CEBC · California Existing Building Code
What is the difference between a change of use and a change of occupancy classification?
If your building’s formal occupancy group changes (for example, storage to mercantile), that’s a change of occupancy classification and Sections 1002–1011 apply (including sprinkler/alarm triggers in §1011). If the activity changes but the occupancy group stays the same, it’s a change of use and you follow Chapter 6 and Sections 1002–1010. Always confirm with the code official and expect a certificate of occupancy if the classification changes.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
A change of use is work that alters how a space is used but stays within the same occupancy group; that work must comply with Chapter 6 and Sections 1002–1010. This requirement is stated in § 1001.2.1. A change of occupancy classification is when the building’s occupancy classification itself changes (one group to another); that triggers the broader set of requirements in § 1001.2.2 and brings Section 1011 into play. See § 1001.2.1 and § 1001.2.2 for the controlling language.
The single most important rule: if the occupancy CLASSIFICATION changes, apply Sections 1002–1011 (more stringent); if only the USE changes but the CLASS stays the same, apply Chapter 6 and Sections 1002–1010.
Requirements in detail
Key definitions (first-use)
- Change of occupancy — includes any change in occupancy classification, any change in purpose or level of activity, or a change of use where the new situation requires a greater degree of safety than the existing condition. See the CEBC definitions for change of occupancy.
- Change of use — a change in how a space is used within the same occupancy group when that change alters which code requirements apply. See the CEBC definition for change of use.
What sections apply
- If the classification does NOT change (use changes within same group): work must conform to Chapter 6 and Sections 1002–1010 — § 1001.2.1.
- If the classification DOES change: Sections 1002–1011 apply (note the addition of 1011, the Change of Occupancy Classification section) — § 1001.2.2.
Decision matrix (quick reference)
| Decision dimension | Value / condition | What the CEBC requires | Code reference |
|---|---|---|---|
| Occupancy classification change? | No (same occupancy group) | Follow Chapter 6 and Sections 1002–1010 (apply appropriate alterations/use provisions). | § 1001.2.1 |
| Occupancy classification change? | Yes (group changes or classification within group changes) | Follow Sections 1002–1011 (includes Section 1011 requirements such as fire protection thresholds). | § 1001.2.2 |
| Fire protection trigger | New classification requires sprinkler/alarm per CBC Chapter 9 | Install required systems within the area of change and adjoining areas not separated by a firewall. | § 1011.2.1 and § 1011.2.1.1 |
| Partial change of occupancy | Only a portion changes | Section 1011 (and 1011.1) governs partial changes; apply separation requirements per § 1011. | § 1001.2.2.1 and § 1011.1 |
| Certificate of occupancy | When classification changes to a different occupancy | A certificate of occupancy is required when a change results in a different occupancy classification. | § 1001.3 |
How Section 1011 elevates requirements when a classification changes
- Section 1011.1 makes Sections 1002–1011 applicable to change-of-classification situations.
- § 1011.2.1 requires automatic sprinkler systems where the CBC Chapter 9 threshold for the new occupancy requires sprinklers; the sprinkler requirement extends to the area of change and any building areas not separated by a fire wall.
- § 1011.2.2 requires fire alarm/detection where required for the new occupancy per CBC Chapter 9 (following California Fire Code/Chapter 11/Section 907).
Exceptions & special cases
- Partial changes: if only part of a building changes classification and that part is separated with required fire barriers/horizontal assemblies, only the separated portion may need to comply with the new requirements — see § 1001.2.2.1 and Section 1011.
- Small-area exception: several provisions (e.g., structural, seismic, snow/wind exceptions) allow relief when the new occupancy area is less than 10% of building area — check the specific sections (see e.g., 1006.2 and related exceptions).
- Where the new occupancy reduces hazard: the CEBC permits certain relaxations subject to code official approval when the new occupancy is less hazardous than the old one (see Section 506.1 in the related prescriptive chapter).
Common mistakes
- Treating any change in activity as automatically only a "use" change. The CEBC treats a change in purpose or level of activity that increases required safety as a change of occupancy; don’t conflate “use” with “classification.” See the CEBC definitions for change of occupancy and change of use.
- Forgetting sprinkler/alarm thresholds: if the new occupancy classification would require sprinklers or alarms under CBC Chapter 9, those systems are required for the affected area and adjoining areas not separated by a firewall per § 1011.2.1 and § 1011.2.2.
