CHBC · California Historical Building Code

When are occupancy separations, floor‑area and height limits relaxed for historic buildings?

Q: When does the CHBC treat a building as “qualified historical” for these relaxations?

The CHBC applies only to a qualified historical building or property as defined elsewhere in Chapter 8; the relaxations in §§ 8‑302.3–8‑302.5 apply only to those qualifying buildings. The specific qualification language is outside the quoted excerpts here; consult the CHBC definitions in Chapter 8‑2 for the full criteria.

Q: If I add sprinklers only to parts of the building, do I get the CHBC relaxations?

Most CHBC relaxations require the building to be provided with an automatic sprinkler system throughout . Partial sprinkling typically will not trigger the full relaxations unless a specific provision (e.g., § 8‑302.5.1 for high‑rise scenarios) permits selective application with required fire barriers and alarm systems. §§ 8‑302.3, 8‑302.5.1 .

Q: Can I raise a historic building higher than it ever was if I meet fire‑protection conditions?

No. § 8‑302.5 allows height not to be limited because of construction type but still caps it at the building’s historical design . You may not exceed the historical height/number‑of‑stories under that section.

Q: If a required separation is reduced to 1 hour, what must the door assemblies be?

Openings must be protected by assemblies of not less than 3/4‑hour and doors with automatic‑closing devices must respond to products of combustion (not only to heat). § 8‑302.3 .

If your building is a qualified historic property, the CHBC lets you relax certain separation, area and height limits — mostly when you add modern life‑safety systems. Installing an automatic sprinkler system throughout is the single most effective way to reduce or remove required occupancy separations and to allow larger one‑story floor areas; height still cannot exceed the building’s historical design. See **§§ 8‑302.3, 8‑302.4, 8‑302.5, 8‑302.5.1** for the specific conditions and required supplemental systems.

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Last reviewed: July 6, 2026

What the code requires — in plain English

The California Historical Building Code allows targeted relaxations of occupancy separations, maximum floor area, and height/number‑of‑stories limits for qualified historical buildings when preserving historical character would otherwise be unduly restrictive. Key allowances: occupancy separations can be reduced or omitted when the building is fully sprinklered; a one‑story historic building is normally limited to 15,000 square feet unless exceptions apply; and height is not limited by construction type so long as it does not exceed the building’s historical design. See § 8-302.3, § 8-302.4, § 8-302.5, and § 8-302.5.1 for the controlling language.

The single most important practical rule: if you provide an automatic sprinkler system throughout a qualified historical building, many separation and area restrictions are significantly relaxed under the CHBC.

Requirements in detail

Occupancy separations (what can be reduced or omitted)

If a required occupancy separation rating is greater than one hour, it may be reduced to a 1‑hour fire‑resistive separation provided:
- All openings in that separation are protected by not less than 3/4‑hour assemblies, and
- The building has an automatic sprinkler system throughout installed per § 8-410.2 (referenced in the CHBC). Doors with automatic‑closing devices must respond to products of combustion, not just heat. § 8-302.3.
If the required separation is 1 hour, that separation may be omitted when the building is fully sprinklered. § 8-302.3.

Decision‑relevant table — occupancy separations

Decision item	Relaxation allowed	Required condition(s)	Code Reference
Required separation > 1 hr	Reduced to 1‑hour with 3/4‑hr protected openings	Automatic sprinkler throughout; self‑closing/automatic‑closing doors that respond to smoke products	§ 8-302.3
Required separation = 1 hr	Separation may be omitted	Automatic sprinkler throughout	§ 8-302.3

Maximum floor area (one‑story buildings)

A one‑story qualified historical building may have up to 15,000 sq ft unless a greater area is already permitted under the regular code. § 8-302.4.
Exceptions that allow unlimited floor area without fire‑resistive area separation walls:
1. If the building is provided with an automatic sprinkler throughout, OR
2. For residential occupancies of two stories or less, if the building has a complete fire alarm and annunciation system and the exiting system conforms to the regular code. § 8-302.4.

