
2. Central forced-air heating furnaces . A. Temperature rise . Central forced-air heating furnace installations shall be configured to operate in conformance with the furnace manufacturer's maximum inlet-to-outlet temperature rise specifications.
3. Air-distribution and ventilation system ducts, plenums and fans. A. CMC compliance.
i. All air-distribution system ducts and plenums, including, but not limited to, mechanical closets and air-handler boxes, shall meet the requirements of the CMC Sections 601.0, 602.0, 603.0, 604.0 and 605.0 and ANSI/SMACNA006-2006 HVAC Duct Construction Standards Metal and Flexible 3rd Edition, incorporated herein by reference. ii. Portions of supply-air and return-air ducts and plenums of a space heating or cooling system shall be insulated in accordance with either Subsection a or b below:

a. Ducts shall have a minimum installed level of R-6.0, or
CMC § 2.25 Medium relevance — show source text
00|2.25|0.70|DR|3.70|1.05|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|33 mil cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|16|3.85|1.45|DR|DR|3.40|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|33 mil cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|24|3.40|DR|DR|DR|2.70|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#8 Screw|Steel thick-
ness plus 3
threads|12|3.00|1.80|DR|DR|3.00|0.65|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#8 Screw|Steel thick-
ness plus 3
threads|16|3.00|1.00|DR|DR|2.85|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#8 Screw|Steel thick-
ness plus 3
threads|24|2.85|DR|DR|DR|2.20|DR|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|12|4.00|3.85|2.80|1.80|4.00|3.05|1.50|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|16|4.00|3.30|1.95|0.60|4.00|2.25|DR|DR| |Minimum 33
mil steel
furring or
minimum
1x wood
furringc|43 mil or
thicker cold-
formed steel
stud|#10 screw|Steel thick-
ness plus 3
threads|24|4.00|2.25|DR|DR|4.00|0.65|DR|DR| |For SI: 1 inch = 25.4 mm, 1 pound per square foot (psf) = 0.0479 kPa, 1 pound per square inch = 0.00689 MPa.
DR = Design Required, o.c. = on center.
a. Wood furring shall be spruce-pine-fir or any softwood species with a specific gravity of 0.42 or greater.

CEC § 384 Medium relevance — show source text

384 2025 CALIFORNIA MECHANICAL CODE

APPENDICES

The appendices are intended to supplement the provisions of the installation requirements of this code. The definitions in Chapter 2 are also applicable to the appendices.

TABLE OF CONTENTS

Appendix A Page

Residential Plans Examiner Review Form for HVAC System Design..............................................................387

Appendix B

Procedures to be Followed to Place Gas Equipment in Operation..................................................................391

Appendix C

Installation and Testing of Oil (Liquid) Fuel-Fired Equipment ..........................................................................395

Appendix D

Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks ..........................................403

Appendix E

Sustainable Practices ......................................................................................................................................411

Appendix F

Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design ..................................533

Appendix G

Example Calculation of Outdoor Air Rate........................................................................................................545

Appendix H

Professional Qualifications ..............................................................................................................................549

Appendix I

Indoor Horticultural Facilities ..........................................................................................................................553

Appendix J

Clean Air Delivery............................................................................................................................................559

2025 CALIFORNIA MECHANICAL CODE 385

386 2025 CALIFORNIA MECHANICAL CODE

CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE

APPENDIX A – RESIDENTIAL PLAN EXAMINER REVIEW FORM FOR HVAC SYSTEM DESIGN

(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	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
Adopt Entire Chapter as amended (amended sections listed below)
Adopt only those sections that are listed below
Chapter/Section

CMC § 101.1 Medium relevance — show source text
This code is intended to be adopted as a legally enforceable document, and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the registered design professional, contractor and property owner.

Section 104 was revised for the 2024 edition of the IEBC. For complete information, see the Relocations table in the Preface of this code.

PART 1—SCOPE AND APPLICATION

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

[A] 101.1 Title. These regulations shall be known as the Existing Building Code of [ NAME OF JURISDICTION ], herein-after referred to as “this code.”

[A] 101.2 Scope. The provisions of this code shall apply to the repair, alteration, change of occupancy, addition to and relocation of existing buildings.

Exception: Detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with this code or the California Residential Code.

[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted or referenced.

101.2.2 Application of fire code. Where work regulated by this code is also regulated by the construction requirements for existing buildings in Chapter 11 of the California Fire Code, such work shall comply with applicable requirements in both codes.