- Assuming partial changes never trigger building-wide upgrades — cumulative changes and adjacency (no firewall) can require broader compliance. The CEBC specifically considers the cumulative effect of occupancy changes.
- Not getting a certificate of occupancy: when the occupancy classification changes to a different classification, a certificate of occupancy is required per § 1001.3.
Worked example — concrete scenario with numbers
Scenario: A 10,000 ft² single-story warehouse (Group S) is converted to a retail store (Group M) over 3,500 ft² of the floor area.
Step 1 — Is the occupancy classification changing? Yes. Group S (storage) → Group M (mercantile) is a change of occupancy classification. Apply § 1001.2.2 (Sections 1002–1011).
Step 2 — Sprinkler trigger: Suppose CBC Chapter 9 requires sprinklers for Group M at this building size or configuration. Because classification changed, § 1011.2.1 requires an automatic sprinkler system in the 3,500 ft² area and in building areas not separated by a firewall (the CEBC requires sprinklers to extend to non-separated areas). If the 3,500 ft² space is NOT separated by a firewall from the remaining 6,500 ft², sprinklers may be required for the whole building.
Step 3 — Partial-area exception check: The CEBC contains a “less than 10%” exception for some structural and load triggers; here 3,500 ft² is 35% of the building, so the small-area exception does not apply. (If the new area had been < 10% of 10,000 ft² = 1,000 ft², some exceptions might be available.)
Step 4 — Certificate and other requirements: Because the classification changed, issue a certificate of occupancy only after compliance with the applicable CEBC Sections has been demonstrated (see § 1001.3). Expect to evaluate means of egress (Section 1011 / Table 1011.5), structural live loads (Section 1006.1), fire alarms (Section 1011.2.2), and plumbing/electrical adjustments appropriate to the new use.
Related provisions
- § 1001.2.1 — Change of use (Chapter 6; Sections 1002–1010 apply).
- § 1001.2.2 — Change of occupancy classification (Sections 1002–1011 apply).
- § 1001.3 — Certificate of occupancy required when classification changes.
- § 1011.1 — General applicability of Section 1011 to occupancy classification changes.
- § 1011.2.1 — Automatic sprinkler system requirements when change of occupancy classification triggers CBC Chapter 9 thresholds.
- § 1011.2.2 — Fire alarm/detection system requirements on change of occupancy classification.
- § 1003.1 — Building elements and materials in portions undergoing change of occupancy classification.
- § 1004.1 — Fire protection requirements when change of occupancy occurs or when fire protection thresholds differ.
- Section 506 (Change of Occupancy in Prescriptive Compliance Method) — related rules when using Chapter 5 prescriptive approach.
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 1001.2.1 High relevance — show source text
1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.
1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.
1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.
1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .
SECTION 1002—SPECIAL USE AND OCCUPANCY
1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.
1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.
SECTION 1003—BUILDING ELEMENTS AND MATERIALS
1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1004—FIRE PROTECTION
1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:
- A building or portion thereof undergoes a change of occupancy.
- A building or portion thereof undergoes a change of occupancy and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or portion thereof.
SECTION 1005—MEANS OF EGRESS
1005.1 General. Means of egress in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1006—STRUCTURAL
[BS] 1006.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 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.
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[BS] 1006.2 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 and 1609 of the California Building Code for the new risk category.
CEBC § 1001.1 High relevance — show source text
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User notes:
About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.
SECTION 1001—GENERAL
1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.
1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.
1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.
1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.
1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.
1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .
SECTION 1002—SPECIAL USE AND OCCUPANCY
1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.
1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.
SECTION 1003—BUILDING ELEMENTS AND MATERIALS
1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1004—FIRE PROTECTION
CEBC § 1.11. High relevance — show source text
Note: Building shall have the same meaning as defined in Health and Safety Code Sections 17920 and 18908 for the applications speci- fied in Section 1.11.
BUILDING OFFICIAL. [BSC, DSA-SS, DSA-SS/CC] The individual within the agency or organization charged with responsibility for compliance with the requirements of this code. For some agencies this person is termed the “enforcement agent.”
BUILDING OFFICIAL. [HCD 1, HCD 2] [OSHPD 1, 1R, 2, 4 & 5] The officer or other designated authority charged with the administration and enforcement of this code, or a duly authorized representative.
CHANGE IN FUNCTION. [OSHPD 1, 1R, 2, 4 & 5] See California Building Code Section 1224.3.
