CBC · California Building Code
How are fire‑resistance ratings determined and tested?
The CBC requires fire‑resistance ratings to be established primarily by standard tests (ASTM E119 or UL 263) performed without sprinklers, or by approved analytical or alternate methods; nonsymmetrical walls, added components, and exterior bearing walls have special test rules and the shorter test result controls when both faces are tested.
Last reviewed: July 5, 2026
What the code requires
The California Building Code requires that fire‑resistance ratings be established by standardized test procedures unless an approved analytical or alternate method is used. The default test procedures are ASTM E119 or UL 263; test ratings are determined without incorporating automatic sprinklers or other suppression systems unless specifically allowed by the alternate‑method provisions. See § 703.1 and § 703.2 for the scope and the required determination routes, and § 703.2.1 for the primary test standard requirement.
Requirements in detail
1) Three permitted ways to establish a rating
- Tested assemblies: A rating is to be determined by the fire‑endurance tests in ASTM E119 or UL 263 (the standard furnace/time‑temperature test) for building elements, components or assemblies. § 703.2.1.
- Analytical methods: The code permits specified analytical/design comparison methods (see § 703.2.2) as alternatives to testing (approved designs, prescriptive tables, calculations, engineering comparison, or certified designs). § 703.2.
- Approved alternate method: Where an assembly cannot be covered by the tested or analytical routes, the fire‑resistance may be established using an approved alternate protection method in accordance with § 104.2.3 and § 703.2.3. § 703.2.3.
2) Test standards and test conditions (key points)
- Standard tests: ASTM E119 or UL 263 are the baseline test standards for determining fire‑resistance ratings. § 703.2.1.
- No sprinklers in the standard rating: Ratings determined under § 703.2.1 and § 703.2 (tested or analytical) are to be determined without incorporating automatic sprinklers or other suppression systems unless an alternate method is used. § 703.2.
- Penetrations and joint systems: Penetrations and fire‑resistant joint systems have their own test and evaluation rules (see §§ 714 and 715 referenced by § 703.2.1). § 703.2.1.
3) Special testing rules (selected subsections of § 703.2.1)
- Nonsymmetrical walls: Interior walls of nonsymmetrical construction must be tested with both faces exposed; the assigned rating is the shorter of the two results unless the building official accepts evidence the least‑resistant side was already tested. § 703.2.1.1.
- Combustible components: Use of combustible aggregates or other components is permitted provided the finished tested assembly meets the code’s fire‑resistance test requirements. § 703.2.1.2.
- Restrained classification: Assemblies tested under ASTM E119/UL 263 are not assumed to be “restrained” for structural classification unless acceptable evidence from the registered design professional demonstrates qualification. § 703.2.1.3.
- Supplemental/un‑tested features: If materials or devices not tested as part of the assembly are added, sufficient data must be provided to the building official to show the rating is not reduced. § 703.2.1.4.
Decision‑relevant dimensions and values
| Decision item | Typical value / requirement | Code Reference |
|---|---|---|
| Primary test standards | ASTM E119 or UL 263 | § 703.2.1 |
| Determination without sprinklers (default) | No automatic sprinklers or suppression included in test assembly | § 703.2 |
| Nonsymmetrical wall testing | Test both faces; assign the shorter duration | § 703.2.1.1 |
| Alternate/approved method | Use § 104.2.3 procedure when not complying with tested/analytical methods | § 703.2.3 |
| Evidence for “restrained” classification | Registered design professional must furnish acceptable evidence | § 703.2.1.3 |
Exceptions & special cases
- Alternate protection: If an assembly cannot reasonably be tested or does not fit prescriptive/analytical sources, the designer may seek an approved alternate as permitted by § 703.2.3 (which relies on § 104.2.3 procedures for alternate methods). § 703.2.3.
- Exterior bearing walls: For exterior bearing walls there are specific adjustments to the ASTM E119/UL 263 acceptance criteria (temperature‑rise/ignition criteria and hose stream conditions may be modified based on comparable exterior nonbearing wall ratings and fire separation distance). See § 703.2.1.5.
- Added/unlisted components: If you add components not part of the tested assembly (for example, new face veneers, fasteners, services), you must supply data to the building official showing the rating is not degraded; you cannot assume the original test covers those changes. § 703.2.1.4.
Common mistakes
- Assuming a tested rating can include sprinkler protection by default — standard ratings under § 703.2.1 are determined without sprinklers unless an alternate method specifically permits it. § 703.2.
- Treating a single‑face test as sufficient for nonsymmetrical walls — unless the least‑resistant side is shown to have been the tested side and accepted by the building official, both faces must be tested and the shorter time controls. § 703.2.1.1.
- Adding untested components and assuming the original label still applies — the code requires data showing the rating is not reduced when supplemental features are introduced. § 703.2.1.4.
- Misclassifying restraint conditions for structural assemblies; “restrained” must be demonstrated with satisfactory evidence from a registered design professional. § 703.2.1.3.