[A] 101.3 Purpose. The intent of this code is to provide flexibility to permit the use of alternative approaches to achieve compliance with minimum requirements to provide a reasonable level of safety, health, property protection and general welfare insofar as they are affected by the repair, alteration, change of occupancy, addition and relocation of existing buildings.

[A] 101.4 Applicability. This code shall apply to the repair, alteration, change of occupancy, addition and relocation of existing buildings, regardless of occupancy, subject to the criteria of Sections 101.4.1 and 101.4.2.

[A] 101.4.1 Buildings not previously occupied. A building or portion of a building that has not been previously occupied or used for its intended purpose, in accordance with the laws in existence at the time of its completion, shall be permitted to comply with the provisions of the laws in existence at the time of its original permit unless such permit has expired. Subsequent permits shall comply with the California Building Code or California Residential Code, as applicable, for new construction.

[A] 101.4.2 Buildings previously occupied. The legal occupancy of any building existing on the date of adoption of this code shall be permitted to continue without change, except as is specifically covered in this code, the California Fire Code, or the Inter- national Property Maintenance Code, or as is deemed necessary by the code official for the general safety and welfare of the occupants and the public.

[A] 101.5 Safeguards during construction. Construction work covered in this code, including any related demolition, shall comply with the requirements of Chapter 15.
CMC § 101.1 Medium relevance — show source text
PART 1—SCOPE AND APPLICATION

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

[A] 101.1 Title. These regulations shall be known as the Building Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”

[A] 101.2 Scope. The provisions of this code shall apply to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures.

Exception: Detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with this code or the California Residential Code .

[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.

[A] 101.3 Purpose. The purpose of this code is to establish the minimum requirements to provide a reasonable level of safety, health and general welfare through structural strength, means of egress, stability, sanitation, light and ventilation, energy conservation, and for providing a reasonable level of life safety and property protection from the hazards of fire, explosion or dangerous conditions, and to provide a reasonable level of safety to firefighters and emergency responders during emergency operations.

[A] 101.4 Referenced codes. The other codes specified in Sections 101.4.1 through 101.4.7 and referenced elsewhere in this code shall be considered to be part of the requirements of this code to the prescribed extent of each such reference.

[A] 101.4.1 Gas. The provisions of the California Plumbing Code and/or the California Mechanical Code shall apply to the installation of gas piping from the point of delivery, gas appliances and related accessories as covered in this code. These requirements apply to gas piping systems extending from the point of delivery to the inlet connections of appliances and the installation and operation of residential and commercial gas appliances and related accessories.

[A] 101.4.2 Mechanical. The provisions of the California Mechanical Code shall apply to the installation, alterations, repairs and replacement of mechanical systems, including equipment, appliances, fixtures, fittings and appurtenances, including ventilating, heating, cooling, air-conditioning and refrigeration systems, incinerators and other energy-related systems.

[A] 101.4.3 Plumbing. The provisions of the California Plumbing Code shall apply to the installation, alteration, repair and replacement of plumbing systems, including equipment, appliances, fixtures, fittings and appurtenances, and where connected to a water or sewage system and all aspects of a medical gas system. The provisions of the California Plumbing Code shall apply to private sewage disposal systems.

[A] 101.4.4 Property maintenance. The provisions of the California Existing Building Code shall apply to existing structures and premises; equipment and facilities; light, ventilation, space heating, sanitation, life and fire safety hazards; responsibilities of owners, operators and occupants; and occupancy of existing premises and structures.
CMC § 1.5 Medium relevance — show source text
[California Code of Regulations, Title 14, Division 1.5, §1270.08] Distance Measurements.

All specified or referenced distances are measured along the ground unless otherwise stated.

1.12.2 Agency identification. The provisions of this code applicable to wildland-urban interface areas identified in Section 1.12 are identified in the body of the code by square brackets containing references to applicable Title 14 sections and in the Cross Reference Table located in Appendix H, Section H107.

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DIVISION II

SCOPE AND ADMINISTRATION

User notes:

About this chapter: Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. Chapter 1 is in two parts: Part 1–General Provisions (Sections 101–102) and Part 2—Administration and Enforcement (Sections 103–113). Section 101 identifies which buildings and structures come under its purview and references other California Codes as applicable.

This code is intended to be adopted as a legally enforceable document and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.