[A] CHANGE OF OCCUPANCY. Any of the following shall be considered as a change of occupancy where the current California Building Code requires a greater degree of safety, accessibility, structural strength, fire protection, means of egress, ventilation or sanitation than is existing in the current building or structure:
- Any change in the occupancy classification of a building or structure.
- Any change in the purpose of, or a change in the level of activity within, a building or structure.
- A change of use.
[A] CHANGE OF USE. A change in the use of a building or a portion of a building, within the same group classification, for which there is a change in application of the code requirements.
[A] CODE OFFICIAL. The officer or other designated authority charged with the administration and enforcement of this code.
[HCD 1 & HCD 2] [OSHPD 1, 1R, 2, 4 & 5] “Code Official” shall mean “Building Official” as defined in this code.
CRITICAL CARE AREA. [OSHPD 1] See California Administrative Code Chapter 6.
[BS] DANGEROUS. Any building, structure or portion thereof that meets any of the conditions described below shall be deemed dangerous:
- The building or structure has collapsed, has partially collapsed, has moved off its foundation or lacks the necessary support of the ground.
- There exists a significant risk of collapse, detachment or dislodgement of any portion, member, appurtenance or ornamentation of the building or structure under permanent, routine or frequent loads; under actual loads already in effect; or under snow, wind, rain, flood, earthquake aftershock or other environmental loads when such loads are imminent.
[A] DEFERRED SUBMITTAL. Those portions of the design that are not submitted at the time of the application and that are to be submitted to the code official within a specified period.
[BS] DISPROPORTIONATE EARTHQUAKE DAMAGE. A condition of earthquake-related damage where both of the following occur:
- The 0.3-second spectral acceleration at the building site for the earthquake in question, as estimated by one of the following, is less than 30 percent of the mapped acceleration parameter S S : 1.1. The United States Geological Survey’s algorithm for the data point closest to the site. 1.2. As determined from peer-reviewed seismograph records from the site or from locations closer to the site than the algorithm-provided data points.
CEBC § 1.8.2. Medium relevance — show source text
4. See Health and Safety Code Section 18201 for “Approved” as applied to Mobilehome Parks as referenced in Section 1.8.2. 5. See Health and Safety Code Section 18862.1 for “Approved” as applied to Special Occupancy Parks as referenced in Section 1.8.2.
[A] APPROVED AGENCY. An established and recognized organization that is regularly engaged in conducting tests, furnishing inspection services or furnishing product evaluation or certification where such organization has been approved by the code official.
[A] BUILDING. Any structure utilized or intended for supporting or sheltering any use or occupancy.
Exception: [HCD 1, HCD 2 & HCD 1-AC] For applications listed in Section 1.8.2 regulated by the Department of Housing and Commu- nity Development, “Building” shall not include the following: 1. Any mobilehome as defined in Health and Safety Code Section 18008. 2. Any manufactured home as defined in Health and Safety Code Section 18007. 3. Any commercial modular as defined in Health and Safety Code Section 18001.8 or any special purpose commercial modular as defined in Section 18012.5.
4. Any recreational vehicle as defined in Health and Safety Code, Section 18010.
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DEFINITIONS
5. Any multifamily manufactured home as defined in Health and Safety Code Section 18008.7.
For additional information, see Health and Safety Code Section 18908.
Note: Building shall have the same meaning as defined in Health and Safety Code Sections 17920 and 18908 for the applications speci- fied in Section 1.11.
BUILDING OFFICIAL. [BSC, DSA-SS, DSA-SS/CC] The individual within the agency or organization charged with responsibility for compliance with the requirements of this code. For some agencies this person is termed the “enforcement agent.”
BUILDING OFFICIAL. [HCD 1, HCD 2] [OSHPD 1, 1R, 2, 4 & 5] The officer or other designated authority charged with the administration and enforcement of this code, or a duly authorized representative.
CHANGE IN FUNCTION. [OSHPD 1, 1R, 2, 4 & 5] See California Building Code Section 1224.3.
[A] CHANGE OF OCCUPANCY. Any of the following shall be considered as a change of occupancy where the current California Building Code requires a greater degree of safety, accessibility, structural strength, fire protection, means of egress, ventilation or sanitation than is existing in the current building or structure:
- Any change in the occupancy classification of a building or structure.
- Any change in the purpose of, or a change in the level of activity within, a building or structure.
- A change of use.