Worked example
Scenario: A fire barrier is required to provide a 2‑hour (120‑minute) fire‑resistance rating. The designer has a tested wall assembly that achieved 120 minutes when tested per ASTM E119 with the “A” face exposed, but when the opposite face was tested (because the wall is nonsymmetrical) the wall only achieved 90 minutes.
Application of the code:
- Because the wall is nonsymmetrical, the test rule requires testing with both faces exposed and the assigned rating is the shorter duration obtained from the two tests, so the assigned rating becomes 90 minutes. § 703.2.1.1.
- To meet the code‑required 120‑minute rating the designer must either (a) use a different assembly that tests at 120 minutes on both faces; (b) provide acceptable analytical or approved alternate justification under § 703.2.2 or § 703.2.3 (with required evidence); or (c) modify the assembly (and retest) so both faces achieve 120 minutes. § 703.2, § 703.2.1, § 703.2.3.
Related provisions
- Scope and general application: § 703.1.
- Fire‑resistance determination methods (overview): § 703.2.
- Test procedures (ASTM E119 / UL 263 requirement and related subsections): § 703.2.1.
- Approved alternate method for unusual cases: § 703.2.3.
- Noncombustibility test criteria (related material tests): § 703.3.
Code references
Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:
CBC § 703.1 High relevance — show source text
SECTION 703—FIRE-RESISTANCE RATINGS AND FIRE TESTS
703.1 Scope. Materials prescribed herein for fire resistance shall conform to the requirements of this chapter.
703.2 Fire resistance. The fire-resistance rating of building elements, components or assemblies shall be determined in accordance with Section 703.2.1 or 703.2.2 without the use of automatic sprinklers or any other fire suppression system being incorporated, or in accordance with Section 703.2.3.
703.2.1 Tested assemblies. A fire-resistance rating of building elements, components or assemblies shall be determined by the test procedures set forth in ASTM E119 or UL 263. The fire-resistance rating of penetrations and fire-resistant joint systems shall be determined in accordance with Sections 714 and 715, respectively.
703.2.1.1 Nonsymmetrical wall construction. Interior walls and partitions of nonsymmetrical construction shall be tested with both faces exposed to the furnace, and the assigned fire-resistance rating shall be the shortest duration obtained from the two tests conducted in compliance with ASTM E119 or UL 263. Where evidence is furnished to show that the wall was tested with the least fire-resistant side exposed to the furnace, subject to acceptance of the building official, the wall need not be subjected to tests from the opposite side (see Section 705.5 for exterior walls).
703.2.1.2 Combustible components. Combustible aggregates are permitted in gypsum and Portland cement concrete mixtures for fire-resistance-rated construction. Any component material or admixture is permitted in assemblies if the resulting tested assembly meets the fire-resistance test requirements of this code.
703.2.1.3 Restrained classification. Fire-resistance-rated assemblies tested under ASTM E119 or UL 263 shall not be considered to be restrained unless evidence satisfactory to the building official is furnished by the registered design professional showing that the construction qualifies for a restrained classification in accordance with ASTM E119 or UL 263. Restrained construction shall be identified on the construction documents.
703.2.1.4 Supplemental features. Where materials, systems or devices that have not been tested as part of a fire-resistancerated assembly are incorporated into the building element, component or assembly, sufficient data shall be made available to the building official to show that the required fire-resistance rating is not reduced.
703.2.1.5 Exterior bearing walls. In determining the fire-resistance rating of exterior bearing walls, compliance with the ASTM E119 or UL 263 criteria for unexposed surface temperature rise and ignition of cotton waste due to passage of flame or gases is required only for a period of time corresponding to the required fire-resistance rating of an exterior nonbearing wall with the same fire separation distance, and in a building of the same group. Where the fire-resistance rating determined in accordance with this exception exceeds the fire-resistance rating determined in accordance with ASTM E119 or UL 263, the fire exposure time period, water pressure and application duration criteria for the hose stream test of ASTM E119 or UL 263 shall be based on the fire-resistance rating determined in accordance with this section.
703.2.2 Analytical methods. The fire resistance of building elements, components or assemblies established by an analytical method shall be by any of the methods listed in this section, based on the fire exposure and acceptance criteria specified in ASTM E119 or UL 263.
- Fire-resistance designs documented in approved sources.
- Prescriptive designs of fire-resistance-rated building elements, components or assemblies as prescribed in Section 721.
CBC § 2.1 High relevance — show source text
2.1_||||X|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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7 FIRE AND SMOKE PROTECTION FEATURES
User notes:
About this chapter: Chapter 7 provides detailed requirements for fire-resistance-rated construction, including structural members, walls, partitions and horizontal assemblies. Other portions of the code describe where certain fire-resistance-rated elements are required. This chapter specifies how these elements are constructed, how openings in walls and partitions are protected and how penetrations of such elements are protected.
