Section 506A — CHANGE OF OCCUPANCY

506 A .1 Compliance. A change of occupancy shall not be made in any building unless that building is made to comply with the requirements of the California Building Code for the use or occupancy. Changes of occupancy in a building or portion thereof shall be such that the existing building is not less complying with the provisions of this code than the existing building or structure was prior to the change. Subject to the approval of the building official, changes of occupancy shall be permitted without complying with all of the requirements of this code for the new occupancy, provided that the new occupancy is less hazardous, based on life and fire risk, than the existing occupancy.

Exception: The building need not be made to comply with Chapter 16 A of the California Building Code unless required by Section 506 A .5.

506 A .1.1 Change in function . A change in function shall require compliance with all the functional requirements for new construc- tion in the California Building Code, including requirements in California Building Code Section 1224. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.

Exception: Minimum room clearances, areas and dimensions may meet the requirements of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.

506 A .2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.

506 A .3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.

506 A .4 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031.1 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:

An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.

506 A .5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.

506 A .5.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 A of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 A of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.

Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads need not comply with this section.

506 A .5.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 A and 1609 A of the California Building Code for the new risk category.

Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.

506 A .5.3 Seismic loads (seismic force-resisting system). Where a change of occupancy results in a building being assigned to a higher risk category, the lateral force-resisting system of the building shall comply with the California Building Code Section 1613A or Section 304A.3.4 of this code for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 A of the California Building Code or shall comply with ASCE 41 -23 using an objective of Operational nonstructural performance with the BSE-1N earthquake hazard level.

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5A-8 2025 CALIFORNIA EXISTING BUILDING CODE

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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE

CHAPTER 6 – CLASSIFICATION OF WORK

(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			DSA			OSHPD							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				X	X
Adopt Entire Chapter as amended (amended sections listed below)			X
Adopt only those sections that are listed below
Chapter / Section
601.1			X
601.1.1			X
607.1			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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6-2 2025 CALIFORNIA EXISTING BUILDING CODE

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