CBC · California Building Code

Prescriptive vs calculated fire‑resistance methods (Tables and Section 721/722)

The CBC lets you either use prescriptive table entries in § 721 (quick, table‑based assumed ratings) or perform the calculation procedures in § 722 (tailored engineering methods using specified standards). If you alter a listed assembly you must show by test/data that the rating isn’t reduced; if you calculate, follow the exact standards and tables cited in § 722.

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

The California Building Code gives two permitted, mutually compatible ways to establish a fire‑resistance rating for elements: (1) use the prescriptive constructions and assumed ratings in Section 721 (the prescriptive tables), or (2) establish ratings by calculation using the procedures in Section 722. See § 721.1 for the prescriptive approach and § 722.1 for the allowed calculation procedures; either approach must show the required rating without relying on sprinklers unless otherwise permitted by other sections.

Requirements in detail

Core rule (short)

Prescriptive method: use the materials, thicknesses and assemblies listed in the tables in Section 721. The tables in § 721.1 list construction details that "shall be assumed to have the fire‑resistance ratings prescribed therein."
Calculated method: use the calculation procedures contained in Section 722; the calculation rules in § 722.1 limit which calculation references are permitted (ACI 216.1/TMS 0216 for concrete, PCI for precast, ASCE for steel, ANSI/AWC NDS for exposed wood, etc.).

When to use each method

Use the prescriptive tables when you can match your element/assembly to one of the table entries in Section 721; the tables provide assumed ratings without test reports.
Use Section 722 when your element/assembly is not covered by the prescriptive tables or you want a design‑specific solution (for example when using alternate materials, unusual cross‑sections, or multi‑wythe masonry). § 722.1 enumerates the acceptable calculation standards and scopes.

Key constraints and documentation

If you rely on a prescriptive table entry but alter the assembly in a way that changes heat‑dissipation or other performance, you must provide test results or other substantiating data to the building official to show the rating is not reduced (see § 721.1).
Calculated ratings are only permitted by the methods explicitly listed in § 722.1; you cannot invent an alternate general calculation method unless it is accepted via approval process (e.g., Section 104 alternatives).

Decision‑relevant summary table

Decision factor	Prescriptive (Section 721)	Calculated (Section 722)	Code Reference
Use when	Assembly exactly fits a table entry	Assembly not in tables or designer needs a tailored calculation	§ 721.1; § 722.1
Source of rating	Table assumed ratings (no test submittal if unmodified)	Calculation per referenced standards (ACI, PCI, ASCE, NDS)	§ 721.1; § 722.1
Typical governed materials	Insulation thicknesses, protected steel, specified concrete/masonry assemblies	Concrete, CMU, clay masonry, steel, exposed wood — using specified engineering methods	Tables 721.1(1)–(3); § 722.2–722.6
Documentation required	Reference table entry on drawings; if modified, test data or substantiation	Full calculation package using the listed standards; show equations/tables used	§ 721.1; § 722.1
When not allowed	If assembly uses unlisted test‑only features without substantiation	If calculation method is not one of the allowed references in § 722.1	§ 721.1; § 722.1

Representative prescriptive values (how the tables are used)

Section 721.1 contains TABULAR minimum protections (for example Table 721.1(1) lists minimum insulating thicknesses for steel columns/primary trusses to achieve 1–4 hour ratings). Use the exact table row that matches your material and member size — the table entries are treated by the code as the assumed rating for that construction. Do not substitute a different insulating material or thickness without demonstrating equivalence.

Representative calculation references (how Section 722 is organized)

Section 722.1 restricts the calculation paths: concrete/CMU/clay masonry per ACI 216.1/TMS 0216, precast per PCI 124, steel per ASCE (Chapter 5 of ASCE 29), and exposed wood per ANSI/AWC NDS Chapter 16. The detailed subsections (§§ 722.2–722.6) provide specific formulas, equivalent‑thickness tables, W/D (weight/diameter or width/thickness) tables for steel, and other numeric tables used in the calculation procedures.