Note: Sections adopted or amended by state agencies are specifically indicated by an agency banner or indicated in the Matrix Adoption Table.

PART 1—GENERAL PROVISIONS

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

[A] 101.1 Title. These regulations shall be known as the California Wildland-Urban Interface Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”

[A] 101.2 Scope. This code applies to building materials, systems and/or assemblies used in the exterior design and construction of new buildings located within a wildland-urban interface (WUI) area and contains minimum requirements to mitigate conditions that might cause a fire originating in a structure to ignite vegetation in the wildland-urban interface (WUI) area, and conversely, a wildfire burning in vegetative fuels to transmit fire to buildings and threaten to destroy life, overwhelm fire suppression capabilities or result in large property losses.

[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.

[A] 101.3 Purpose. The purpose of this code is to establish minimum regulations for the safeguarding of life and for property protection. Regulations in this code are intended to mitigate the risk to life and structures from intrusion of fire from wildland fire exposures and fire exposures from adjacent structures and to mitigate structure fires from spreading to wildland fuels. The extent of this regulation is intended to be tiered commensurate with the relative level of hazard present.

The unrestricted use of property in wildland-urban interface areas is a potential threat to life and property from fire and resulting erosion. Safeguards to prevent the occurrence of fires and to provide adequate fire protection facilities to control the spread of fire in wildland-urban interface areas shall be in accordance with this code.
CMC § 1.12.0 Medium relevance — show source text
1.8. Organized camps.

1.9. Residential structures.

(2) Tents, awnings, or other fabric enclosures used in connection with any occupancy.

(3) Fire alarm devices, equipment, and systems in connection with any occupancy.

(4) Hazardous materials, flammable, and combustible liquids.

(5) Public school automatic fire detection, alarm, and sprinkler systems.

(6) Wildland-urban interface fire areas.

(15)Section 1.12.0 is reserved for public libraries constructed and renovated using funds from the California Library Construction and Renovation Bond Act of 1988 and regulated by the State Librarian.

(16)Section 1.13.0 is reserved for the Department of Water Resources.

(17)For applications listed in Section 1.9.1 regulated by the Division of the State Architect – Access Compli-

ance, outdoor environments and uses shall be clas- sified according to accessibility uses described in Chapters 11A and 11B.

(18)Section 1.14.0 is reserved for Marine Oil Terminals regulated by the California State Lands Commis- sion.

1.1.4 Appendices. Provisions contained in the appendices of this code shall not apply unless specifically adopted by a state agency or adopted by a local enforcing agency in compliance with Health and Safety Code Section 18901 et. seq. for Building Standards Law, Health and Safety Code Section 17950 for State Housing Law and Health and Safety Code Section 13869.7 for Fire Protection Districts. See Section 1.1.8 of this code.

1.1.5 Referenced Codes. The codes, standards and publica- tions adopted and set forth in this code, including other codes, standards, and publications referred to therein are, by title and date of publication, hereby adopted as standard refer- ence documents of this code. When this code does not specif- ically cover any subject related to building design and construction, recognized architectural, or engineering prac- tices shall be employed. The National Fire Codes, standards, and the Fire Protection Handbook of the National Fire Protection Association are permitted to be used as authori- tative guides in determining recognized fire prevention engi- neering practices.

1.1.6 NonBuilding Standards, Orders and Regulations. Requirements contained in the Uniform Mechanical Code, or in any other referenced standard, code or document, which are not building standards as defined in Health and Safety Code Section 18909, shall not be construed as part of the provisions of this code. For nonbuilding standards, orders, and regulations, see other titles of the California Code of Regulations.

1.1.7 Order of Precedence and Use.

1.1.7.1 Differences. In the event of any differences between these building standards and the standard refer- ence documents, the text of these building standards shall

govern.

1.1.7.2 Specific Provisions. Where a specific provision varies from a general provision, the specific provision shall apply.
CMC § 1-11 Medium relevance — show source text
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DIVISION II SCOPE AND ADMINISTRATION

User notes:

About this chapter: Chapter 1 establishes the limits of applicability of the code and describes how the code is to be applied and enforced. Chapter 1 is in two parts: Part 1—General Provisions (Sections 101–102) and Part 2—Administrative Provisions (Sections 103–115). Section 102 identifies which buildings and structures come under its purview and references other I-Codes as applicable.

This code is intended to be adopted as a legally enforceable document, and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the code official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.

