CRC · California Residential Code

Where to find the official list of referenced standards (Chapter 44)

Q: Where exactly in the CRC do I look for the official standard edition and the CRC sections that depend on it?

Look in Chapter 44 — Referenced Standards ; each entry shows the standard ID, edition/date, title, and the CRC section(s) that reference it. See § 44 .

Q: If Chapter 44 lists a standard but a CRC section seems silent, which controls?

The CRC section that references the standard and § R102.4 control; the standard applies only to the degree the CRC section incorporates it. See § R102.4 .

Chapter 44 is the CRC’s master list of outside standards — it shows the exact standard edition and which CRC sections rely on it; use Chapter 44 plus § R102.4 to know which standard edition applies and how it’s enforceable.

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Last reviewed: July 6, 2026

What the code requires — plain English

Chapter 44 of the California Residential Code (CRC) is the official place the Code lists every outside referenced standard used by the CRC — by publisher, standard ID, edition/date, title, and the CRC sections that reference it. The chapter makes those standards part of the enforceable code “to the extent of the reference,” and instructs that the application of referenced standards is governed by § R102.4.

The single most important rule: use Chapter 44 to find the exact standard edition and the CRC sections that rely on it; then apply that standard only to the degree the CRC actually references it (see § R102.4).

Requirements in detail

What Chapter 44 contains

A comprehensive, alphabetized list of referenced standards showing: the promulgating agency, standard identification and edition, title, and the CRC section(s) that reference it.
A note that the listed standards apply only to the CRC sections that are adopted in California (i.e., a standard is enforceable only where the CRC references it).
Cross-references to the CRC sections that require a given standard (for example, you will find entries such as ANSI/ACCA Manual J—2016 listed with Table R301.2).

How to use Chapter 44 (decision matrix)

Decision / question	What to look for in Chapter 44	Code Reference
Which standard applies to a CRC requirement?	Find the standard by publisher or acronym (alphabetical lists) and read the CRC sections column to see where it is referenced.	§ 44
Which edition/version do I use?	Chapter 44 prints the edition/effective date for each listed standard; that is the edition the CRC references.	§ 44
How broadly does the standard apply?	Apply the standard only “to the extent of the reference” in the CRC; see how the CRC section cites or incorporates the standard (full adoption vs. limited clause).	§ R102.4
Where is the standard cited in the CRC?	The right-hand column (or following text) in Chapter 44 lists the exact CRC section(s) (e.g., Table R301.2, R303.8, R309.1.1).	§ 44
Are California agency amendments or agency-only standards included?	Chapter 44 notes state-agency standards and directs you to those agency code parts (see matrix/adoption notes in Chapter 44).	§ 44

Organization and practical pointers

Standards are grouped by promulgating agency (ASTM, ANSI, NFPA, ICC, etc.) and listed alphabetically.
Each line typically shows the standard ID (with edition/date), the title, and the CRC section(s) that reference it — use that to link the external standard to the CRC requirement you’re enforcing or designing to.

Exceptions & special cases

Chapter 44 explicitly states that referenced standards are applicable only to those CRC sections that are adopted in California; a standard in Chapter 44 is not a free-standing, statewide adoption beyond the code’s references.
Some standards shown in Chapter 44 may be further amended by California or state agencies (for example, certain NFPA or SFM entries); the Chapter will indicate agency-specific notes and point to the applicable Title‑24 part when applicable.
If a CRC section incorporates only part of a standard (for example, a test method or a specific table), you must follow CRC wording and apply only the referenced portion — see § R102.4 for how incorporated standards become enforceable.

Common mistakes

Treating a listed standard as fully adopted everywhere: the standard only applies where the CRC specifically references it (Chapter 44 + § R102.4).
Using the wrong edition: Chapter 44 lists the edition/date — using a newer or older edition without CRC language allowing it can create noncompliance.
Assuming the Chapter lists agency-only standards in the same way — state agency standards may appear differently and may be located in other Title‑24 parts or in agency regulations (Chapter 44 will note those).

