History of the California Building Standards Code

Title 24 of the California Code of Regulations

The 2022 edition of Title 24 went into effect on January 1, 2023. Parts 2, 2.5, 9 and 10 are based on ICC’s 2021 international model codes: IBC, IRC, IFC and IEBC. Part 3 is based on NFPA’s 2020 NEC. Parts 4 and 5 are based on IAPMO’s 2021 UMC and UPC. Parts 1, 6, 8, 11 and 12 are California codes.

The 2019 edition of Title 24 went into effect on January 1, 2020. Parts 2, 2.5, 9 and 10 are based on ICC’s 2018 international model codes: IBC, IRC, IFC and IEBC. Part 3 is based on NFPA’s 2017 NEC. Parts 4 and 5 are based on IAPMO’s 2018 UMC and UPC. Parts 1, 6, 8, 11 and 12 are California codes.

The 2016 edition of Title 24 went into effect on January 1, 2017. Parts 2, 2.5, 9 and 10 were based on ICC’s 2015 international model codes: IBC, IRC, IFC and IEBC. Part 3 was based on NFPA’s 2014 NEC. Parts 4 and 5 were based on IAPMO’s 2015 UMC and UPC. Parts 1, 6, 8, 11 and 12 are California codes.

The 2013 edition of Title 24 went into effect on January 1, 2014, with the exception of Part 6, which went into effect July 1, 2014. Parts 2, 2.5, 9 and 10 were based on ICC’s 2012 international model codes: IBC, IRC, IFC and IEBC. Part 3 was based on NFPA’s 2011 NEC. Parts 4 and 5 were based on IAPMO’s 2012 UMC and UPC. Parts 1, 6, 8, 11 and 12 are California codes.

  • The California Building Standards Commission (CBSC) delayed the effective date of the California Energy Code, Part 6, and Chapter 10 of the California Administrative Code, Part 1, and affected energy provisions only in the California Green Building Standards Code (CALGreen), Part 11, from January 1, 2014 to July 1, 2014. This was due to unanticipated delays in developing related compliance software. Request CBSC Information Bulletin 13-07 for details.

The 2010 edition of Title 24 went into effect on January 1, 2011 with the exception of the California Energy Code, Part 6, which went into effect on July 1, 2011. This was because the California Energy Commission, which has the authority to adopt the regulations within Part 6, was using a different code adoption cycle than CBSC. They have since aligned their cycle with CBSC’s so that users of Title 24 do not have to keep track of multiple effective dates.

Parts 2, 2.5, 9 and 10 were based on ICC’s 2009 international model codes: IBC, IRC, IFC and IEBC. Part 3 was based on NFPA’s 2008 NEC. Parts 4 and 5 were based on IAPMO’s 2009 UMC and UPC. Parts 1, 6, 8, 11 and 12 are California codes.

  • In this edition, some voluntary California Green Building Standards Code (CALGreen) measures were made mandatory. More restrictive voluntary codes were published as tier options which local jurisdictions could choose to adopt and enforce.

  • Also, this is the first edition with a Part 2.5, California Residential Code, adopting the International Residential Code for detached one- and two-family dwellings, efficiency units, and townhouses up to three stories. Other residential occupancies remain subject to Part 2.

The 2007 edition of Title 24 went into effect on January 1, 2008. Parts 2, 9 and 10 were based on ICC’s 2006 international model codes: IBC, IFC and IEBC. Part 3 was based on NFPA’s 2005 NEC. Parts 4 and 5 were based on IAPMO’s 2006 UMC and UPC. Parts 1, 6, 7, 8, 11 and 12 are California codes. This edition had some major changes: 

  • The name of Part 1 changed from “California Building Standards Administrative Code” to “California Administrative Code.” This should not be confused with the old name of the California Code of Regulations, which was the California Administrative Code until changed by 1987 legislation (Ch. 1375, Statutes of 1987) effective on January 1, 1988.

  • First edition where Part 2 is based on ICC’s International Building Code.

  • Part 7 had only a one-page notice that elevator standards are published in Title 8, Industrial Relations, California Code of Regulations. Thereafter, Part 7 of Title 24 is vacant. AB 3000 (Ch. 1124 of 2002 Statutes) amended California Health and Safety Code Section 18909(j) to exclude elevator standards promulgated by the Occupational Safety and Health Standards Board from the definition of building standards.

  • First edition where Part 9 is based on ICC’s International Fire Code.

  • The name of Part 10 changed from “California Code for Building Conservation,” which was based on the Uniform Code for Building Conservation published by ICBO, to the “California Existing Building Code,” which is based on ICC’s IEBC.

  • The 2008 California Green Building Standards Code, also known as CALGreen (Part 11 of Title 24), is published in January 2009 and goes into effect the following August. This edition of CALGreen is mostly voluntary.