ICC code development note: Code change proposals to this chapter will be considered by the Administrative Code Development Committee during the 2025 (Group B) Code Development Cycle.

Section 104 was revised for the 2024 edition. For clarity, the relocation marginal markings have not been included. For complete information, see the Relocations table in the Preface of this code.

PART 1—GENERAL PROVISIONS

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

Note: Sections adopted or amended by state agencies are specifically indicated by an agency banner or indicated in the Matrix Adoption Table.

[A] 101.1 Title. These regulations shall be known as the Fire Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”

[A] 101.2 Scope. This code establishes regulations affecting or relating to structures, processes, premises and safeguards regarding all of the following:
1. The hazard of fire and explosion arising from the storage, handling or use of structures, materials or devices.
2. Conditions hazardous to life, property or public welfare in the occupancy of structures or premises.
3. Fire hazards in the structure or on the premises from occupancy or operation.
4. Matters related to the construction, extension, repair, alteration or removal of fire protection systems.
5. Conditions affecting the safety of firefighters and emergency responders during emergency operations.
[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.

[A] 101.3 Purpose. The purpose of this code is to establish the minimum requirements for providing a reasonable level of life safety and property protection from the hazards of fire, explosion or dangerous conditions in new and existing buildings, structures and premises, and to provide a reasonable level of safety to firefighters and emergency responders during emergency operations.

[A] 101.4 Severability. If a section, subsection, sentence, clause or phrase of this code is, for any reason, held to be unconstitutional, such decision shall not affect the validity of the remaining portions of this code.
CMC § 1.1.3.2 Medium relevance — show source text
1.1.3.2 State-Regulated Buildings, Structures, and Applications. The model code, state amendments to the model code, and/or state amendments where there are no relevant model code provisions shall apply to the following buildings, structures, and applications regu- lated by state agencies as specified in Sections 1.2.0 through 1.14.0, except where modified by local ordinance pursuant to Section 1.1.8. When adopted by a state agency, the provisions of this code shall be enforced by the appropriate enforcing agency, but only to the extent of authority granted to such agency by the state legislature.

Note: See “How to Distinguish Between Model Code Language and California Amendments” in the front of the code.

(1) State-owned buildings, including buildings constructed by the Trustees of the California State University, and to the extent permitted by California laws, buildings designed and constructed by the

Regents of the University of California, and regu- lated by the Building Standards Commission. See Section 1.2.0 for additional scope provisions.

(2) Section 1.3.0 is reserved for the Board of State and Community Corrections.

(3) Section 1.4.0 is reserved for the Department of Consumer Affairs.

(4) Section 1.5.0 is reserved for the California Energy Commission.

(5) Section 1.6.0 is reserved for the Department of Food and Agriculture.

(6) Organized camps, laboratory animal quarters, public swimming pools, radiation protection, commissaries serving mobile food preparation vehi- cles, and wild animal quarantine facilities regulated by the Department of Public Health. See Section 1.7.0 for additional scope provisions.

(7) Hotels, motels, lodging houses, apartments, dwellings, dormitories, condominiums, shelters for homeless persons, congregate residences, employee housing, factory-built housing and other types of dwellings containing sleeping accommodations with or without common toilets or cooking facilities. See Section 1.8.2.1.1 for additional scope provisions.

(8) Accommodations for persons with disabilities in buildings containing newly constructed covered multifamily dwellings, new common use areas serving existing covered multifamily dwellings, additions to existing buildings where the addition alone meets the definition of covered multifamily dwellings and new common-use areas serving new covered multifamily dwellings which are regulated by the Department of Housing and Community Development. See Section 1.8.2.1.2 for additional scope provisions.

(9) Permanent buildings and permanent accessory build- ings or structures constructed within mobilehome parks and special occupancy parks regulated by the Department of Housing and Community Development. See Section 1.8.2.1.3 for additional scope provisions.

(10)Accommodations for persons with disabilities regu- lated by the Division of the State Architect. See Section 1.9.1 for additional scope provisions.

(11) Public elementary and secondary schools, commu- nity college buildings and state-owned or state- leased essential service buildings regulated by the Division of the State Architect. See Section 1.9.2 for additional scope provisions.