Worked example — concrete scenario

Scenario: A plan reviewer sees a heating-load calculation note that points to Table R301.2 for required load determination.

Step 1 — Find the referenced standard in Chapter 44: search Chapter 44 for ACCA / ANSI/ACCA 2 Manual J—2016. Chapter 44 lists ANSI/ACCA 2 Manual J—2016: Residential Load Calculation and shows it is used by Table R301.2.

Step 2 — Use the exact edition: because Chapter 44 lists the 2016 edition, the reviewer must evaluate the load calculation per Manual J—2016 (the edition printed in Chapter 44) unless CRC text or an amendment explicitly allows a different edition.

Step 3 — Apply only to the referenced requirement: apply Manual J where Table R301.2 requires a load calculation; do not assume Manual J prescribes unrelated HVAC installation details unless the CRC section also references them. See § R102.4 for how the referenced standard is applied.

Related provisions

§ 44 — Chapter 44, Referenced Standards (chapter text and listings).
§ R102.4 — Application of referenced standards; standards become enforceable “to the extent of the reference.”
Table R301.2 — Example location where a referenced standard (e.g., Manual J) is invoked; Chapter 44 cross‑lists that connection.
§ R303.8 — Example CRC section that cites a referenced standard (shown in Chapter 44 entries).
§ R309.1.1 — Example (NFPA 13D) citation shown in Chapter 44 for residential sprinkler standards.

Code references

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

CRC § 44-2 High relevance — show source text
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Part IX— Referenced Standards

44 REFERENCED STANDARDS

Notwithstanding California laws and regulations, these referenced standards shall be applicable only to those California Residential Code sections that are adopted.

User notes:

About this chapter: The one- and two-family dwelling code contains numerous references to standards promulgated by other organizations that are used to provide requirements for materials, products and methods of construction. Chapter 44 contains a comprehensive list of all standards that are referenced in this code. These standards, in essence, are part of this code to the extent of the reference to the standard.

This chapter lists the standards that are referenced in various sections of this document. The standards are listed herein by the promulgating agency of the standard, the standard identification, the effective date and title, and the section or sections of this document that reference the standard. The application of the referenced standards shall be as specified in Section R102.4.

ABTG Applied Building Technology Group LLC6300 Enterprise Lane Madison, WI 53719

ANSI/ABTG FS 100—2012 (R2018): Standard Requirements for Wind Pressure Resistance of Foam Plastic Insulation Sheathing Used in Exterior Wall Covering Assemblies

R303.8

ACCA Air Conditioning Contractors of America 1330 Braddock Place, Suite 350 Alexandria, VA 22314

ANSI/ACCA 2 Manual J—2016: Residential Load Calculation

Table R301.2

ACI American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331

318—19: Building Code Requirements for Structural Concrete R402.2, R404.1.3, R404.1.3.1, Table R404.1.3.2(2), Table R404.1.3.2(5), Table R404.1.3.2(6), Table R404.1.3.2(7), Table R404.1.3.2(8), R404.1.3.3, R404.1.3.4, R404.1.4.2, R404.5.1, R608.1, R608.1.1, R608.1.2, R608.2, R608.5.1, R608.6.1, R608.8.2, R608.9.2, R608.9.3

332—20: Residential Code Requirements for Structural Concrete

R402.2, R403.1, R404.1.3, R404.1.3.4, R404.1.4.2, R506.1

AISI American Iron and Steel Institute 25 Massachusetts Avenue, NW Suite 800 Washington, DC 20001

AISI S100—16 (2020) w/S2—20: North American Specification for the Design of Cold-Formed Steel Structural Members, 2016 Edition (Reaffirmed 2020), with Supplement 2, 2020 Edition

R608.9.2, R608.9.3

AISI S220—20: North American Standard for Cold-Formed Steel Nonstructural Framing, 2020 Edition

R702.3.3

AISI S230—19: North American Standard for Cold-Formed Steel Framing—Prescriptive Method for One and Two Family Dwellings, 2019 Edition
CRC § 102.4 High relevance — show source text
Chapter 34 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 35 Electrical Definitions.