SECTION 701—GENERAL
701.1 Scope. The provisions of this chapter shall govern the materials, systems and assemblies used for structural fire resistance and fire-resistance-rated construction separation of adjacent spaces to safeguard against the spread of fire and smoke within a building and the spread of fire to or from buildings.
SECTION 702—MULTIPLE-USE FIRE ASSEMBLIES
702.1 Multiple-use fire assemblies. Fire assemblies that serve multiple purposes in a building shall comply with all of the requirements that are applicable for each of the individual fire assemblies.
SECTION 703—FIRE-RESISTANCE RATINGS AND FIRE TESTS
703.1 Scope. Materials prescribed herein for fire resistance shall conform to the requirements of this chapter.
703.2 Fire resistance. The fire-resistance rating of building elements, components or assemblies shall be determined in accordance with Section 703.2.1 or 703.2.2 without the use of automatic sprinklers or any other fire suppression system being incorporated, or in accordance with Section 703.2.3.
703.2.1 Tested assemblies. A fire-resistance rating of building elements, components or assemblies shall be determined by the test procedures set forth in ASTM E119 or UL 263. The fire-resistance rating of penetrations and fire-resistant joint systems shall be determined in accordance with Sections 714 and 715, respectively.
703.2.1.1 Nonsymmetrical wall construction. Interior walls and partitions of nonsymmetrical construction shall be tested with both faces exposed to the furnace, and the assigned fire-resistance rating shall be the shortest duration obtained from the two tests conducted in compliance with ASTM E119 or UL 263. Where evidence is furnished to show that the wall was tested with the least fire-resistant side exposed to the furnace, subject to acceptance of the building official, the wall need not be subjected to tests from the opposite side (see Section 705.5 for exterior walls).
703.2.1.2 Combustible components. Combustible aggregates are permitted in gypsum and Portland cement concrete mixtures for fire-resistance-rated construction. Any component material or admixture is permitted in assemblies if the resulting tested assembly meets the fire-resistance test requirements of this code.
CBC § 716.1.2.3 High relevance — show source text
Fire-resistance-rated
glazing assemblies tested to ASTM E119 or UL 263, as specified in Section 716.1.2.3, shall be permitted.|NP = Not Permitted.
a. Not permitted except fire-resistance-rated glazing assemblies tested to ASTM E119 or UL 263, as specified in Section 716.1.2.3.
b. XXX = The fire rating duration period in minutes, which shall be equal to the fire-resistance rating required for the wall assembly.
c. Fire-protection-rated glazing is not permitted for fire barriers required by Section 1207 of the_California Fire Code_ to enclose energy storage systems. Fire-resistance-rated
glazing assemblies tested to ASTM E119 or UL 263, as specified in Section 716.1.2.3, shall be permitted.|NP = Not Permitted.
a. Not permitted except fire-resistance-rated glazing assemblies tested to ASTM E119 or UL 263, as specified in Section 716.1.2.3.
b. XXX = The fire rating duration period in minutes, which shall be equal to the fire-resistance rating required for the wall assembly.
c. Fire-protection-rated glazing is not permitted for fire barriers required by Section 1207 of the_California Fire Code_ to enclose energy storage systems. Fire-resistance-rated
glazing assemblies tested to ASTM E119 or UL 263, as specified in Section 716.1.2.3, shall be permitted.|2025 CALIFORNIA BUILDING CODE 7-29
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FIRE AND SMOKE PROTECTION FEATURES
716.1.1 Alternative methods for determining fire protection ratings. The application of any of the alternative methods specified in this section shall be based on the fire exposure and acceptance criteria specified in NFPA 252, NFPA 257, UL 9, UL 10B or UL 10C. The required fire protection rating of an opening protective shall be permitted to be established by any of the following methods or procedures:
- Designs documented in approved sources.
- Engineering analysis based on a comparison of opening protective designs having fire protection ratings as determined by the test procedures set forth in NFPA 252, NFPA 257, UL 9, UL 10B or UL 10C.
- Alternative protection methods as allowed by Section 104.2.3.
716.1.2 Glazing. Glazing used in fire door assemblies and fire window assemblies shall comply with this section in addition to the requirements of Sections 716.2 and 716.3, respectively.
716.1.2.1 Safety glazing. Fire-protection-rated glazing and fire-resistance-rated glazing installed in fire door assemblies and fire window assemblies shall comply with the safety glazing requirements of Chapter 24 where applicable.
716.1.2.2 Marking fire-rated glazing assemblies. Fire-rated glazing assemblies shall be marked in accordance with Tables 716.1(1), 716.1(2) and 716.1(3).
CBC § 7-3 High relevance — show source text
Calculations in accordance with Section 722.
Engineering analysis based on a comparison of building element, component or assemblies designs having fire-resistance ratings as determined by the test procedures set forth in ASTM E119 or UL 263.