Exceptions & special cases

Substitutions or component changes that affect heat dissipation: even if an assembly matches a 721 table entry, adding materials that change the heat‑flow (e.g., lightweight insulating facings, adhesives, dense claddings) require test evidence or substantiation to the building official showing the rating is not reduced (see § 721.1).
Scope limit of calculation rules: § 722.1 explicitly states the calculation procedures apply only to the information contained in Section 722 and must be executed using the listed references; do not use § 722 procedures for other, unrelated analyses.
Multi‑wythe and composite walls: § 722 contains specific rules for multi‑wythe masonry and how to derive an equivalent thickness or combined rating (see the multi‑wythe provisions and the tables under § 722.4). If using multi‑wythe calculation tables, follow the code equations for equivalent thickness exactly.

Common mistakes

Mixing methods without documentation: citing a prescriptive table entry but providing a calculated thickness without referencing the allowed § 722 standard or without demonstrating equivalence. The code treats the two approaches differently; you must document which approach you used and why.
Forgetting the "no‑sprinkler" baseline: fire‑resistance ratings in Chapter 7 are determined without assuming automatic sprinklers unless a specific section modifies that baseline; be explicit when sprinkler credit is used. See § 703.2 and its subsections for the baseline test/analytic approach.
Altering a listed assembly without substantiation: adding penetrations, finishes or insulating layers to an assembly listed in Table 721.1(1–3) can reduce rating — you must provide tests or data to the building official. § 721.1 warns that materials that change heat dissipation require substantiation.
Using an unlisted calculation standard: § 722.1 names the permitted calculation standards; using other standards without approval is outside the scope of § 722.

Worked example — prescriptive vs. calculated for a steel column

Scenario: You have an exposed steel column that supports primary trusses and you need a 2‑hour fire‑resistance rating.

Prescriptive approach (Section 721):

Find the appropriate row in Table 721.1(1) for "Steel columns and all of primary trusses" and the column for 2‑hour rating. For example, Table 721.1(1) item 1‑1.1 (carbonate, lightweight and sand‑lightweight aggregate concrete protection for members 6" × 6" or greater) shows a minimum insulating thickness of 1½ inches for a 2‑hour rating — if your member and insulating material match that table entry, you may apply that thickness and list the table reference on the construction documents. Use § 721.1 as the basis for assuming the rating.

Calculated approach (Section 722):

Instead of using the table, you may calculate required protection for the steel column using the procedures in § 722 (see § 722.5 for steel assemblies). Per § 722.1 you must follow the listed references (the chapter provides W/D ratio tables and calculation steps such as those in Table 722.5.1(1) for column W/D ratios). Prepare calculations showing the steel section, the protective material thickness (or equivalent), and the computed fire‑resistance duration per the required § 722 method. Submit the calculations to the building official for review. Do not mix the two methods without documenting the basis for doing so.

(Notes: the prescriptive table gives a fast, code‑accepted numeric thickness if your member and protective material match the table entry; the calculated path gives tailored protection that can address nonstandard member sizes or protective systems but requires full calculations per § 722.)

Related provisions

§ 703.2.1 — Test procedures (ASTM E119/UL 263) and the baseline method for tested assemblies; prescriptive and calculated methods are alternative analytical approaches referenced in § 703.2.2.
§ 703.2.2 — Lists prescriptive (Section 721) and calculated (Section 722) among allowed analytical methods.
§ 721.1 — General rules for prescriptive tables and requirement for substantiation when assemblies are altered.
§ 722.1 — Scope and allowed calculation standards for calculated fire resistance.
§ 722.2–722.6 — Material‑specific calculation subsections (concrete, masonry, steel, wood) and associated tables (see the cited tables in the § 722 subsections).

Code references

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

CBC § 501.2 High relevance — show source text
501.2 Objective. The objective of this chapter is to establish minimum standards to locate, design and construct buildings and structures or portions thereof for the protection of life and property, to resist damage from wildfires, and to mitigate building and structure fires from spreading to wildland fuels.

501.3 Fire-resistance-rated construction. Where this code requires 1-hour fire-resistance-rated construction, the fire-resistance rating of building elements, components or assemblies shall be determined in accordance with the test procedures set forth in ASTM E119 or UL 263.

Exceptions:
1. The fire-resistance rating of building elements, components or assemblies based on the prescriptive designs prescribed in Section 721 of the California Building Code .
2. The fire-resistance rating of building elements, components or assemblies based on the calculation procedures in accordance with Section 722 of the California Building Code .
501.4 Noncombustibility tests. The tests indicated in Section 501.4.1 shall serve as criteria for acceptance of noncombustible building materials. 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.