Chapter 35 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 36 Services.

Chapter 36 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 37 Branch Circuit and Feeder Requirements.

Chapter 37 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 38 Wiring Methods.

Chapter 38 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 39 Power and Lighting Distribution.

Chapter 39 is not adopted in California. See California Electrical Code, Title 24, Part 3.

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Chapter 40 Devices and Luminaires.

Chapter 40 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 41 Appliance Installation.

Chapter 41 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 42 Swimming Pools.

Chapter 42 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 43 Class 2 Remote-control, Signaling and Power-limited Circuits.

Chapter 43 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 44 Referenced Standards.

Chapter 44 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 10 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.

Appendix AA Board of Appeals.

Appendix AA contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.

Appendix AB Permit Fees.

Appendix AB provides guidance to jurisdictions for setting appropriate permit fees. This appendix will aid many jurisdictions to assess permit fees that will assist to fairly and properly administer the code. This appendix can be used for informational purposes only or may be adopted when specifically referenced in the adopting ordinance.

Appendix BA Reserved.

Appendix BB Tiny Houses.

For dwelling units that are 400 square feet (37 m [2] ) or less in floor area, excluding lofts, Appendix BB provides relaxed provisions as compared to those in the body of the code. These provisions primarily address reduced ceiling heights for loft areas and specific stair and ladder detail requirements that allow for more compact designs where accessing lofts.

Appendix BC Reserved.

Appendix BD Reserved.

Appendix BE Radon Control Methods.
CRC § 1974-17 High relevance — show source text
E108-2020a|||X||||||||||||||||||||| |CSA||||X|||||||||||||||||||| |DASMA||||X|||||||||||||||||||| |ICC|||X|X|||||||||||||||||||| |IFC-18||||X|||||||||||||||||||| |ISO||||X|||||||||||||||||||| |NFPA|||X|X|||||||||||||||||||| |NFPA 68-13|||X||||||||||||||||||||| |SFM|||X||||||||||||||||||||| |UBC|||X||||||||||||||||||||| |UL||||X|||||||||||||||||||| |UL 790 Edition 9 2022|||X||||||||||||||||||||| |UL 1974-17|||X||||||||||||||||||||| |UL 9540-20|||X||||||||||||||||||||| |UL 9540 Edition 4 2019|||X||||||||||||||||||||| |WDMA||||X||||||||||||||||||||

The state agency does not adopt sections identified with the following symbol: †

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Part IX— Referenced Standards

44 REFERENCED STANDARDS

Notwithstanding California laws and regulations, these referenced standards shall be applicable only to those California Residential Code sections that are adopted.

User notes:

About this chapter: The one- and two-family dwelling code contains numerous references to standards promulgated by other organizations that are used to provide requirements for materials, products and methods of construction. Chapter 44 contains a comprehensive list of all standards that are referenced in this code. These standards, in essence, are part of this code to the extent of the reference to the standard.

This chapter lists the standards that are referenced in various sections of this document. The standards are listed herein by the promulgating agency of the standard, the standard identification, the effective date and title, and the section or sections of this document that reference the standard. The application of the referenced standards shall be as specified in Section R102.4.

ABTG Applied Building Technology Group LLC6300 Enterprise Lane Madison, WI 53719

ANSI/ABTG FS 100—2012 (R2018): Standard Requirements for Wind Pressure Resistance of Foam Plastic Insulation Sheathing Used in Exterior Wall Covering Assemblies

R303.8

ACCA Air Conditioning Contractors of America 1330 Braddock Place, Suite 350 Alexandria, VA 22314

ANSI/ACCA 2 Manual J—2016: Residential Load Calculation

Table R301.2

ACI American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331
CRC § 102.4 Medium relevance — show source text
Chapter 43 Class 2 Remote-control, Signaling and Power-limited Circuits.

Chapter 43 is not adopted in California. See California Electrical Code, Title 24, Part 3.

Chapter 44 Referenced Standards.