(12)Reserved for the State Historical Building Safety Board with the Division of the State Architect.
CMC § 1-16 Medium relevance — show source text
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DIVISION II SCOPE AND ADMINISTRATION

User notes:

About this chapter: Chapter 1 Division II establishes the limits of applicability of this code and describes how the code is to be applied and enforced. Chapter 1 Division II is in two parts: Part 1—Scope and Application (Sections R101–R102) and Part 2—Administration and Enforcement (Sections R103–R114). Section R101 identifies which buildings and structures come under its purview and references other I-Codes as applicable. Standards and codes are scoped to the extent referenced (see Section R102.4).

The one- and two-family dwelling code is intended to be adopted as a legally enforceable document, and it cannot be effective without adequate provisions for its administration and enforcement. The provisions of Chapter 1 establish the authority and duties of the building official appointed by the authority having jurisdiction and also establish the rights and privileges of the design professional, contractor and property owner.

Division II is not adopted by the Department of Housing and Community Development except where specifically indicated. Note: Specific sections of Chapter 1, Division II adopted by the State Fire Marshal will be indicated in the Matrix Adoption Table.

PART 1—SCOPE AND APPLICATION

SECTION R101—SCOPE AND GENERAL REQUIREMENTS

R101.1 Title. These provisions shall be known as the Residential Code for One- and Two-family Dwellings of [ NAME OF JURISDICTION ], and shall be cited as such and will be referred to herein as “this code.”

R101.2 Scope. The provisions of this code shall apply to the construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above grade plane in height.

Exception: The following shall be permitted to be constructed in accordance with this code where provided with an automatic sprinkler system complying with Section R309 :
1. Live/work units located in townhouses and complying with the requirements of Section 508.5 of the California Building Code.
2. Owner-occupied lodging houses with five or fewer guestrooms.
3. A care facility with five or fewer persons receiving custodial care within a dwelling unit.
4. A care facility with five or fewer persons receiving medical care within a dwelling unit.
5. A day care facility for five or fewer persons of any age receiving care within a dwelling unit.
R101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.

R101.3 Purpose. The purpose of this code is to establish minimum requirements to provide a reasonable level of safety, health and general welfare through affordability, structural strength, means of egress, stability, sanitation, light and ventilation, energy conservation and safety to life and property from fire and other hazards and to provide a reasonable level of safety to firefighters and emergency responders during emergency operations.

SECTION R102—APPLICABILITY

R102.1 General. Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall be applicable. Where, in any specific case, different sections of this code specify different materials, methods of construction or other requirements, the most restrictive shall govern.
CMC § 5-0 Medium relevance — show source text
(or less)
5-0
6-0
7-4|#4 at 72
#4 at 72
#4 at 72
#4 at 72|#4 at 72
#4 at 72
#4 at 72
#5 at 72|#4 at 72
#4 at 72
#5 at 72
#6 at 72| |8-0|4 (or less)
5-0
6-0
7-0
8-0|#4 at 72
#4 at 72
#4 at 72
#4 at 72
#5 at 72|#4 at 72
#4 at 72
#4 at 72
#5 at 72
#6 at 72|#4 at 72
#4 at 72
#5 at 72
#6 at 72
#8 at 72| |8-8|4 (or less)
5-0
6-0
7-0
8-8e|#4 at 72
#4 at 72
#4 at 72
#4 at 72
#5 at 72|#4 at 72
#4 at 72
#4 at 72
#5 at 72
#7 at 72|#4 at 72
#4 at 72
#5 at 72
#6 at 72
#8 at 72| |9-4|4 (or less)
5-0
6-0
7-0
8-0
9-4e|#4 at 72
#4 at 72
#4 at 72
#4 at 72
#5 at 72
#6 at 72|#4 at 72
#4 at 72
#5 at 72
#5 at 72
#6 at 72
#7 at 72|#4 at 72
#4 at 72
#5 at 72
#6 at 72
#7 at 72
#8 at 72| |10-0|4 (or less)
5-0
6-0
7-0
8-0
9-0e
10-0e|#4 at 72
#4 at 72
#4 at 72
#4 at 72
#5 at 72
#6 at 72
#7 at 72|#4 at 72
#4 at 72
#5 at 72
#6 at 72
#6 at 72
#7 at 72
#8 at 72|#4 at 72
#4 at 72
#5 at 72
#6 at 72
#7 at 72
#8 at 72
#9 at 72| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/m.
a. For design lateral soil loads, see Section 1610.
b. Provisions for this table are based on design and construction requirements specified in Section 1807.1.6.3.
c. For alternative reinforcement, see Section 1807.1.6.3.1.
d. For height of unbalanced backfill, see Section 1807.1.2.
e.
CMC § 101.1 Medium relevance — show source text
PART 1—GENERAL PROVISIONS

SECTION 101—SCOPE AND GENERAL REQUIREMENTS

Note: Sections adopted or amended by state agencies are specifically indicated by an agency banner or indicated in the Matrix Adoption Table.