[A] CHANGE OF USE. A change in the use of a building or a portion of a building, within the same group classification, for which there is a change in application of the code requirements.
[A] CODE OFFICIAL. The officer or other designated authority charged with the administration and enforcement of this code.
CEBC § 1007.1 Medium relevance — show source text
3 Exception 3|X|||||||||||||||||||||||| |1007||||†|†|||||||||||||||||||| |1007.1|||X|||||||||||||||||||||| |1009.2 – 1009.4||||†|†|||||||||||||||||||| |1011.2.1|||X|||||||||||||||||||||| |1011.2.2|||X|||||||||||||||||||||| |1011.4||||†|†|||||||||||||||||||| |1011.5.1|||X|||||||||||||||||||||| |1011.5.1 Exception 8||||†|†|||||||||||||||||||| |Table 1011.5|||X|||||||||||||||||||||| |1011.5.2|||X|||||||||||||||||||||| |1011.5.2 Exception 2||||†|†|||||||||||||||||||| |1011.5.4|||X|||||||||||||||||||||| |1011.5.5|||X|||||||||||||||||||||| |1011.6.1 Exception 1||||†|†|||||||||||||||||||| |1011.7.1 Exception||||†|†|||||||||||||||||||| |1011.8.2|||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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10 CHANGE OF OCCUPANCY
User notes:
About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.
SECTION 1001—GENERAL
1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.
1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.
CEBC § 10-5 Medium relevance — show source text
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1011.5 Means of egress, general. Hazard categories in regard to life safety and means of egress shall be in accordance with Table 1011.5.
TABLE 1011.5—MEANS OF EGRESS HAZARD CATEGORIES Col2 RELATIVE HAZARD OCCUPANCY CLASSIFICATIONS 1 (Highest Hazard) H (Not Allowed) 2 I-2; I-3; I-4_(Not Allowed)_ 3 A; E; M; R-1; R-2; R-4 4 B; F-1; R-3; R-4, S-1 5 (Lowest Hazard) F-2; S-2; U 1011.5.1 Means of egress for change to a higher-hazard category. Where a change of occupancy classification is made to a higher-hazard category (lower number) as shown in Table 1011.5, the means of egress shall comply with the requirements of Chapter 10 of the California Building Code .
Exceptions:
Stairways shall be enclosed in compliance with the applicable provisions of Section 903.1.
Existing stairways including handrails and guards complying with the requirements of Chapter 9 shall be permitted for continued use subject to approval of the code official.
Any stairway replacing an existing stairway within a space where the pitch or slope cannot be reduced because of existing construction shall not be required to comply with the maximum riser height and minimum tread depth requirements.
Existing corridor walls constructed on both sides of wood lath and plaster in good condition or [1] / 2 -inch-thick (12.7 mm) gypsum wallboard shall be permitted. Such walls shall either terminate at the underside of a ceiling of equivalent construction or extend to the underside of the floor or roof next above.
Existing corridor doorways, transoms and other corridor openings shall comply with the requirements in Sections 804.7.1, 804.7.2 and 804.7.3.
Existing dead-end corridors shall comply with the requirements in Section 804.8.
An operable window complying with Section 1011.5.6 shall be accepted as an emergency escape and rescue opening.
In Group R-2.1 and I-2 facilities, required guards enclosing the occupiable roof areas shall be permitted to be greater than 48 inches (1219 mm) above the surface of the occupiable roof where the occupants, because of clinical needs, require restraint or containment as part of a function of a psychiatric or cognitive treatment area.
1011.5.2 Means of egress for change of use to an equal or lower-hazard category. Where a change of occupancy classification is made to an equal or lesser-hazard category (higher number) as shown in Table 1011.5, existing elements of the means of egress shall comply with the requirements of Section 905 for the new occupancy classification. Newly constructed or configured means of egress shall comply with the requirements of Chapter 10 of the California Building Code .
Exceptions:
CEBC § 1.11. Medium relevance — show source text
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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13 PERFORMANCE COMPLIANCE METHODS
Not adopted by the State of California (May be available for adoption by local ordinance. See Section 1.1.11.) (See Section 104.11 for consideration of alternative means of compliance.)
User notes:
About this chapter: Chapter 13 allows for existing buildings to be evaluated so as to show that alterations, while not meeting new construction requirements, will improve the current existing situation. Provisions are based on a numerical scoring system involving 21 various safety parameters and the degree of code compliance for each issue.