Chapter 44 lists all of the product and installation standards and codes that are referenced throughout Chapters 1 through 10 and includes identification of the promulgators and the section numbers in which the standards and codes are referenced. As stated in Section 102.4, these standards and codes become an enforceable part of the code (to the prescribed extent of the reference) as if printed in the body of the code.

Appendix AA Board of Appeals.

Appendix AA contains the provisions for appeal and the establishment of a board of appeals. The provisions include the application for an appeal, the makeup of the board of appeals and the conduct of the appeal process.

Appendix AB Permit Fees.

Appendix AB provides guidance to jurisdictions for setting appropriate permit fees. This appendix will aid many jurisdictions to assess permit fees that will assist to fairly and properly administer the code. This appendix can be used for informational purposes only or may be adopted when specifically referenced in the adopting ordinance.

Appendix BA Reserved.

Appendix BB Tiny Houses.

For dwelling units that are 400 square feet (37 m [2] ) or less in floor area, excluding lofts, Appendix BB provides relaxed provisions as compared to those in the body of the code. These provisions primarily address reduced ceiling heights for loft areas and specific stair and ladder detail requirements that allow for more compact designs where accessing lofts.

Appendix BC Reserved.

Appendix BD Reserved.

Appendix BE Radon Control Methods.

Radon comes from the natural (radioactive) decay of the element radium in soil, rock and water and finds its way into the air. Appendix BE contains requirements to mitigate the transfer of radon gases from the soil into the dwelling. The provisions of this Appendix BE regulate the design and construction of radon-resistant measures intended to reduce the entry of radon gases into the living space of residential buildings.

Appendix BF Patio Covers.

Appendix BF sets forth the regulations and limitations for patio covers. The provisions address those uses permitted in patio cover structures, the minimum design loads to be assigned for structural purposes, and the effect of the patio cover on egress and emergency escape or rescue from sleeping rooms. This appendix also contains the special provisions for aluminum screen enclosures in hurricane-prone regions.

Appendix BG Sound Transmission.

Appendix BG regulates the sound transmission of wall and floor-ceiling assemblies separating dwelling units and townhouse units. Airborne sound insulation is required for walls. Airborne sound insulation and impact sound insulation are required for floor-ceiling assemblies. The provisions in Appendix BG set forth a minimum Sound Transmission Class (STC) rating for common walls and floorceiling assemblies between dwelling units. In addition, a minimum Impact Insulation Class (IIC) rating is also established to limit structureborne sound through common floor-ceiling assemblies separating dwelling units.

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Appendix BH Automatic Vehicular Gates.
CRC § 1.1 Medium relevance — show source text
CBC—25: California Building Code R101.2, R202, R301.1.1, R301.1.3, R301.2.1.1, R301.2.2.1.1, R301.2.2.1.2, R301.3, Table R302.1(1), Table R302.1(2), R302.2.1, R302.2.2, R302.3, R302.15.4, R322.1, R322.3, R324.5, R403.1.8, Table R602.10.3(3), Table R606.12.2.1, R609.2, R905.10.3

CEBC—25: California Existing Building Code [®]

R110.2, N1109.2

CFC—25: California Fire Code [®]

R102.6, R329.2, N1109.2, M2201.7, G2402.3, G2412.2

CWUIC—25: California Wildland-Urban Interface Code

R102.8, R337, R806.1.1, R907.1.1

ICC 400—2022: Standard on the Design and Construction of Log Structures

R301.1.1, R502.1.4, R602.1.4, R703.1, R802.1.3

ICC 500—2020: ICC/NSSA Standard for the Design and Construction of Storm Shelters

R307.1

ICC 600—2020: 2020 Standard for Residential Construction in High-Wind Regions

R301.2.1.1

ICC 1100—2019: Standard for Spray-applied Polyurethane Foam Plastic Insulation

R303.1.1

IPMC—24: International Property Maintenance Code [®]

R102.6

ISO International Organization for Standardization Chemin de Blandonnet 8 Geneva, Switzerland CP 401 - 1214

8336—2009: Fibre-cement Flat Sheets—Product Specification and Test Methods Table R503.2.1.1(1), Table R503.2.1.1(2), Table R602.3(2), Table R702.4.2, R703.10.1, R703.10.2