Fire-resistance designs certified by an approved agency.
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FIRE AND SMOKE PROTECTION FEATURES
703.2.3 Approved alternate method. The fire resistance of building elements, components or assemblies not complying with Section 703.2.1 or 703.2.2 shall be permitted to be established by an alternative protection method in accordance with Section 104.2.3.
703.3 Noncombustibility tests. The tests indicated in Section 703.3.1 shall serve as criteria for acceptance of building materials as set forth in Sections 602.2, 602.3 and 602.4 in Types I, II, III and IV construction. The term “noncombustible” does not apply to the flame spread characteristics of interior finish or trim materials. A material shall not be classified as a noncombustible building construction material if it is subject to an increase in combustibility or flame spread beyond the limitations herein established through the effects of age, moisture or other atmospheric conditions.
703.3.1 Noncombustible materials. Materials required to be noncombustible shall be tested in accordance with ASTM E136. Alternately, materials required to be noncombustible shall be tested in accordance with ASTM E2652 using the acceptance criteria prescribed by ASTM E136.
Exception: Materials having a structural base of noncombustible material as determined in accordance with ASTM E136, or with ASTM E2652 using the acceptance criteria prescribed by ASTM E136, with a surfacing of not more than 0.125 inch (3.18 mm) in thickness having a flame spread index not greater than 50 when tested in accordance with ASTM E84 or UL 723 shall be acceptable as noncombustible.
703.4 Fire-resistance-rated glazing. Fire-resistance-rated glazing, when tested in accordance with ASTM E119 or UL 263 and complying with the requirements of Section 707, shall be permitted. Fire-resistance-rated glazing shall bear a label marked in accordance with Table 716.1(1) issued by an agency and shall be permanently identified on the glazing.
703.5 Marking and identification. Where there is an accessible concealed floor, floor-ceiling or attic space, fire walls, fire barriers, fire partitions, smoke barriers and smoke partitions or any other wall required to have protected openings or penetrations shall be effectively and permanently identified with signs or stenciling in the concealed space. Such identification shall:
- Be located within 15 feet (4572 mm) of the end of each wall and at intervals not exceeding 30 feet (9144 mm) measured horizontally along the wall or partition.
- Include lettering not less than 3 inches (76 mm) in height with a minimum [3] / 8 -inch (9.5 mm) stroke in a contrasting color incorporating the suggested wording, “FIRE AND/OR SMOKE BARRIER—PROTECT ALL OPENINGS,” or other wording.
**703.6 Determination of noncombustible protection time contribution.
CBC § 25.4 High relevance — show source text
The fire-resistance rating for this thickness exceeds 4 hours.|For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.02 kg/m3.
a. Dry unit weight of 35 pcf or less and consisting of cellular, perlite or_vermiculite_ concrete.
b. The_R n_ 0.59 value for one1/2″ to 31/2″ airspace is 3.3. The_Rn_
0.59 value for two1/2″ to 31/2″ airspaces is 6.7.
c. The fire-resistance rating for this thickness exceeds 4 hours.|For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.02 kg/m3.
a. Dry unit weight of 35 pcf or less and consisting of cellular, perlite or_vermiculite_ concrete.
b. The_R n_ 0.59 value for one1/2″ to 31/2″ airspace is 3.3. The_Rn_
0.59 value for two1/2″ to 31/2″ airspaces is 6.7.
c. The fire-resistance rating for this thickness exceeds 4 hours.|For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.02 kg/m3.
a. Dry unit weight of 35 pcf or less and consisting of cellular, perlite or_vermiculite_ concrete.
b. The_R n_ 0.59 value for one1/2″ to 31/2″ airspace is 3.3. The_Rn_
0.59 value for two1/2″ to 31/2″ airspaces is 6.7.
c. The fire-resistance rating for this thickness exceeds 4 hours.|TABLE 722.2.1.2(2)—FIRE-RESISTANCE RATINGS BASED ON R0.59 Col2 Ra, MINUTES R0.59 60 11.20 120 16.85 180 21.41 240 25.37 a. Based on Equation 7-4. a. Based on Equation 7-4. For SI: 1 inch = 25.4 mm.
722.2.1.2.1 Two or more wythes. The fire-resistance rating for wall panels consisting of two or more wythes shall be permitted to be determined by the formula: Equation 7-4 R = ( R 10.59 + R 20.59 +...+ R n 0.59 ) 1.7
where:
R = The fire endurance of the assembly, minutes. R 1 , R 2 , and R n = The fire endurances of the individual wythes, minutes. Values of R n0.59 for use in Equation 7-4 are given in Table 722.2.1.2(1). Calculated fire-resistance ratings are shown in Table 722.2.1.2(2).
CBC § 703.7 High relevance — show source text
The test assemblies shall be identical in construction, loading and materials, other than the noncombustible protection. The two test assemblies shall be tested to the same criteria of structural failure with the following conditions:
- Test Assembly 1 shall be without protection.