SECTION 1301—GENERAL
1301.1 Scope. The provisions of this chapter shall apply to the alteration, addition and change of occupancy of existing structures, including historic structures, as referenced in Section 301.3.3. The provisions of this chapter are intended to maintain or increase the current degree of public safety, health and general welfare in existing buildings while permitting, alteration, addition and change of occupancy without requiring full compliance with Chapters 6 through 12, except where compliance with the prescriptive method of Chapter 5 or the work area method of other provisions of this code is specifically required in this chapter.
1301.1.1 Compliance with other methods. Alterations, additions and changes of occupancy to existing structures shall comply with the provisions of this chapter or with one of the methods provided in Section 301.3.
SECTION 1302—APPLICABILITY
1302.1 General. Existing buildings in which there is work involving additions, alterations or changes of occupancy shall be made to conform to the requirements of this chapter or the provisions of Chapters 6 through 12. The provisions of Sections 1302.1.1 through 1302.1.6 shall apply to existing occupancies that will continue to be, or are proposed to be, in Groups A, B, E, F, I-2, M, R and S. These provisions shall also apply to Group U occupancies where such occupancies are undergoing a change of occupancy or a partial change in occupancy with separations in accordance with Section 1302.1.2. These provisions shall not apply to buildings with occupancies in Group H, I-1, I-3 or I-4.
1302.1.1 Change in occupancy. Where an existing building is changed to a new occupancy classification and this section is applicable, the provisions of this section for the new occupancy shall be used to determine compliance with this code.
1302.1.2 Partial change in occupancy. Where a portion of the building is changed to a new occupancy classification and that portion is separated from the remainder of the building with fire barrier or horizontal assemblies having a fire-resistance rating as required by Table 508.4 of the International Building Code or Section R302 of the International Residential Code for the separate occupancies, or with approved compliance alternatives, the portion changed shall be made to conform to the provisions of this section. Only the portion separated shall be required to be evaluated for compliance.
CEBC § 1.10.1 Medium relevance — show source text
Chapter 5A Prescriptive Compliance Method.
Chapter 5A provides details for the prescriptive compliance method for alteration, addition and change of occupancy of existing build- ings and structures regulated by the Department of Health Care Access and Information/Office of Statewide Hospital Planning and Development, which include hospitals and correctional treatment centers (applications listed in Sections 1.10.1 (OSHPD 1).
Chapter 6 Classification of Work.
Chapter 6 provides an overview of the Work Area Method and defines the different classifications of work including alterations, change of occupancy, additions and historic buildings. Detailed requirements for all of these are given in subsequent Chapters 7 through 11.
Chapter 7 Alterations—Level 1.
Chapter 7 provides the technical requirements for those existing buildings that undergo Level 1 alterations as described in Section 602, which includes replacement or covering of existing materials, elements, equipment or fixtures using new materials for the same purpose. This chapter is distinguished from Chapters 8 and 9 by only involving replacement of building components with new components with no reconfiguration of space.
Chapter 8 Alterations—Level 2.
A Level 2 alteration is an alteration involving space reconfiguration that could be up to and including 50 percent of the area of the building or addition of a new building system. Level 2 alterations also include the extension or addition of any system or equipment. The purpose of Chapter 8 is to provide detailed requirements and provisions to identify the required improvements in the existing building elements, means of egress, fire protection, structural systems, energy efficiency, and other building systems include electrical, mechanical and plumbing when a building is being altered.
Chapter 9 Alterations—Level 3.
Chapter 9 provides the technical requirements for those existing buildings that undergo Level 3 alterations. Level 3 alterations are those involving alterations that cover 50 percent of the aggregate area of the building. Under certain situations, this chapter also intends to improve the safety of certain building features beyond the work area and in other parts of the building where no alteration work might be taking place.
Chapter 10 Change of Occupancy.
The purpose of Chapter 10 is to address existing buildings that are subject to a change of occupancy. This chapter is an assembly of requirements to upgrade safety without having to comply fully as a new building. A change of occupancy classification is considered a change of occupancy, however, it will involve a higher level of regulation since the use of the building has made a more significant change.
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Chapter 11 Additions.
Chapter 11 provides the requirements for additions, which are considered new construction. The requirements focus on safely integrating the addition with the existing building. This includes issues such as limiting the overall height and area of the building where the addition is not separated by a fire wall.