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REFERENCED STANDARDS

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

13D— 25 : Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes as amended*

R309.1.1, R309.2.1, R309.3.1, R309.3.1.1, R309.3.2.3, R309.3.6.1, R329.6.2.1

*See California Fire Code for amendments

*NFPA 13D, Amended Sections as follows:
CRC § 44-18 Medium relevance — show source text
R303.4

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REFERENCED STANDARDS

276—23: Standard Method of Fire Test for Determining the Heat Release Rate of Roofing Assemblies with Combustible Above- Deck Roofing Components

R906.1

286— 24 : Standard Methods of Fire Tests for Evaluating Contribution of Wall and Ceiling Interior Finish to Room Fire Growth

R302.9.4, R303.6

501—22: Standard on Manufactured Housing

R202

720—15: Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment

R311.7.1, R311.7.2

PCA Portland Cement Association 5420 Old Orchard Road Skokie, IL 60077

100—17: Prescriptive Design of Exterior Concrete Walls for One- and Two-family Dwellings (Pub. No. PCA 100.3)

R301.2.2.5, R404.1.3, R404.1.3.2.1, R404.1.3.2.2, R404.1.3.4, R404.1.4.2, R608.1, R608.2, R608.5.1, R608.9.2, R608.9.3

PTI Post-Tensioning Institute 38800 Country Club Drive Farmington Hills, MI 48331

PTIDC10.5—19: Standard Requirements for Design and Analysis of Shallow Concrete Foundations on Expansive and Stable Soils

R506.2

SBCA Structural Building Components Association 6300 Enterprise Lane Madison, WI 53719

BCSI—2018: Building Component Safety Information—Guide to Good Practice for Handling, Installing, Restraining & Bracing of Metal Plate Connected Wood Trusses

R502.12.2, R802.10.3

CFS-BCSI—(updated June 2016): Cold-formed Steel Building Component Safety Information (CFSBCSI)—Guide to Good Practice for Handling, Installing & Bracing of Cold-formed Steel Trusses

R505.1.3, R804.3.6

SFM State of California Department of Forestry and Fire Protection, Office of the State Fire Marshal, P.O. Box 944246, Sacramento, CA

944246-2460

SFM—12-3: Releasing Systems for Security Bars in Dwellings

SFM 12-7A-1: Exterior Wall Siding and Sheathing

SFM 12-7A-2: Exterior Window

SFM 12-7A-3: Horizontal Protection Underside

SFM 12-7A-4: Decking

SFM 12-7A-4A: Decking Alternate Method A

(The Office of the State Fire Marshal standards referred to above are found in the California Code of Regulations, Title 24, Part 12.)

TMS The Masonry Society 105 South Sunset Street, Suite Q Longmont, CO 80501

402—2022: Building Code Requirements for Masonry Structures
CRC § 1.11. Medium relevance — show source text
41—2023|X|||X|X|||X|X|X|X|X||X|X|||||||||| |ASTM A615—15 22||||||||||X||||||||||||||| |ICC A117.1—2017||||†|†|†||||||||||||||||||| |ICC CBC—25||||||||||X||||||||||||||| |NFPA 72—24|||X||||||||||||||||||||||

The 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.

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16 REFERENCED STANDARDS

User notes:

About this chapter: This code contains numerous references to standards that are used to regulate materials and methods of construction. Chapter 16 contains a comprehensive list of all standards that are referenced in the code, including the appendices. The standards are part of the code to the extent of the reference to the standard. Compliance with the referenced standard is necessary for compliance with this code. By providing specifically adopted standards, the construction and installation requirements necessary for compliance with the code can be readily determined. The basis for code compliance is, therefore, established and available on an equal basis to the building code official, contractor, designer and owner.

This chapter lists the standards that are referenced in various sections of this document. The standards are listed herein by the promulgating agency of the standard, the standard identification, the effective date and title, and the section or sections of this document that reference the standard. The application of the referenced standards shall be as specified in Section 102.4 , or California Administration Division 1, as applicable. [OSHPD 1] Reference to other chapters. In addition to the code sections referenced, the standards listed in this chapter are applicable to the respective code sections in Chapters 3A, 4A and 5A.