501.4.1 Noncombustible materials. Materials required to be noncombustible shall be tested in accordance with ASTM E136 and pass the test. Alternately, materials required to be noncombustible shall be tested in accordance with ASTM E2652 using the accep- tance 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, and a surfacing of not more than 0.125 inch (3.18 mm) in thick- ness having a flame spread index not greater than 50 when tested in accordance with ASTM E84 or UL 723 shall be acceptable as noncombustible.

SECTION 502— RESERVED

SECTION 503—IGNITION-RESISTANT CONSTRUCTION AND MATERIAL

503.1 General. Buildings and structures hereafter constructed, modified or relocated into or within wildland-urban interface areas shall meet the construction requirements in accordance with Chapter 5 . Materials required to be ignition-resistant building materials shall comply with the requirements of Section 503.2.

Exceptions:

1. New accessory buildings and miscellaneous structures complying with Section 504.11. 2. Additions to and remodels of buildings originally constructed prior to July 1, 2008. 3. Group C occupancy special buildings conforming to the limitations specified in Section 450.4.1 of the California Building Code.

503.2 Ignition-resistant building material. Ignition-resistant building materials shall be designed for exterior use and weather expo- sure and shall comply with any one of the requirements in Section 503.2.1 through 503.2.4.3.3 .

503.2.1 Noncombustible material. Noncombustible material shall comply with the requirements in Section 501.4 .

2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 5-3
CBC § 420.2 High relevance — show source text
Groups I-1, R-1, R-2, R-3 and R-4 420.2 Group I-3 408.7 Supporting construction 708.4.2 Fire Prevention 101.4.5

Fire Protection

Explosion control 414.5.1, 415.6, 421.6, 426.1.4 Fire extinguishers, portable 906 Glazing, rated 716.1.2.3 Smoke and heat removal 910 Smoke control systems 909 Sprinkler systems, automatic 903 Fire Protection Systems Chapter 9, 107.2.2 Fire Protective Curtain Assembly 716.4 Fire Pumps 403.3.2, 902.1, 913, 914.2 Fire Resistance

Calculated 722

Conditions of restraint 703.2.1.3 Ducts and air transfer openings 717 Exterior walls 705.5, Table 705.5,

708.5

Fire district D102.2.5 High-rise 403.2 Joint systems 715 Multiple use fire assemblies 702.1 Prescriptive 721 Ratings Chapter 6, 703, 705.5, 707.3.10 Roof assemblies 1505

Structural members 704

Tests 703 Thermal and sound insulating materials 720.1 Fire Resistance, Calculated 722 Clay brick and tile masonry 722.4 Concrete assemblies 722.2

Concrete masonry 722.3 Steel assemblies 722.5

Wood assemblies 722.6 Fire Separation Distance Table 705.5 Exterior walls

1405.1.1.1.1, 1405.1.1.1.2 Ground-mounted photovoltaic systems 3111.3.6

Fire Service Access Elevators 403.6.1, 3007 Fire Walls 706 Aircraft hangar 412.3.6.2 Combustible framing 706.7 Continuity 706.5, 706.6 Exterior walls Table 705.5, 706.5.1 Fire-resistance rating 703, 706.4 Glazing, rated 716.3.4 Inspection 110.3.8 Joints 706.10, 715 Materials 706.3

Opening protection 706.8, 706.11, 714.4, 716, 717.5.1 Penetration 706.9, 714.4 Special provisions Covered and open mall buildings 402.4.2.2

Group H-5 415.11.1.6 Structural stability 706.2 Fire Windows (see Opening Protectives) Fireblocking 718.2 Chimneys 718.2.5.1, 2113.20 Fireplaces 2111.13 Wood construction 718.2.1, 718.2.7,

1405.1.3 Wood stairways 718.2.4 Fireplaces, Factory-Built 2111.14.1 Fireplaces, Masonry 202 Clearance to combustibles 2111.12

Drawings 2111.2 General provisions 2111 Hearth extension 2111.10, 2111.11 Steel units 2111.6.1