- Test Assembly 2 shall include the representative noncombustible protection. The protection shall be fully defined in terms of configuration details, attachment details, joint sealing details, accessories and all other relevant details.
The noncombustible protection time contribution shall be determined by subtracting the fire-resistance time, in minutes, of Test Assembly 1 from the fire-resistance time, in minutes, of Test Assembly 2.
703.7 Sealing of adjacent mass timber elements. In buildings of Types IV-A, IV-B and IV-C construction, sealant or adhesive shall be provided to resist the passage of air in the following locations:
- At abutting edges and intersections of mass timber building elements required to be fire-resistance rated.
- At abutting intersections of mass timber building elements and building elements of other materials where both are required to be fire-resistance rated.
Sealants shall meet the requirements of ASTM C920. Adhesives shall meet the requirements of ASTM D3498.
Exception: Sealants or adhesives need not be provided where they are not a required component of a tested fire-resistance-rated assembly.
SECTION 704—FIRE-RESISTANCE RATING OF STRUCTURAL MEMBERS
704.1 Requirements. The fire-resistance ratings of structural members and assemblies shall comply with this section and the requirements for the type of construction as specified in Table 601.
704.1.1 Supporting construction. The fire-resistance ratings of supporting structural members and assemblies shall be not less than the ratings required for the fire-resistance-rated assemblies supported by the structural members.
Exception: Structural members and assemblies that support fire barriers, fire partitions, smoke barriers and horizontal assemblies as provided in Sections 707.5, 708.4, 709.4 and 711.2, respectively.
704.2 Protection of the primary structural frame. Members of the primary structural frame that are required to have protection to achieve a fire-resistance rating shall be provided individual encasement protection by protecting them on all sides for the full length, including connections to other structural members, with materials having the required fire-resistance rating. Where a column extends through a ceiling, the encasement protection shall be continuous from the top of the foundation or floor/ceiling assembly below through the ceiling space to the top of the column.
Exceptions:
- Individual encasement protection on all sides shall be permitted on all exposed sides provided that the extent of protection is in accordance with the required fire-resistance rating, as determined in Section 703.
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FIRE AND SMOKE PROTECTION FEATURES
Primary structural members other than columns that do not support more than two floors or one floor and roof, or a load-bearing wall or a nonload-bearing wall more than two stories high, are permitted to be protected by the membrane of a fire-resistance-rated wall or horizontal assembly where the membrane provides the required fire-resistance rating.
Columns that meet the limitations of Section 704.3.1.
CBC § 703.2.1.4 High relevance — show source text
703.2.1.4 Supplemental features. Where materials, systems or devices that have not been tested as part of a fire-resistancerated assembly are incorporated into the building element, component or assembly, sufficient data shall be made available to the building official to show that the required fire-resistance rating is not reduced.
703.2.1.5 Exterior bearing walls. In determining the fire-resistance rating of exterior bearing walls, compliance with the ASTM E119 or UL 263 criteria for unexposed surface temperature rise and ignition of cotton waste due to passage of flame or gases is required only for a period of time corresponding to the required fire-resistance rating of an exterior nonbearing wall with the same fire separation distance, and in a building of the same group. Where the fire-resistance rating determined in accordance with this exception exceeds the fire-resistance rating determined in accordance with ASTM E119 or UL 263, the fire exposure time period, water pressure and application duration criteria for the hose stream test of ASTM E119 or UL 263 shall be based on the fire-resistance rating determined in accordance with this section.
703.2.2 Analytical methods. The fire resistance of building elements, components or assemblies established by an analytical method shall be by any of the methods listed in this section, based on the fire exposure and acceptance criteria specified in ASTM E119 or UL 263.
Fire-resistance designs documented in approved sources.
Prescriptive designs of fire-resistance-rated building elements, components or assemblies as prescribed in Section 721.
Calculations in accordance with Section 722.
Engineering analysis based on a comparison of building element, component or assemblies designs having fire-resistance ratings as determined by the test procedures set forth in ASTM E119 or UL 263.
Fire-resistance designs certified by an approved agency.
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FIRE AND SMOKE PROTECTION FEATURES
703.2.3 Approved alternate method. The fire resistance of building elements, components or assemblies not complying with Section 703.2.1 or 703.2.2 shall be permitted to be established by an alternative protection method in accordance with Section 104.2.3.
703.3 Noncombustibility tests. The tests indicated in Section 703.3.1 shall serve as criteria for acceptance of building materials as set forth in Sections 602.2, 602.3 and 602.4 in Types I, II, III and IV construction. The term “noncombustible” does not apply to the flame spread characteristics of interior finish or trim materials. A material shall not be classified as a noncombustible building construction material if it is subject to an increase in combustibility or flame spread beyond the limitations herein established through the effects of age, moisture or other atmospheric conditions.