ACI American Concrete Institute, 38800 Country Club Drive, Farmington Hills, MI 48331-3439

562—21: Assessment, Repair, and Rehabilitation of Existing Concrete Structures—Code Requirements

405.1.1

ASCE/SEI American Society of Civil Engineers Structural Engineering Institute, 1801 Alexander Bell Drive, Reston, VA 20191-4400

7—1988: Minimum Design Loads and Associated Criteria for Buildings and Other Structures

503.12, 706.3.2

7—1993: Minimum Design Loads and Associated Criteria for Buildings and Other Structures

503.12, 706.3.2

7—1995: Minimum Design Loads and Associated Criteria for Buildings and Other Structures

503.12, 706.3.2

7—1998: Minimum Design Loads and Associated Criteria for Buildings and Other Structures

503.12, 706.3.2

7—2002: Minimum Design Loads and Associated Criteria for Buildings and Other Structures

503.12, 706.3.2

7—2005: Minimum Design Loads and Associated Criteria for Buildings and Other Structures

503.12, 706.3.2

7—2010: Minimum Design Loads and Associated Criteria for Buildings and Other Structures
CRC § 9-4 Medium relevance — show source text
R904 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4

R905 Requirements for Roof Coverings . . . . . . . . . . . . . . . . 9-4

R906 Roof Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19

R907 Rooftop-Mounted Photovoltaic Panel Systems . . . 9-19

R908 Reroofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19

R909 Roof Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-20

CHAPTER 10 CHIMNEYS AND FIREPLACES . . . . . . . . . . . .10-3

R1001 Masonry Fireplaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3

R1002 Masonry Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6

R1003 Masonry Chimneys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7

R1004 Factory-Built Fireplaces. . . . . . . . . . . . . . . . . . . . . . . . 10-12

R1005 Factory-Built Chimneys . . . . . . . . . . . . . . . . . . . . . . . . 10-12

R1006 Exterior Air Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-12

Part IV—Energy Conservation. . . . . . . . . . . . . . . . . . . . . . . .11-1

Part V—Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-1

Part VI—Fuel Gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24-1

Part VII—Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-1

Part VIII—Electrical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34-1

Part IX— Referenced Standards . . . . . . . . . . . . . . . . . . . . . .44-3

CHAPTER 44 REFERENCED STANDARDS . . . . . . . . . . . . . .44-3
CRC § 1801.1 Medium relevance — show source text
Chapter 16 Stationary Power Plants. This chapter provides minimum requirements for stationary fuel cell power plants. A fuel cell is a device that produces electricity by a chemical reaction. Fuel cells have been used mostly for satellites. However, the costs of fuel cells have decreased to a point where they are now economically attainable. With the increase in electricity costs, fuel cells are being considered as an alternative for producing electricity.

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FORMAT OF THE UNIFORM MECHANICAL CODE

Chapter 17 Geothermal Energy Systems and Ambient Temperature Loops. Chapter 17 regulates the design, installation, construction, and location of geothermal energy systems and ambient temperature loops (ATLs). This chapter provides the minimum safety requirements for various types of geothermal systems, including building systems coupled with a ground-heat exchangers, submerged heat exchangers using water-based fluid as a heat transfer medium, and groundwater (well). For ease of use and clarification on the applicability of geothermal provisions, Chapter 17 is divided into five parts pertaining to general provisions for all types of geothermal systems, closed-loop systems, open-loop systems, direct-exchange (DX) systems, and ambient temperature loops. For district ambient temperature loops, including those utilizing multiple hybrid systems, Part I through Part V are applicable.

In order to properly design a geothermal system, it is important to know the seasonal variation in the soil temperature, as well as the soil’s inherent capability to store and transmit heat, namely its heat capacity and thermal conductivity. In addition, a properly designed heat pump distribution system is essential for the distribution of geothermal energy.