Fire-Resistant Construction 701.1
CBC § 7-21 High relevance — show source text
713 Shaft Enclosures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21

714 Penetrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23

715 Joints and Voids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26

716 Opening Protectives . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-27

717 Ducts and Air Transfer Openings . . . . . . . . . . . . . . . . 7-34

718 Concealed Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-40

719 Fire-Resistance Requirements for Plaster . . . . . . . . 7-42

720 Thermal- and Sound-Insulating Materials . . . . . . . . 7-42

721 Prescriptive Fire Resistance. . . . . . . . . . . . . . . . . . . . . 7-43

722 Calculated Fire Resistance. . . . . . . . . . . . . . . . . . . . . . 7-66

CHAPTER 7A [SFM] MATERIALS AND CONSTRUCTION

METHODS FOR EXTERIOR WILDFIRE EXPOSURE . . . . . . . 7A-1

CHAPTER 8 INTERIOR FINISHES. . . . . . . . . . . . . . . . . . . . . .8-1

801 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

802 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

803 Wall and Ceiling Finishes . . . . . . . . . . . . . . . . . . . . . . . . 8-3

804 Interior Floor Finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

805 Combustible Materials in Types I and II Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

806 Decorative Materials and Trim . . . . . . . . . . . . . . . . . . . 8-7

807 Insulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8

808 Acoustical Ceiling Systems . . . . . . . . . . . . . . . . . . . . . . 8-8

CHAPTER 9 FIRE PROTECTION AND LIFE
CBC § 5-1 High relevance — show source text
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 5-1

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5-2 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE

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5 SPECIAL BUILDING CONSTRUCTION REGULATIONS

User notes:

About this chapter: Chapter 5 provides regulations that establish minimum standards for the location, design and construction of buildings and structures based on construction within a Fire Hazard Severity Zone or a Wildland-Urban Interface (WUI) Area.

The construction provisions of Chapter 5 are intended to supplement the requirements of the California Building Code and California Residential Code and address mitigation of the unique hazards posed to buildings by wildfire and to reduce the hazards of building fires spreading to wildland fuels. This is accomplished by requiring ignition-resistant construction materials. Construction features regulated include underfloor areas; roof coverings; eaves and soffits; gutters and downspouts; exterior walls, doors and windows; ventilation openings and accessory structures.

SECTION 501—GENERAL

501.1 Scope. Buildings and structures in a wildland-urban interface area shall be constructed in accordance with the California Build- ing Code and this code.

Exceptions:
1. Group U accessory structures not exceeding 120 square feet (11 m [2] ) in floor area where located not less than 50 feet (15 240 mm) from applicable buildings.
2. Group U agricultural buildings not less than 50 feet (15 240 mm) from applicable buildings.
501.2 Objective. The objective of this chapter is to establish minimum standards to locate, design and construct buildings and structures or portions thereof for the protection of life and property, to resist damage from wildfires, and to mitigate building and structure fires from spreading to wildland fuels.

501.3 Fire-resistance-rated construction. Where this code requires 1-hour fire-resistance-rated construction, the fire-resistance rating of building elements, components or assemblies shall be determined in accordance with the test procedures set forth in ASTM E119 or UL 263.

Exceptions:
1. The fire-resistance rating of building elements, components or assemblies based on the prescriptive designs prescribed in Section 721 of the California Building Code .
2. The fire-resistance rating of building elements, components or assemblies based on the calculation procedures in accordance with Section 722 of the California Building Code .
501.4 Noncombustibility tests. The tests indicated in Section 501.4.1 shall serve as criteria for acceptance of noncombustible building materials. 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.

501.4.1 Noncombustible materials. Materials required to be noncombustible shall be tested in accordance with ASTM E136 and pass the test. Alternately, materials required to be noncombustible shall be tested in accordance with ASTM E2652 using the accep- tance criteria prescribed by ASTM E136.
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.
1. Fire-resistance designs documented in approved sources.
2. Prescriptive designs of fire-resistance-rated building elements, components or assemblies as prescribed in Section 721.
3. Calculations in accordance with Section 722.
4. 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.
5. Fire-resistance designs certified by an approved agency.
2025 CALIFORNIA BUILDING CODE 7-3

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

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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 § 721.1 Medium relevance — show source text

SECTION 721—PRESCRIPTIVE FIRE RESISTANCE

721.1 General. The provisions of this section contain prescriptive details of fire-resistance-rated building elements, components or assemblies. The materials of construction specified in Tables 721.1(1), 721.1(2) and 721.1(3) shall be assumed to have the fire-resistance ratings prescribed therein. Where materials that change the capacity for heat dissipation are incorporated into a fireresistance-rated assembly, fire test results or other substantiating data shall be made available to the building official to show that the required fire-resistance-rating time period is not reduced.