[A] 101.1 Title. These regulations shall be known as the Fire Code of [ NAME OF JURISDICTION ], hereinafter referred to as “this code.”

[A] 101.2 Scope. This code establishes regulations affecting or relating to structures, processes, premises and safeguards regarding all of the following:
1. The hazard of fire and explosion arising from the storage, handling or use of structures, materials or devices.
2. Conditions hazardous to life, property or public welfare in the occupancy of structures or premises.
3. Fire hazards in the structure or on the premises from occupancy or operation.
4. Matters related to the construction, extension, repair, alteration or removal of fire protection systems.
5. Conditions affecting the safety of firefighters and emergency responders during emergency operations.
[A] 101.2.1 Appendices. Provisions in the appendices shall not apply unless specifically adopted.

[A] 101.3 Purpose. The purpose of this code is to establish the minimum requirements for providing a reasonable level of life safety and property protection from the hazards of fire, explosion or dangerous conditions in new and existing buildings, structures and premises, and to provide a reasonable level of safety to firefighters and emergency responders during emergency operations.

[A] 101.4 Severability. If a section, subsection, sentence, clause or phrase of this code is, for any reason, held to be unconstitutional, such decision shall not affect the validity of the remaining portions of this code.

[A] 101.5 Validity. In the event any part or provision of this code is held to be illegal or void, this shall not have the effect of making void or illegal any of the other parts or provisions hereof, which are determined to be legal; and it shall be presumed that this code would have been adopted without such illegal or invalid parts or provisions.

SECTION 102—APPLICABILITY

[A] 102.1 Construction and design provisions. The construction and design provisions of this code shall apply to:
1. Structures, facilities and conditions arising after the adoption of this code.
2. Existing structures, facilities and conditions not legally in existence at the time of adoption of this code.
3. Existing structures, facilities and conditions where required in Chapter 11.
4. Existing structures, facilities and conditions that, in the opinion of the fire code official, constitute a distinct hazard to life or property.
[A] 102.2 Administrative, operational and maintenance provisions. The administrative, operational and maintenance provisions of this code shall apply to:
1. Conditions and operations arising after the adoption of this code.
2. Existing conditions and operations.
[A] 102.3 Change of use or occupancy. A change of occupancy shall not be made unless the use or occupancy is made to comply with the requirements of this code and the California Existing Building Code .

Exception: Where approved by the fire code official, a change of occupancy shall be permitted without complying with the requirements of this code and the California Existing Building Code, provided that the new or proposed use or occupancy is less hazardous, based on life and fire risk, than the existing use or occupancy.

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Frequently asked questions

May a city adopt only part of an appendix or amend an appendix?

Yes. A city or county may adopt appendices (or portions) and may adopt with amendments by local ordinance — the adopting ordinance or code amendment will show the exact text and applicability. See the CMC adoption/matrix guidance and the sample local adoption language in the Green Building Standards Code appendices.

If an appendix is not adopted locally, can I still use it as guidance?

Yes. Appendices are intended to supplement the code and often provide helpful procedures, examples, and best practices; they can be used voluntarily as guidance even when not mandatory. The CMC explicitly treats appendices as supplemental unless adopted. § 1.1.4

Where do I confirm whether my jurisdiction has adopted a CMC appendix?

Check the local jurisdiction’s municipal code (ordinances), contact the local building department, or review the code’s matrix/adoption tables that show state agency adoptions. The CMC front matter and matrix notes explain and list adoption status.

Does a state agency adoption override a local decision?

A state‑agency adoption applies to the scopes that agency regulates; local jurisdictions enforce what they have authority over. The CMC explains state agency adoption authority and references the Health & Safety Code requirements that govern adoption scope. § 1.1.4 and related matrix notes.

If my permit was filed before an appendix adoption ordinance took effect, which rules apply?

Typically the rules in effect at the time of permit application govern. If an appendix is adopted after permit application, the local adoption ordinance or the authority having jurisdiction will specify effective dates and transition rules — check the adopting ordinance and the local building department.

Ask about the CMC

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California Mechanical Code