Materials for piping and tubing must meet the working temperature and pressure of the system. Furthermore, materials must be compatible with the transfer medium to prevent deformation, bursting, or any chemical action between the material and the transfer medium. Approved materials for indoor piping, fittings, and accessories that are a part of a groundwater system as well as the allowable joining methods for piping or tubing are provided for application and enforcement purposes.

Chapter 18 Referenced Standards. Chapter 18 provides two comprehensive tables with referenced standards. The standards listed in Table 1801.1 are applied as indicated in the applicable reference section(s). A list of additional approved standards, publications, practices, and guides that are not referenced in specific sections appear in Table 1801.2.

Referenced standards set forth specific details of accepted practices, materials specifications, or test methods in many specialized applications. Standards provide an efficient method of conveying complex information and specifications on the performance requirements for materials, products, systems, application, and installation. The manner and purpose for a standard’s use and, in turn, code compliance, must be definitive in all references to the standard. If the standard is intended to be a requirement for judging code compliance, the code must state its intent for use. The standard should adequately address a defined need and at the same time specify the minimum performance requirements, technical characteristics and methods of testing, and required test results.

The referenced standards tables are organized in a manner that makes it easy to find specific standards in alphabetical order, and by acronym of the publishing agency of the standard. The tables list the title of the standard, the edition, and any addenda. Contact information for each publishing agency is provided at the end of the chapter.

CRC § 5.1 Medium relevance — show source text

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FLOORS

R507.5.1 Deck beam bearing. Beams and individual beam plies of built-up beams shall be continuous between bearing locations and continuous across bearing locations supporting beam cantilevers. Beams shall be permitted to cantilever beyond bearing locations up to one-fourth of the actual beam span. The ends of beams shall have not less than 1 [1] / 2 inches (38 mm) of bearing length on wood or metal and not less than 3 inches (76 mm) of bearing length on concrete or masonry for the entire width of the beam.

R507.5.2 Deck beam connection to supports. Deck beams shall be connected to supporting members to prevent lateral displacement. Deck beam connections to wood posts shall be in accordance with Figures R507.5.2(1)) and R507.5.2(2). Manufactured post-to-beam connectors shall be sized for the post and beam sizes. Bolts shall have washers under the head and nut.

FIGURE R507.5.2(1)—DECK BEAM TO DECK POST

For SI: 1 inch = 25.4 mm.

FIGURE R507.5.2(2)—NOTCHED POST-TO-BEAM CONNECTION

MINIMUM 2" MINIMUM 2½"

SINGLE-PLY BEAM MULTIPLE-PLY BEAM

(2) ½" DIAMETER THROUGH-BOLTS

OR APPROVED

EQUIVALENT

CONNECTOR

POST NOTCH

FOR FULL-BEAM

BEARING

≥ 2½" MIN.

≥ ¾"

For SI: 1 inch = 25.4 mm.

5-36 2025 CALIFORNIA RESIDENTIAL CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

FLOORS

R507.6 Deck joists. Maximum allowable spans for wood deck joists, as shown in Figure R507.6, shall be in accordance with Table R507.6. The maximum joist spacing shall be limited by the decking materials in accordance with Table R507.7.

FIGURE R507.6—TYPICAL DECK JOIST SPANS

Col2	Col11	Col12	Col13





M


	JOISTSPAN MEASURED BEAM JOISTS HANGER EACH END POST (BEYOND)	JOISTSPAN MEASURED BEAM JOISTS HANGER EACH END POST (BEYOND)	JOISTSPAN MEASURED BEAM JOISTS HANGER EACH END POST (BEYOND)

JOIST BEAM POST (BEYOND) JOIST SPAN	Col2	Col3
JOIST JOIST SPAN BEAM POST (BEYOND)