Decision‑relevant table — floor‑area limits

Type of building	Default max floor area	How to exceed / remove limit	Code Reference
One‑story qualified historical building	15,000 sq ft	Unlimited if fully sprinklered, or for 1–2 story residential with full fire alarm/annunciation + regular‑code exiting	§ 8-302.4
Multistory qualified historical building	Follow regular code (no CHBC increase)	N/A	§ 8-302.4

Maximum height and high‑rise rules

Height and number of stories are not limited because of construction type, so long as the building’s height/number of stories does not exceed its historical design. In short, you cannot increase height beyond what historically existed. § 8-302.5.
Special provision for high‑rise occupancies: for occupancies B, F‑1, F‑2 or S in high‑rise buildings, where floors are located more than 75 feet above the lowest level having building access, the CHBC permits only the stories over 75 ft to be sprinklered (instead of the whole building) if all of the following are met:
1. Building construction type and exits conform to regular code;
2. A complete building fire alarm and annunciation system is installed; and
3. A fire barrier is provided between the sprinklered and non‑sprinklered floors. § 8-302.5.1.

Decision‑relevant table — height / high‑rise

Decision item	CHBC allowance	Required condition(s)	Code Reference
Height limits due to construction type	Not limited by construction type (cannot exceed historical design)	Historical design cap applies	§ 8-302.5
High‑rise (floors > 75 ft)	Only floors over 75 ft may be sprinklered (instead of full building)	Construction/exits per regular code; full building fire alarm/annunciation; fire barrier between sprinklered & nonsprinklered floors	§ 8-302.5.1

Exceptions & special cases

The CHBC explicitly ties relaxations to fire protection features (sprinklers, fire alarm/annunciation, fire barriers) and to not exceeding the building’s historical design. If those conditions are not met, you revert to the CHBC limits or the regular code as applicable. §§ 8-302.3, 8-302.4, 8-302.5, 8-302.5.1.
For multistory historic buildings (including basements/cellars), area limits follow the regular code, not the CHBC one‑story exception. § 8-302.4.
The CHBC references other CHBC fire‑protection chapters (e.g., § 8-410.2 for sprinkler requirements) — compliance with those provisions is part of meeting the CHBC relaxations. § 8-302.3.

If a specific requirement or definition used above does not appear in the provided CHBC excerpt, it is noted in the text above rather than invented.

Common mistakes

Assuming sprinklers alone solve every code issue: sprinklers enable many relaxations, but additional systems (fire alarm/annunciation, fire barriers, compliant exits) are required in some exceptions — read § 8-302.4 and § 8-302.5.1 carefully.
Treating multistory historic buildings like one‑story exceptions: multistory buildings follow the regular code for area unless another provision specifically applies. § 8-302.4.
Increasing historical height beyond what historically existed: CHBC allows no increase above the building’s historical design under § 8-302.5.
Forgetting door device requirements: when reductions rely on automatic‑closing doors, those devices must respond to products of combustion, not just heat, per § 8-302.3.

Worked example — concrete scenario with numbers

Scenario: You own a one‑story qualified historical commercial building that historically was 20,000 sq ft. You want to continue commercial use without building new fire‑resistive area walls.

CHBC baseline: one‑story historic buildings are limited to 15,000 sq ft unless an exception applies. § 8-302.4.
Option A — install an automatic sprinkler system throughout: If you do, the CHBC allows unlimited floor area without fire‑resistive area separation walls. That would permit the existing 20,000 sq ft to remain without adding separation walls. § 8-302.4.
Option B — you don’t want sprinklers: you would need to comply with the 15,000 sq ft limit (i.e., provide area separation or other regular‑code remedies) because the CHBC exception for unlimited area requires either sprinklers or the residential two‑story scenario with fire alarm + regular exits. § 8-302.4.

Another example (occupancy separation): a mixed‑occupancy historic building has a required separation of 1.5 hours between two occupancies. If you install automatic sprinklers throughout, you can reduce that to 1 hour with 3/4‑hour protected openings (self‑closing/automatic). If the required separation were only 1 hour, sprinklers throughout could allow omitting the separation entirely. § 8-302.3.