Chapter 12 Historic Buildings —Reserved
Chapter 12 is not adopted by the State of California. Historic buildings and structures shall comply with Part 8, Title 24, California Code of Regulations.
Chapter 13 Performance Compliance Methods.
Chapter 13 allows for existing buildings to be evaluated to show that alterations or a change of occupancy, while not meeting new construction requirements, will provide a level of safety to demonstrate compliance. Provisions are based on a numerical scoring system involving 21 safety parameters where, when evaluated, such buildings must meet a minimum overall safety score.
CEBC § 310.2 Medium relevance — show source text
1|||X|||||||||||||||||||||| |310.2|||X|X||||||||||||||||||||| |310.3|||X|X||||||||||||||||||||| |310.3.1|||X|||||||||||||||||||||| |310.3.2|||X|||||||||||||||||||||| |310.4|||X|X||||||||||||||||||||| |310.4.1|||X|||||||||||||||||||||| |310.4.2|||X|X|X|||||||||||||||||||| |310.5|||X|||||||||||||||||||||| |310.6|||X|||||||||||||||||||||| |313|||X|||||||||||||||||||||| |314|||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 BUILDING CODE 3-1
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OCCUPANCY CLASSIFICATION AND USE
User notes:
About this chapter: Chapter 3 provides the criteria by which buildings and structures are classified into use groups and occupancies. Through the balance of the code, occupancy classification is fundamental in the setting of features of construction; occupant safety requirements, especially building limitations; means of egress; fire protection systems; and interior finishes.
ICC code development note: Code change proposals to sections preceded by the designation [F] will be considered by the IFC code development committee meeting during the 2024 (Group A) Code Development Cycle. All other code change proposals will be considered by a code development committee meeting during the 2025 (Group B) Code Development Cycle.
SECTION 301—SCOPE
301.1 General. The provisions of this chapter shall control the classification of all buildings and structures as to occupancy and use. Different classifications of occupancy and use represent varying levels of hazard and risk to building occupants and adjacent properties.
SECTION 302—OCCUPANCY CLASSIFICATION AND USE DESIGNATION
302.1 Occupancy classification. Occupancy classification is the formal designation of the primary purpose of the building, structure or portion thereof. Structures shall be classified into one or more of the occupancy groups specified in this section based on the nature of the hazards and risks to building occupants generally associated with the intended purpose of the building or structure. An area, room or space that is intended to be occupied at different times for different purposes shall comply with all applicable requirements associated with such potential multipurpose. Structures containing multiple occupancy groups shall comply with Section 508. Where a structure is proposed for a purpose that is not specified in this section, such structure shall be classified in the occupancy it most nearly resembles based on the fire safety and relative hazard. Occupiable roofs shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard, and shall comply with Section 503.1.4.
- Assembly (see Section 303): Groups A-1, A-2, A-3, A-4 and A-5.
- Business (see Section 304): Group B.
CEBC § 1006.3 Medium relevance — show source text
Exception: Where the area of the new occupancy is less than 10 percent of the building area. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 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 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
Reserved.
Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.
[BS] 1006.4 Access to Risk Category IV. Any structure that provides operational access to an adjacent structure assigned to Risk Category IV as the result of a change of occupancy shall itself comply with Sections 1608 and 1609 of the California Building Code and Section 304.3.1 of this code. Where operational access to Risk Category IV is less than 10 feet (3048 mm) from either an interior lot line or from another structure, access protection from potential falling debris shall be provided.
SECTION 1007—ELECTRICAL
1007.1 Special occupancies. Where the occupancy of an existing building or part of an existing building is changed to one of the following special occupancies as described in the California Electrical Code, the electrical wiring and equipment of the building or portion thereof that contains the proposed occupancy shall comply with the applicable requirements of the California Electrical Code :
Hazardous locations.
Commercial garages, repair and storage.
Aircraft hangars.
Gasoline dispensing and service stations.
Bulk storage plants.
Spray application, dipping and coating processes.
Reserved.
Places of assembly.
Theaters, audience areas of motion picture and television studios, and similar locations.
Motion picture and television studios and similar locations.
Motion picture projectors.
Agricultural buildings.
1007.2 Unsafe conditions. Where the occupancy of an existing building or part of an existing building is changed, all unsafe conditions shall be corrected without requiring that all parts of the electrical system comply with the California Electrical Code .
1007.3 Service upgrade. Where the occupancy of an existing building or part of an existing building is changed, electrical service shall be upgraded to meet the requirements of the California Electrical Code for the new occupancy.