OPTIONAL OPTIONAL

CANTILEVER CANTILEVER

JOISTS ON FREE-STANDING DECK WITH DROPPED BEAM

CENTERLINE TO CENTERLINE

CRC § 1.11. Medium relevance — show source text
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|||||||||||||X|||X||||||||| |Adopt Entire Chapter as
amended (amended
sections listed below)|X||X|X|X|||X|X|X|X|X||X|X|||||||||| |Adopt only those sections
that are listed below||||||||||||||||||||||||| |Chapter / Section||||||||||||||||||||||||| |ASCE/SEI 7—2016||||||||||X|X|X||X|X|||||||||| |ASCE/SEI 7—2022||||||||X|X|X|X|X||X|X|||||||||| |ASCE/SEI 41—2013||||||||||X||||||||||||||| |ASCE/SEI 41—2023|X|||X|X|||X|X|X|X|X||X|X|||||||||| |ASTM A615—15 22||||||||||X||||||||||||||| |ICC A117.1—2017||||†|†|†||||||||||||||||||| |ICC CBC—25||||||||||X||||||||||||||| |NFPA 72—24|||X||||||||||||||||||||||

The 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.

2025 CALIFORNIA EXISTING BUILDING CODE 16-1

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

16-2 2025 CALIFORNIA EXISTING BUILDING CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

16 REFERENCED STANDARDS

User notes:

About this chapter: This code contains numerous references to standards that are used to regulate materials and methods of construction. Chapter 16 contains a comprehensive list of all standards that are referenced in the code, including the appendices. The standards are part of the code to the extent of the reference to the standard. Compliance with the referenced standard is necessary for compliance with this code. By providing specifically adopted standards, the construction and installation requirements necessary for compliance with the code can be readily determined. The basis for code compliance is, therefore, established and available on an equal basis to the building code official, contractor, designer and owner.
CRC § 10-12 Medium relevance — show source text
R1004 Factory-Built Fireplaces. . . . . . . . . . . . . . . . . . . . . . . . 10-12

R1005 Factory-Built Chimneys . . . . . . . . . . . . . . . . . . . . . . . . 10-12

R1006 Exterior Air Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-12

Part IV—Energy Conservation. . . . . . . . . . . . . . . . . . . . . . . .11-1

Part V—Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-1

Part VI—Fuel Gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24-1

Part VII—Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-1

Part VIII—Electrical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34-1

Part IX— Referenced Standards . . . . . . . . . . . . . . . . . . . . . .44-3

CHAPTER 44 REFERENCED STANDARDS . . . . . . . . . . . . . .44-3

APPENDIX AA BOARD OF APPEALS. . . . . . . . . . APPENDIX AA-3

AA101 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX AA-3

APPENDIX AB PERMIT FEES. . . . . . . . . . . . . . . . APPENDIX AB-3

AB101 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX AB-3

APPENDIX AC RESERVED . . . . . . . . . . . . . . . . . . APPENDIX AC-1

APPENDIX BA RESERVED . . . . . . . . . . . . . . . . . . APPENDIX BA-1

APPENDIX BB TINY HOUSES . . . . . . . . . . . . . . . APPENDIX BB-3

BB101 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX BB-3

BB102 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX BB-3

BB103 Ceiling Height . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX BB-3

BB104 Lofts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .APPENDIX BB-3

Frequently asked questions

Where exactly in the CRC do I look for the official standard edition and the CRC sections that depend on it?

Look in Chapter 44 — Referenced Standards; each entry shows the standard ID, edition/date, title, and the CRC section(s) that reference it. See § 44.

If Chapter 44 lists a standard but a CRC section seems silent, which controls?

The CRC section that references the standard and § R102.4 control; the standard applies only to the degree the CRC section incorporates it. See § R102.4.

Can I use a newer edition of an external standard than the one listed in Chapter 44?

Not unless the CRC section, a California amendment, or an adopting jurisdiction explicitly allows it. Chapter 44 records the edition the CRC references — use that edition unless the Code says otherwise.

Are state‑agency standards listed in Chapter 44?

Yes; Chapter 44 notes state agency standards and includes adoption/matrix notes directing you to agency regulations or other Title‑24 parts when applicable.

Where are referenced standards used for enforcement?

Referenced standards become part of the enforceable requirements only where a CRC section references them and per the application rules in § R102.4.

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Related in the CRC

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Application & scope of referenced standards

California Residential Code