Related provisions (CHBC sections to review)

§ 8-302.3 — Occupancy separations (primary occupancy‑separation relaxations).
§ 8-302.4 — Maximum floor area (15,000 sq ft one‑story limit and exceptions).
§ 8-302.5 — Maximum height (not limited by construction type; cannot exceed historical design).
§ 8-302.5.1 — High‑rise building provisions (75‑ft rule for selective sprinkling).
§ 8-410.2 — (Referenced) Automatic sprinkler system requirements used to qualify for CHBC relaxations.
§ 8-302.6 — Fire‑resistive construction (see Chapter 8‑4 reference).
§ 8-303.6 and § 8-503 — Other CHBC sections referenced for light/ventilation and escape/rescue provisions.

Code references

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

CHBC § 8-3 High relevance — show source text
TREATMENT. An act of work to carry out preservation, restoration, stabilization, rehabilitation or reconstruction.

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8-3 USE AND OCCUPANCY

SECTION 8-301 — PURPOSE AND SCOPE

8-301.1 Purpose. The purpose of the CHBC is to provide regulations for the determination of occupancy classifications and conditions of use for qualified historical buildings or properties.

8-301.2 Scope. Every qualified historical building or property for which a permit or approval has been requested shall be classified prior to permit issuance according to its use or the character of its occupancy in accordance with the regular code and applicable provisions of this chapter.

SECTION 8-302 — GENERAL

8-302.1 Existing use. The use or character of occupancy of a qualified historical building or property, or portion thereof, shall be permitted to continue in use regardless of any period of time in which it may have remained unoccupied or in other uses, provided such building or property otherwise conforms to all applicable requirements of the CHBC.

8-302.2 Change in occupancy. The use or character of the occupancy of a qualified historical building or property may be changed from or returned to its historical use or character, provided the qualified historical building or property conforms to the requirements applicable to the new use or character of occupancy as set forth in the CHBC. Such change in occupancy shall not mandate conformance with new construction requirements as set forth in regular code.

8-302.3 Occupancy separations. Required occupancy separations of more than one hour may be reduced to one-hour fire-resistive construction with all openings protected by not less than three-fourths-hour fire-resistive assemblies of the self-closing or automatic-closing type when the building is provided with an automatic sprinkler system throughout the entire building in accordance with Section 8-410.2. Doors equipped with automatic-closing devices shall be of a type which will function upon activation of a device which responds to products of combustion other than heat.

Required occupancy separations of one hour may be omitted when the building is provided with an automatic sprinkler system throughout.

8-302.4 Maximum floor area. Regardless of the use or character of occupancy, the area of a one-story qualified historical building or property may have, but shall not exceed, a floor area of 15,000 square feet (1393.5 m [2] ) unless such an increase is otherwise permitted in regular code. Multistory qualified historical buildings (including basements and cellars) shall be in accordance with regular code requirements.

Exception: Historical buildings may be unlimited in floor area without fire-resistive area separation walls:
1. When provided with an automatic sprinkler, or
2. Residential occupancies of two stories or less when provided with a complete fire alarm and annunciation system and where the exiting system conforms to regular code.
8-302.5 Maximum height. The maximum height and number of stories of a qualified historical building or property shall not be limited because of construction type, provided such height or number of stories does not exceed that of its historical design.
CHBC § 8-302.3 High relevance — show source text
8-302.3 Occupancy separations. Required occupancy separations of more than one hour may be reduced to one-hour fire-resistive construction with all openings protected by not less than three-fourths-hour fire-resistive assemblies of the self-closing or automatic-closing type when the building is provided with an automatic sprinkler system throughout the entire building in accordance with Section 8-410.2. Doors equipped with automatic-closing devices shall be of a type which will function upon activation of a device which responds to products of combustion other than heat.

Required occupancy separations of one hour may be omitted when the building is provided with an automatic sprinkler system throughout.