CEBC § 1011.5.6. Medium relevance — show source text
- 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.
- Where the replacement of the window is part of a change of occupancy, it shall comply with Section 1011.5.6.
505.3.1 Control devices. Window opening control devices or fall prevention devices complying with ASTM F2090 shall be permitted for use on windows required to provide emergency escape and rescue openings. After operation to release the control device allowing the window to fully open, the control device shall not reduce the net clear opening area of the window unit. Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys or tools.
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PRESCRIPTIVE COMPLIANCE METHOD
505.4 Bars, grilles, covers or screens. Bars, grilles, covers, screens or similar devices are permitted to be placed over emergency escape and rescue openings, bulkhead enclosure or window wells that serve such openings, provided all of the following conditions are met:
- The minimum net clear opening size complies with the code that was in effect at the time of construction.
- Such devices shall be releasable or removable from the inside without the use of a key, tool or force greater than that which is required for normal operation of the escape and rescue opening.
- Where such devices are installed, they shall not reduce the net clear opening of the emergency escape and rescue openings .
- Smoke alarms shall be installed in accordance with Section 907.2.11 of the California Building Code .
SECTION 506—CHANGE OF OCCUPANCY
506.1 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 code 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 of the California Building Code unless required by Section 506.5.
506.1.1 Change in the character of use. A change of occupancy with no change of occupancy classification shall not be made to any structure that will subject the structure to any special provisions of the applicable California Codes, without approval of the code official. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
506.1.2 Change in function. [OSHPD 1R, 2, 4 and 5] A change in function shall require compliance with all the functional require- ments for new construction in the California Building Code, including requirements in Sections 1224, 1225, 1226, 1227 and 1228.
CEBC § 1004.1 Medium relevance — show source text
SECTION 1004—FIRE PROTECTION
1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:
- A building or portion thereof undergoes a change of occupancy.
- A building or portion thereof undergoes a change of occupancy and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or portion thereof.
SECTION 1005—MEANS OF EGRESS
1005.1 General. Means of egress in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1006—STRUCTURAL
[BS] 1006.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 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.
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CHANGE OF OCCUPANCY
[BS] 1006.2 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 and 1609 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. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 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 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
Reserved.
Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.
Frequently asked questions
What is the shortest test to decide whether it’s a “use” change or an “occupancy classification” change?
If the building’s formal occupancy GROUP (A, B, E, F, H, I, M, R, S, U, etc.) changes, it is a change of occupancy classification and § 1001.2.2 applies; if the group stays the same but the activity within that group changes code application, treat it as a change of use under § 1001.2.1.
Do I always need sprinklers when I change occupancy?
No — sprinklers are required where the new occupancy would require them under CBC Chapter 9. But when a change of occupancy classification occurs and Chapter 9 would require sprinklers for the new occupancy, § 1011.2.1 requires sprinkler installation in the affected area and adjoining areas not separated by a firewall.
Can I convert a small part of a building without triggering the full set of change-of-classification rules?
Sometimes. Several CEBC provisions allow relief where the new occupancy area is less than 10% of building area for specific structural or load requirements — check the applicable exceptions and consult the code official.
Do I need a new certificate of occupancy?
Yes — when a change of occupancy results in a different occupancy classification as determined by the California Building Code, a certificate of occupancy is required per § 1001.3.
Who decides whether a proposed change is a “use” or a “classification” change?
The code official has authority to determine applicability and approve equivalent approaches or exceptions; where ambiguity exists, get the code official’s determination and plan review. See the definitions and administration sections for the role of the code official.
More in California Existing Building Code
- Administration and Definitions (Scope, enforcement, code official duties, definitions)
- Provisions for All Compliance Methods (general requirements that apply to all compliance options; Chapter 3 / 3A)
- Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)
- Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
- Repairs (Chapter 4 — repair-specific rules for materials, means of egress, structural, MEP, etc.)
- Alterations — Level 1, Level 2, Level 3 (technical requirements for each alteration level; Chapters 7–9)
- Change of Occupancy and Additions (requirements for occupancy changes and additions; Chapters 10–11)
- Compliance Methods — Prescriptive, Work Area, Performance (Chapters 5, 6–11, 13)
- Relocated Buildings (requirements for buildings moved or relocated; Chapter 14)
- Construction Safeguards (site safety, means of egress and life-safety during construction; Chapter 15)
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