TABLE 721.1(1)—MINIMUM PROTECTION OF STRUCTURAL PARTS BASED ON TIME PERIODS FOR VARIOUS NONCOMBUSTIBLE INSULATING MATERIALSm	Col2	Col3	Col4	Col5	Col6	Col7
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	4 hours	3 hours	2 hours	1 hour
1. Steel columns and all of primary trusses	1-1.1	Carbonate, lightweight and sand-lightweight aggregate concrete, members 6" × 6" or greater (not including sand- stone, granite and siliceous gravel).a	21/2	2	11/2	1
1. Steel columns and all of primary trusses	1-1.2	Carbonate, lightweight and sand-lightweight aggregate concrete, members 8" × 8" or greater (not including sand- stone, granite and siliceous gravel).a	2	11/2	1	1
1. Steel columns and all of primary trusses	1-1.3	Carbonate, lightweight and sand-lightweight aggregate concrete, members 12" × 12" or greater (not including sand- stone, granite and siliceous gravel).a	11/2	1	1	1
1. Steel columns and all of primary trusses	1-1.4	Siliceous aggregate concrete and concrete excluded in Item 1-1.1, members 6" × 6" or greater.a	3	2	11/2	1
1.

CBC § 7-3 Medium relevance — show source text
702 Multiple-Use Fire Assemblies . . . . . . . . . . . . . . . . . . . . 7-3

703 Fire-Resistance Ratings and Fire Tests . . . . . . . . . . . . 7-3

704 Fire-Resistance Rating of Structural Members . . . . . 7-4

705 Exterior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

706 Fire Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12

707 Fire Barriers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14

708 Fire Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16

709 Smoke Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17

710 Smoke Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18

711 Floor and Roof Assemblies. . . . . . . . . . . . . . . . . . . . . . 7-19

712 Vertical Openings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-20

713 Shaft Enclosures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21

714 Penetrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23

715 Joints and Voids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26

716 Opening Protectives . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-27

717 Ducts and Air Transfer Openings . . . . . . . . . . . . . . . . 7-34

718 Concealed Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-40

719 Fire-Resistance Requirements for Plaster . . . . . . . . 7-42

720 Thermal- and Sound-Insulating Materials . . . . . . . . 7-42

721 Prescriptive Fire Resistance. . . . . . . . . . . . . . . . . . . . . 7-43

722 Calculated Fire Resistance. . . . . . . . . . . . . . . . . . . . . . 7-66

CHAPTER 7A [SFM] MATERIALS AND CONSTRUCTION

METHODS FOR EXTERIOR WILDFIRE EXPOSURE . . . . . . . 7A-1
CBC § 418.4 Medium relevance — show source text
Organic coating 418.4, 418.5, 418.6 Stages and platforms 410.5.1, 410.5.2

Fire Command Center 403.4.6, 412.2.3.2, 911, 3007.7, 3008.6.6, 3008.7 Fire Dampers 717.2, 717.3, 717.4, 717.5 Fire Department (see Emergency Responders) Fire Detection System (see Fire Alarm and Smoke Detection Systems) Fire District Appendix D Fire Door (see Opening Protectives) 716, 1023.4 Fire Escape 412.7.3 Fire Extinguishers, Portable 906, 3309 Fire Extinguishing Systems 416.5, 417.4, 903, 904 Fire Partition 708

Continuity 708.4 Elevator door protection 3006 Exterior walls Table 705.5, 708.5

Fireblocks and draftstops 708.4.3 Fire-resistance rating 603.1, 703, 708.3 Glazing, rated 716.3.4 Inspection 110.3.8 Joint treatment gypsum 2508.5 Joints 708.8, 715 Marking 703.5 Materials 708.2