8-302.4 Maximum floor area. Regardless of the use or character of occupancy, the area of a one-story qualified historical building or property may have, but shall not exceed, a floor area of 15,000 square feet (1393.5 m [2] ) unless such an increase is otherwise permitted in regular code. Multistory qualified historical buildings (including basements and cellars) shall be in accordance with regular code requirements.

Exception: Historical buildings may be unlimited in floor area without fire-resistive area separation walls:
1. When provided with an automatic sprinkler, or
2. Residential occupancies of two stories or less when provided with a complete fire alarm and annunciation system and where the exiting system conforms to regular code.
8-302.5 Maximum height. The maximum height and number of stories of a qualified historical building or property shall not be limited because of construction type, provided such height or number of stories does not exceed that of its historical design.

8-302.5.1 High-rise buildings. Occupancies B, F-1, F-2 or S in high-rise buildings with floors located more than 75 feet above the lowest floor level having building access may be permitted with only the stories over 75 feet provided with an automatic fire sprinkler system if:
1. The building construction type and the exits conform to regular code, and
2. A complete building fire alarm and annunciation system is installed, and
3. A fire barrier is provided between the sprinklered and nonsprinklered floors.
8-302.6 Fire-resistive construction. See Chapter 8-4.

8-302.7 Light and ventilation. Existing provisions for light and ventilation which do not, in the opinion of the enforcing agency, constitute a safety hazard may remain. See Section 8-303.6 for residential requirements. See Section 8-503 for Escape or Rescue Windows and Doors.

SECTION 8-303 — RESIDENTIAL OCCUPANCIES

8-303.1 Purpose. The purpose of this section is to provide regulations for those buildings designated as qualified historical buildings or properties and classified as residential occupancies. The CHBC requires enforcing agencies to accept any reasonably equivalent alternative to the regular code when dealing with qualified historical buildings and properties.

8-303.2 Intent. The intent of the CHBC is to preserve the integrity of qualified historical buildings and properties while maintaining a reasonable degree of protection of life, health and safety for the occupants.

8-303.3 Application and scope. The provisions of this section shall apply to all qualified historical buildings used for human habitation. Those dwelling units intended only for display, or public use with no residential use involved, need not comply with the requirements of this section.

8-303.4 Fire escapes. See Chapter 8-5.

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California Historical Building Code High relevance — show source text
IN THOUSANDS OF BTU PER HOUR**|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR| |VENT
HEIGHT
_H _
(feet)|CONNECTOR
RISE
_R _
(feet)|FAN|FAN|NAT|FAN|FAN|NAT|FAN|FAN|NAT| |VENT
HEIGHT
_H _
(feet)|CONNECTOR
RISE
_R _
(feet)|Min|Max|Max|Min|Max|Max|Min|Max|Max| |6|1
2
3|262
271
279|293
331
361|183
219
247|325
334
344|373
422
462|234
281
316|447
458
468|463
524
574|286
344
385| |8|1
2
3|285
293
302|316
353
381|191
228
256|352
360
370|403
450
489|244
292
328|481
492
501|502
560
609|299
355
400| |10|1
2
3|302
311
320|335
369
398|196
235
265|372
381
391|429
473
511|252
302
339|506
517
528|534
589
637|308
368
413| |15|1
2
3|312
321
331|380
411
438|208
248
281|397
407
418|482
522
557|266
317
360|556
568
579|596
646
690|324
387
437| |20|1
2
3|306
317
326|425
453
476|217
259
294|390
400
412|538
574
607|276
331
375|546
558
570|664
709
750|336
403
457| |30|1
2
3|296
307
316|497
521
542|230
274
309|378
389
400|630
662
690|294
349
394|528
541
555|779
819
855|358
425
482| |50|1
2
CHBC § 8-301 High relevance — show source text
Section

8-301 Purpose and Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8-302 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