703.3.1 Noncombustible materials. Materials required to be noncombustible shall be tested in accordance with ASTM E136. Alternately, materials required to be noncombustible shall be tested in accordance with ASTM E2652 using the acceptance criteria prescribed by ASTM E136.
CBC § 25.4 High relevance — show source text
This table applies only to wood joist construction. It is not applicable to wood truss construction.|For SI: 1 inch = 25.4 mm.
a. This table applies only to wood joist construction. It is not applicable to wood truss construction.|For SI: 1 inch = 25.4 mm.
a. This table applies only to wood joist construction. It is not applicable to wood truss construction.|TABLE 722.6.2(5)—TIME ASSIGNED FOR ADDITIONAL PROTECTION Col2 DESCRIPTION OF ADDITIONAL PROTECTION FIRE RESISTANCE
(minutes)Add to the fire-resistance rating of wood stud walls if the spaces between the studs are completely filled with glass
fiber mineral wool batts weighing not less than 2 pounds per cubic foot (0.6 pound per square foot of wall surface),
or cellulose insulation having a nominal density not less than 2.6 pounds per cubic foot.15 For SI: 1 pound/cubic foot = 16.0185 kg/m3. For SI: 1 pound/cubic foot = 16.0185 kg/m3. 722.6.2.1 Fire-resistance rating of wood frame assemblies. The fire-resistance rating of a wood frame assembly is equal to the sum of the time assigned to the membrane on the fire-exposed side, the time assigned to the framing members and the time assigned for additional contribution by other protective measures such as insulation. The membrane on the unexposed side shall not be included in determining the fire resistance of the assembly.
722.6.2.2 Time assigned to membranes. Table 722.6.2(1) indicates the time assigned to membranes on the fire-exposed side.
722.6.2.3 Exterior walls. For an exterior wall with a fire separation distance greater than 10 feet (3048 mm), the wall is assigned a rating dependent on the interior membrane and the framing as described in Table 722.6.2(1) and Table 722.6.2(2). The membrane on the outside of the nonfire-exposed side of exterior walls with a fire separation distance greater than 10 feet (3048 mm) shall consist of sheathing, sheathing paper and siding as described in Table 722.6.2(3).
722.6.2.4 Floors and roofs. In the case of a floor or roof, the standard test provides only for testing for fire exposure from below. Except as noted in Section 703.2.3, floor or roof assemblies of wood framing shall have an upper membrane consisting of a subfloor and finished floor conforming to Table 722.6.2(4) or any other membrane that has a contribution to fire resistance of not less than 15 minutes in Table 722.6.2(1).
722.6.2.5 Additional protection. Table 722.6.2(5) indicates the time increments to be added to the fire resistance where glass fiber, rockwool, slag mineral wool or cellulose insulation is incorporated in the assembly.
722.6.2.6 Fastening. Fastening of wood frame assemblies and the fastening of membranes to the wood framing members shall be done in accordance with Chapter 23.
722.7 Fire-resistance rating for mass timber. The required fire resistance of mass timber elements in Section 602.4 shall be determined in accordance with Section 703.2 or Section 703.3 . The fire-resistance rating of building elements shall be as required in Tables
CBC § 722.6.2 High relevance — show source text
Any combination of sheathing, paper and exterior finish is permitted.|
TABLE 722.6.2(4)—FLOORING OR ROOFING OVER WOOD FRAMINGa Col2 Col3 Col4 ASSEMBLY STRUCTURAL MEMBERS SUBFLOOR OR ROOF DECK FINISHED FLOORING OR ROOFING Floor Wood 15/32-inch wood structural panels
or11/16-inch T & G softwoodHardwood or softwood flooring on building paper; resil-
ient flooring; parquet floor; felted-synthetic fiber floor
coverings, carpeting, or ceramic tile on1/4-inch-thick
fiber-cement underlayment or3/8-inch-thick panel-type
underlayment; ceramic tile on 11/4-inch mortar bed.Roof Wood 15/32-inch wood structural panels
or11/16-inch T & G softwoodFinished roofing material with or without insulation For SI: 1 inch = 25.4 mm.
a. This table applies only to wood joist construction. It is not applicable to wood truss construction.For SI: 1 inch = 25.4 mm.
a. This table applies only to wood joist construction. It is not applicable to wood truss construction.For SI: 1 inch = 25.4 mm.
a. This table applies only to wood joist construction. It is not applicable to wood truss construction.For SI: 1 inch = 25.4 mm.
a. This table applies only to wood joist construction. It is not applicable to wood truss construction.TABLE 722.6.2(5)—TIME ASSIGNED FOR ADDITIONAL PROTECTION Col2 DESCRIPTION OF ADDITIONAL PROTECTION FIRE RESISTANCE
(minutes)Add to the fire-resistance rating of wood stud walls if the spaces between the studs are completely filled with glass
fiber mineral wool batts weighing not less than 2 pounds per cubic foot (0.6 pound per square foot of wall surface),
or cellulose insulation having a nominal density not less than 2.6 pounds per cubic foot.15 For SI: 1 pound/cubic foot = 16.0185 kg/m3. For SI: 1 pound/cubic foot = 16.0185 kg/m3. 722.6.2.1 Fire-resistance rating of wood frame assemblies. The fire-resistance rating of a wood frame assembly is equal to the sum of the time assigned to the membrane on the fire-exposed side, the time assigned to the framing members and the time assigned for additional contribution by other protective measures such as insulation. The membrane on the unexposed side shall not be included in determining the fire resistance of the assembly.