Note:  Until the 2006 Triennial Adoption Cycle, there were different publication and effective dates within Title 24 due to the many different adoption cycles and model code publication dates, and due to debate about which model codes to use in California. CBSC realized this was challenging for all users of the code, and therefore made a concerted effort to coordinate cycles so that all parts of Title 24 can be published within one edition with the same effective date. This was accomplished with the 2007 edition.

 

The 2003 Triennial Code Adoption Cycle did not result in a complete 2004 edition of Title 24. Only the 2004 California Electrical Code, Part 3 (based on the 2002 NEC), was published with an effective date of August 1, 2005. Later, the 2005 California Energy Code, Part 6, was published with an effective date of October 1, 2005. Other than Parts 3 and 6, the 2001 edition of Title 24 remained the applicable code.

 

Note:  The 1997 Uniform Building Code (UBC) was the last edition published by the ICBO, which had merged with the ICC. This edition continued as the basis for the California Building Code (Part 2 of Title 24) from the 1998 edition of Title 24 through the 2001 edition, and which remained in effect until superseded by the 2007 edition based on the 2006 IBC. This was because of CBSC decisions that the 2000 and 2003 International Building Code editions published by ICC, and the 2003 Building Construction and Safety Code published by NFPA, were not appropriate replacements for the 1997 UBC. This was the era when the controversy over the International Code Council (ICC) model building code and the National Fire Protection Association (NFPA) model building code was unresolved and thus there were no 2004 editions of the California Building, Fire or Existing Building Codes (or related and dependent Title 24 parts).

 

The 2001 edition of Title 24 went into effect on November 1, 2002. Part 2 was based on the 1997 UBC by ICBO; Part 3 was based on the 1999 NEC by NFPA; Parts 4 and 5 were based on the 2000 UMC and UPC by IAPMO; Part 9 was based on the 2000 UFC by Western Fire Chiefs Association (WFCA); and, Part 10 was based on the 1997 Uniform Code for Building Conservation also ICBO. Parts 1, 6, 7, 8 and 12 were California codes that also went into effect on November 1.

The 1998 edition of Title 24 went into effect on July 1, 1999. Part 2 was based on the 1997 UBC by ICBO; Part 3 was based on the 1996 NEC by NFPA; Parts 4 and 5 were based on the 1997 UMC and UPC by IAPMO; Part 9 was based on the 1997 UFC by WFCA; and, Part 10 was based on the 1997 Uniform Code for Building Conservation also by ICBO. Parts 1, 6, 7, 8 and 12 were California codes that also went into effect on July 1.

The 1995 edition of Title 24 went into effect on various dates due to California law regulating how model codes were to be adopted within one year of their publication. Part 2 was based on the 1994 UBC by ICBO; Part 3 was based on the 1993 NEC by NFPA; Parts 4 and 5 were based on the 1994 UMC and UPC by IAPMO; Part 9 was based on the 1994 UFC by WFCA; and, Part 10 was based on the 1994 Uniform Code for Building Conservation also by ICBO. Parts 1, 6, 7, 8 and 12 were California codes. Parts 2, 3, 5, 8, 9 and 10 went into effect on January 1, 1996. Part 4 went into effect on February 19, 1996.  Parts 1, 7 and 12 had effective dates that varied by chapters or sections. The approval, publication and effective dates for these parts are detailed in the History Note Appendices for each chapter or section. The published Part 6 directed users to call the California Energy Commission for the effective date.

For Title 24 history prior to 1995, contact CBSC at (916) 263-0916 or cbsc@dgs.ca.gov, or visit one of many State Document Depository Libraries.

Acronyms and Abbreviations

Model Code Developers:

IAPMO—International Association of Plumbing and Mechanical Officials

ICBO—International Conference of Building Officials (became part of ICC in 1994)

ICC—International Code Council

NFPA—National Fire Protection Association

Model Codes:

IBC—International Building Code

IEBC—International Existing Building Code

IFC—International Fire Code

IRC—International Residential Code

NEC—National Electrical Code

UMC—Uniform Mechanical Code

UPC—Uniform Plumbing Code

Parts of Title 24:

Part 1—California Administrative Code

Part 2—California Building Code, Volumes 1 and 2

Part 2.5—California Residential Code

Part 3—California Electrical Code

Part 4—California Mechanical Code

Part 5—California Plumbing Code

Part 6—California Energy Code

Part 7—Vacant

Part 8—California Historical Building Code

Part 9—California Fire Code

Part 10—California Existing Building Code

Part 11—California Green Building Standards Code, aka CALGreen

Part 12—California Referenced Standards Code

View Current Title 24 Edition