8-303 Residential Occupancies. . . . . . . . . . . . . . . . . . . . . . . . . 5

CHAPTER 8-4 FIRE PROTECTION. . . . . . . . . . . . . . . . . . . . . . . 7

Section

8-401 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . . 7

8-402 Fire-resistive Construction . . . . . . . . . . . . . . . . . . . . . . . 7

8-403 Interior Finish Materials. . . . . . . . . . . . . . . . . . . . . . . . . . 7

8-404 Wood Lath and Plaster. . . . . . . . . . . . . . . . . . . . . . . . . . . 7

8-405 Occupancy Separation . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8-406 Maximum Floor Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

8-407 Vertical Shafts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

8-408 Roof Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8-409 Fire Alarm Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8-410 Automatic Sprinkler Systems. . . . . . . . . . . . . . . . . . . . . 8 8-411 Other Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8-412 High-rise Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

CHAPTER 8-5 MEANS OF EGRESS . . . . . . . . . . . . . . . . . . . . . . 9

Section

8-501 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . . 9 8-502 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8-503 Escape or Rescue Windows and Doors. . . . . . . . . . . . 10 8-504 Railings and Guardrails . . . . . . . . . . . . . . . . . . . . . . . . . 10
CHBC § 8-1 High relevance — show source text
CONTENTS

CHAPTER 8-1 ADMINISTRATION . . . . . . . . . . . . . . . . . . . . . . . 1

Section

8-101 Title, Purpose and Intent. . . . . . . . . . . . . . . . . . . . . . . . . 1 8-102 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 8-103 Organization and Enforcement . . . . . . . . . . . . . . . . . . . 1 8-104 Review and Appeals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 8-105 Construction Methods and Materials . . . . . . . . . . . . . . 2

8-106 SHBSB Rulings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

CHAPTER 8-2 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Section

8-201 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

CHAPTER 8-3 USE AND OCCUPANCY . . . . . . . . . . . . . . . . . . . 5

Section

8-301 Purpose and Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 8-302 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

8-303 Residential Occupancies. . . . . . . . . . . . . . . . . . . . . . . . . 5

CHAPTER 8-4 FIRE PROTECTION. . . . . . . . . . . . . . . . . . . . . . . 7

Section

8-401 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . . 7

8-402 Fire-resistive Construction . . . . . . . . . . . . . . . . . . . . . . . 7

8-403 Interior Finish Materials. . . . . . . . . . . . . . . . . . . . . . . . . . 7

8-404 Wood Lath and Plaster. . . . . . . . . . . . . . . . . . . . . . . . . . . 7

8-405 Occupancy Separation . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8-406 Maximum Floor Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
CHBC § 1001.1 Medium relevance — show source text
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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.

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
CHBC § 3.2 Medium relevance — show source text
301 A .3.2 Nonconforming buildings . Alterations, additions and changes of occupancy to existing buildings or structures designed in accordance with the Pre-1973 building code complying with Section 304A.3.1 and the applicable requirements herein shall be considered in compliance with the provisions of this code.

301 A .3.3 Performance- based method. Alterations, additions and changes of occupancy to existing buildings or structures complying with Sections 304A.3.4 and 304A.3.5 of this code shall be considered in compliance with the provisions of this code.

301 A .4 Moved structures . Structures moved into or within the jurisdiction shall comply with the provisions of the California Building Code for new structures.

301A.5 Reserved.

301A.6 Peer review requirements. Peer review requirements shall comply with California Building Code Section 1617A.1.41.

301A.7 Earthquake monitoring instruments for existing buildings. Earthquake monitoring instrumentation of existing buildings shall comply with Section 313A.

301A.8 Compliance alternatives for services/systems and utilities . Compliance alternatives for services/systems and utilities shall comply with Section 310A.

301A.9 Compliance alternatives for means of egress. Means of egress through existing buildings shall comply with Section 311A.

301A.10 Removal of hospital buildings from general acute care services. Removal of hospital buildings from General Acute Care Services shall comply with Section 312A.

SECTION 302 A —GENERAL PROVISIONS

302 A .1 Dangerous conditions. The code official shall have the authority to require the elimination of conditions deemed dangerous.