722.6.2.2 Time assigned to membranes. Table 722.6.2(1) indicates the time assigned to membranes on the fire-exposed side.
CBC § 704.5.1 High relevance — show source text
704.5.1 Secondary attachments to structural members. Where primary and secondary structural steel members require fire protection, any additional structural steel members having direct connection to the primary structural frame or secondary structural members shall be protected with the same fire-resistive material and thickness as required for the structural member. The protection shall extend away from the structural member a distance of not less than 12 inches (305 mm), or shall be applied to the entire length where the attachment is less than 12 inches (305 mm) long. Where an attachment is hollow and the ends are open, the fire-resistive material and thickness shall be applied to both exterior and interior of the hollow steel attachment.
704.6 Reinforcing. Thickness of protection for concrete or masonry reinforcement shall be measured to the outside of the reinforcement except that stirrups and spiral reinforcement ties are permitted to project not more than 0.5 inch (12.7 mm) into the protection.
704.7 Embedments and enclosures. Pipes, wires, conduits, ducts or other service facilities shall not be embedded in the required fire protective covering of a structural member that is required to be individually encased.
704.8 Impact protection. Where the fire protective covering of a structural member is subject to impact damage from moving vehicles, the handling of merchandise or other activity, the fire protective covering shall be protected by corner guards or by a substantial jacket of metal or other noncombustible material to a height adequate to provide full protection, but not less than 5 feet (1524 mm) from the finished floor.
Exception: Corner protection is not required on concrete columns in parking garages.
704.9 Exterior structural members. Load-bearing structural members located within the exterior walls or on the outside of a building or structure shall be provided with the highest fire-resistance rating as determined in accordance with the following:
- As required by Table 601 for the type of building element based on the type of construction of the building.
- As required by Table 601 for exterior bearing walls based on the type of construction.
- As required by Table 705.5 for exterior walls based on the fire separation distance.
704.10 Bottom flange protection. Fire protection is not required at the bottom flange of lintels, shelf angles and plates, spanning not more than 6 feet 4 inches (1931 mm) whether part of the primary structural frame or not, and from the bottom flange of lintels, shelf angles and plates not part of the structural frame, regardless of span.
704.11 Seismic isolation systems. Fire-resistance ratings for the isolation system shall meet the fire-resistance rating required for the columns, walls or other structural elements in which the isolation system is installed in accordance with Table 601. Isolation systems required to have a fire-resistance rating shall be protected with approved materials or construction assemblies designed to provide the same degree of fire resistance as the structural element in which the system is installed when tested in accordance with ASTM E119 or UL 263 (see Section 703.2).
Such isolation system protection applied to isolator units shall be capable of retarding the transfer of heat to the isolator unit in such a manner that the required gravity load-carrying capacity of the isolator unit will not be impaired after exposure to the standard time-temperature curve fire test prescribed in ASTM E119 or UL 263 for a duration not less than that required for the fire-resistance rating of the structure element in which the system is installed.
CBC § 722.2.1.2.2 Medium relevance — show source text
722.2.1.2.2 Foam plastic insulation. The fire-resistance ratings of precast concrete wall panels consisting of a layer of foam plastic insulation sandwiched between two wythes of concrete shall be permitted to be determined by use of Equation 7-4. Foam plastic insulation with a total thickness of less than 1 inch (25 mm) shall be disregarded. The R n value for thickness of foam plastic insulation of 1 inch (25 mm) or greater, for use in the calculation, is 5 minutes; therefore R n0.59 = 2.5.
2025 CALIFORNIA BUILDING CODE 7-67
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
FIRE AND SMOKE PROTECTION FEATURES
722.2.1.3 Joints between precast wall panels. Joints between precast concrete wall panels that are not insulated as required by this section shall be considered as openings in walls. Uninsulated joints shall be included in determining the percentage of openings permitted by Table 705.9. Where openings are not permitted or are required by this code to be protected, the provisions of this section shall be used to determine the amount of joint insulation required. Insulated joints shall not be considered openings for purposes of determining compliance with the allowable percentage of openings in Table 705.9.