302 A .2 Additional codes. Alterations, repairs, additions and changes of occupancy to, or relocation of, existing buildings and struc- tures shall comply with the provisions for alterations, repairs, additions and changes of occupancy or relocation, respectively, in the California Fire Code, California Mechanical Code, California Plumbing Code and California Electrical Code. Where provisions of the other codes conflict with provisions of this chapter, the provisions of this chapter shall take precedence.

302 A .2.1 Additional codes in health care. In existing Group I-2 occupancies, ambulatory health care facilities, outpatient clinics and hyperbaric facilities, alterations, repairs, additions and changes of occupancy to, or relocation of, existing buildings and structures shall also comply with NFPA 99.

302 A .3 Existing materials and equipment. Materials and equipment already in use in a building in compliance with requirements or approvals in effect at the time of their erection or installation shall be permitted to remain in use unless determined by the code official to be unsafe in accordance with California Building Code Section 116.

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PROVISIONS FOR ALL COMPLIANCE METHODS
CHBC § 308.4.2 Medium relevance — show source text
308.4.2 Condition 2. This occupancy condition shall include buildings in which free movement is allowed from sleeping areas and any other occupied smoke compartment to one or more other smoke compartments. Egress to the exterior is impeded by locked exits.

308.4.3 Condition 3. This occupancy condition shall include buildings in which free movement is allowed within individual smoke compartments, such as within a residential unit composed of individual sleeping units and group activity spaces, where

2025 CALIFORNIA BUILDING CODE 3-13

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OCCUPANCY CLASSIFICATION AND USE

egress is impeded by remote-controlled release of means of egress from such a smoke compartment to another smoke compartment.

308.4.4 Condition 4. This occupancy condition shall include buildings in which free movement is restricted from an occupied space. Remote-controlled release is provided to permit movement from sleeping units, activity spaces and other occupied areas within the smoke compartment to other smoke compartments.

308.4.5 Condition 5. This occupancy condition shall include buildings in which free movement is restricted from an occupied space. Staff-controlled manual release is provided to permit movement from sleeping units, activity spaces and other occupied areas within the smoke compartment to other smoke compartments.

308.4.6 Condition 6. This occupancy condition shall include buildings containing only one temporary holding facility with six or fewer persons under restraint or security where the building is protected throughout with a monitored automatic sprinkler system installed in accordance with Section 903.3.1.1 and where the temporary holding facility is protected throughout with an automatic fire alarm system with notification appliances. A Condition 6 building shall be permitted to be classified as a Group B occupancy.

308.4.7 Condition 7. This occupancy condition shall include buildings containing only one temporary holding facility with nine or less persons under restraint or security where limited to the first or second story, provided the building complies with Section 408.1.2.6. A Condition 7 building shall be permitted to be classified as a Group B occupancy.

308.4.8 Condition 8. This occupancy condition shall include buildings containing not more than four secure interview rooms located within the same fire area where not more than six occupants under restraint are located in the same fire area. A Condition 8 building shall be is permitted to be classified as a Group B occupancy, provided the requirements in Section 408.1.2.7 are met.

308.4.9 Condition 9. This occupancy condition shall include buildings where the use of the building is for correctional medical care or correctional mental health care.

308.5 Institutional Group I-4, day care facilities. Institutional Group I-4 occupancy shall include buildings and structures occupied by more than six clients of any age who receive custodial care for fewer than 24 hours per day by persons other than parents or guardians; relatives by blood, marriage or adoption; and in a place other than the home of the clients cared for. This group shall include, but not be limited to, the following:

Adult day care

Child day care (not classified as Group E)
California Historical Building Code Medium relevance — show source text
(inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)|SINGLE-WALL METAL VENT CONNECTOR DIAMETER –****D (inch)| |||8|8|8|9|9|9|10|10|10| |||APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR|APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOUR| |VENT
HEIGHT
H
(feet)|CONNECTOR
RISE
R
(feet)|FAN|FAN|NAT|FAN|FAN|NAT|FAN|FAN|NAT| |VENT
HEIGHT
H
(feet)|CONNECTOR
RISE
R
(feet)**|Min|Max|Max|Min|Max|Max|Min|Max|Max| |6|1
2
3|262
271
279|293
331
361|183
219
247|325
334
344|373
422
462|234
281
316|447
458
468|463
524
574|286
344
385| |8|1
2
3|285
293
302|316
353
381|191
228
256|352
360
370|403
450
489|244
292
328|481
492
501|502
560
609|299
355
400| |10|1
2

CHBC § 2.1 Medium relevance — show source text

Exceptions:

Any stairway replacing an existing stairway within a space where the pitch or slope cannot be reduced shall not be required to comply with the maximum riser height and minimum tread depth requirements.
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.

1011.5.3 Egress capacity. Egress capacity shall meet or exceed the occupant load as specified in the California Building Code for the new occupancy.

1011.5.4 Handrails. Existing stairways shall comply with the handrail requirements of Section 804.13.

1011.5.5 Guards. Existing guards shall comply with the requirements in Section 804.12.

1011.5.6 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031 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.

10-6 2025 CALIFORNIA EXISTING BUILDING CODE

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

CHANGE OF OCCUPANCY

1011.6 Heights and areas. Hazard categories in regard to height and area shall be in accordance with Table 1011.6.

TABLE 1011.6—HEIGHTS AND AREAS HAZARD CATEGORIES	Col2
RELATIVE HAZARD	OCCUPANCY CLASSIFICATIONS
1 (Highest Hazard)	H
2	A-1; A-2; A-3; A-4; I; R-1; R-2; R-4, Condition 2
3	E; F-1; S-1; M
4 (Lowest Hazard)	B; F-2; S-2; A-5; R-3; R-4, Condition 1; U

1011.6.1 Height and area for change to a higher-hazard category. Where a change of occupancy classification is made to a higher-hazard category as shown in Table 1011.6, heights and areas of buildings and structures shall comply with the requirements of Chapter 5 of the California Building Code for the new occupancy classification.

Exceptions:

For high-rise buildings constructed in compliance with a previously issued permit, the type of construction reduction specified in Section 403.2.1 of the California Building Code is permitted. This shall include the reduction for columns.

Frequently asked questions

When does the CHBC treat a building as “qualified historical” for these relaxations?

The CHBC applies only to a qualified historical building or property as defined elsewhere in Chapter 8; the relaxations in §§ 8‑302.3–8‑302.5 apply only to those qualifying buildings. The specific qualification language is outside the quoted excerpts here; consult the CHBC definitions in Chapter 8‑2 for the full criteria.

If I add sprinklers only to parts of the building, do I get the CHBC relaxations?

Most CHBC relaxations require the building to be provided with an automatic sprinkler system throughout. Partial sprinkling typically will not trigger the full relaxations unless a specific provision (e.g., § 8‑302.5.1 for high‑rise scenarios) permits selective application with required fire barriers and alarm systems. §§ 8‑302.3, 8‑302.5.1.

Can I raise a historic building higher than it ever was if I meet fire‑protection conditions?

No. § 8‑302.5 allows height not to be limited because of construction type but still caps it at the building’s historical design. You may not exceed the historical height/number‑of‑stories under that section.

Are the CHBC floor‑area relaxations automatic when historic status is established?

No. The CHBC gives the allowance but the building owner must meet the conditions (e.g., full sprinklers or the residential alarm/exiting combination) and obtain approval from the enforcing agency. See § 8‑302.4.

If a required separation is reduced to 1 hour, what must the door assemblies be?

Openings must be protected by assemblies of not less than 3/4‑hour and doors with automatic‑closing devices must respond to products of combustion (not only to heat). § 8‑302.3.

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Related in the CHBC

When does the CHBC Fire Protection chapter apply to a qualified historical building?

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Scope & Fire‑resistive Construction

California Historical Building Code