722.2.1.3.1 Ceramic fiber joint protection. Figure 722.2.1.3.1 shows thicknesses of ceramic fiber blankets to be used to insulate joints between precast concrete wall panels for various panel thicknesses and for joint widths of [3] / 8 inch (9.5 mm) and 1 inch (25 mm) for fire-resistance ratings of 1 hour to 4 hours. For joint widths between [3] / 8 inch (9.5 mm) and 1 inch (25 mm), the thickness of ceramic fiber blanket is allowed to be determined by direct interpolation. Other tested and labeled materials are acceptable in place of ceramic fiber blankets.
FIGURE 722.2.1.3.1—CERAMIC FIBER JOINT PROTECTION
For SI: 1 inch = 25.4 mm.
722.2.1.4 Concrete walls with gypsum wallboard or plaster finishes. The fire-resistance rating of cast-in-place or precast concrete walls with finishes of gypsum wallboard or plaster applied to one or both sides shall be permitted to be calculated in accordance with the provisions of this section
|TABLE 722.2.1.
CBC § 504.3 Medium relevance — show source text
504.3 Protection of enclosed eaves. The exposed underside of enclosed roof eaves and soffits shall be protected on the exposed underside by one or more of the following:
1. Noncombustible materials.
2. Ignition-resistant building materials. 3. Materials approved for not less than 1-hour fire-resistance-rated construction on the exterior side, as tested in accordance with ASTM E119 or UL 263.
4. 2-inch (51 mm) nominal dimension lumber . 5. 1-inch (25 mm) nominal fire-retardant-treated lumber or [3] / 4 -inch (19.1 mm) nominal fire-retardant-treated plywood, identified for exterior use and complying with Section 2303.2 of the California Building Code . 6. Boxed-in roof eave soffit assemblies with an underside that meets the performance criteria in Section 504.7.2 when tested in accordance with the test procedures set forth in ASTM E2957. 7. Boxed-in roof eave soffit assemblies with an underside that meets the performance criteria in accordance with the test proce- dures set forth in SFM Standard 12-7A-3.
Facias are required and shall be ignition-resistant building materials , fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code, materials approved for not less than 1-hour fire-resistance-rated construction or 2-inch (51 mm) nominal dimension lumber.
504.3.1 Protection of open eaves. The exposed roof deck on the underside of unenclosed roof eaves shall consist of one or more of the following:
1. Noncombustible material.
2. Ignition-resistant building material. 3. Fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code. 4. Materials approved for not less than 1-hour fire-resistance-rated construction on the exterior side, as tested in accordance with ASTM E119 or UL 263.
5. 2-inch (51 mm) nominal dimension lumber. 6. One layer of [5] / 8 -inch (16 mm) Type X gypsum sheathing applied behind an exterior covering on the underside of the roof deck.
7. The exterior portion of a 1-hour fire-resistance-rated exterior assembly, as tested in accordance with ASTM E119 or UL 263, applied to the underside of the roof deck designed for exterior fire exposure, including assemblies using the gypsum panel and sheathing products listed in the Gypsum Association Fire Resistance Design Manual.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 5-5
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
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SPECIAL BUILDING CONSTRUCTION REGULATIONS
Facias, if provided, shall be of fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the Cali- fornia Building Code, ignition-resistant building materials, materials approved for not less than 1-hour fire-resistance-rated construction or 2-inch (51 mm) nominal dimension lumber.
Frequently asked questions
What standard tests does the CBC require for fire‑resistance ratings?
The CBC requires ASTM E119 or UL 263 as the standard furnace/time‑temperature tests for determining fire‑resistance ratings unless an analytical or approved alternate method is used. § 703.2.1.
Can a sprinkler system be included in a tested assembly to obtain a higher rating?
No — ratings established under the standard tested or analytical methods are determined without the use of automatic sprinklers or other suppression systems unless an approved alternate method permits otherwise. § 703.2.
If I add a decorative veneer to a tested fire‑rated wall, does the label still apply?
Not automatically. If materials or devices not part of the tested assembly are added, the designer must provide sufficient data to the building official showing the required fire‑resistance rating is not reduced. § 703.2.1.4.
For a nonsymmetrical interior wall, which test result controls?
Both faces must be tested and the assigned rating is the shorter of the two durations obtained, unless the building official accepts proof that the least‑resistant side was already tested. § 703.2.1.1.
What if an assembly can't be tested or found in approved sources?
You may pursue an approved alternate protection method per § 104.2.3 as allowed by § 703.2.3; this requires submission and approval of the alternate methodology. § 703.2.3.
More in California Building Code
- Administration & Permits
- Energy Efficiency
- Existing Buildings
- Occupancy Classification & Use
- Hazardous Materials & Occupancies
- Types of Construction
- Fire-Resistance & Fire Safety
- Interior Finishes
- Means of Egress
- Accessibility
- Exterior Walls
- Roofing & Roof Assemblies
- Structural Design
- Special Inspections & Tests
- Foundations & Soils
- Concrete
- Masonry
- Steel
- Wood
- Elevators & Conveying Systems
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