Opening protection 708.5, 714.4, 716, 717.5.4

Penetrations 708.7, 708.9, 714, 717 Special provisions Covered and open mall buildings 402.4.2.1

Groups I-1, R-1, R-2, R-3 and R-4 420.2 Group I-3 408.7 Supporting construction 708.4.2 Fire Prevention 101.4.5

Fire Protection

Explosion control 414.5.1, 415.6, 421.6, 426.1.4 Fire extinguishers, portable 906 Glazing, rated 716.1.2.3 Smoke and heat removal 910 Smoke control systems 909 Sprinkler systems, automatic 903 Fire Protection Systems Chapter 9, 107.2.2 Fire Protective Curtain Assembly 716.4 Fire Pumps 403.3.2, 902.1, 913, 914.2 Fire Resistance

Calculated 722

Conditions of restraint 703.2.1.3 Ducts and air transfer openings 717 Exterior walls 705.5, Table 705.5,

708.5

Fire district D102.2.5 High-rise 403.2 Joint systems 715 Multiple use fire assemblies 702.1 Prescriptive 721 Ratings Chapter 6, 703, 705.5, 707.3.10 Roof assemblies 1505

Structural members 704

Tests 703 Thermal and sound insulating materials 720.1 Fire Resistance, Calculated 722 Clay brick and tile masonry 722.4 Concrete assemblies 722.2

Concrete masonry 722.3 Steel assemblies 722.5

Wood assemblies 722.6 Fire Separation Distance Table 705.5 Exterior walls
CBC § 2606.5 Medium relevance — show source text
Structural requirements 2606.5 Unprotected openings 2608.1, 2608.2 Veneer, exterior 603.1, 2605 Wall panels 2607 Plastic Glazing 2401.1, 2405.5.2, 2406.1.2 Platform (see Stages and Platforms) 410 Construction 410.3

Temporary 410.3.1 Platform, Equipment (see Equipment Platform) Platform Lifts, Wheelchair Accessibility Chapters 11A and 11B Accessible means of egress 1009.2, 1009.5, Chapters 11A and 11B, 2702.2 Play Structures 424 Accessibility Chapters 11A and 11B Covered and open mall building 402.6.3

Pollutant Control 1212 Ponding Table 1604.3, 1607.14.3.5, 1608.3, 1611.2, 1611.3 Porcelain Tile 1404.11.2, Table 1404.2

Prefabricated Wood I-Joist 2303.1, 2303.1.2, 2308.11.8 Prescriptive Fire Resistance 721 Preservative-treated Wood 202

Fastenings 2304.10.6 Quality 2303.1.9 Required 2304.12 Shakes, roof covering 1507.9.6, 1507.9.8 Private Garage 406.3, 1010.1.2, 1502.3 Accessibility Chapters 11A and 11B Projection Rooms Motion picture 409 Projections, Combustible 705.2.3, 705.2.3.1 Property Line (see Fire Separation Distance)

705.3 Property Maintenance 101.4.4 Proscenium

Curtain 410.2.5

Wall 410.2.4 Psychiatric Hospitals

[see Institutional (see Group I-2)] 308.4 Public Address System (see Emergency Communications) Covered and open mall buildings 402.7, 907.2.20, 2702.2 Special amusement areas 411.3 Public Property Chapter 32, Chapter 33 Public Right-Of-Way Encroachments Chapter 32 Puzzle Room 411 Pyrophoric Materials Table 307.1(1), 307.4

Railing (see Guards And Handrails) Raised-deck System 1511.9 Ramps 1012 Assembly occupancy 1030.14 Construction 1012.2, 1012.5.3, 1012.7,

1012.10

Exit 1023

Exit access 1019

Exterior 1027

CBC § 720.4 Medium relevance — show source text

720.4 Loose-fill insulation. Loose-fill insulation materials that cannot be mounted in the ASTM E84 or UL 723 apparatus without a screen or artificial supports shall comply with the flame spread and smoke-developed limits of Sections 720.2 and 720.3 when tested in accordance with CAN/ULC S102.2.

Exception: Cellulosic fiber loose-fill insulation shall not be required to meet a flame spread index requirement when tested in accordance with CAN/ULC S102.2, provided that such insulation has a smoke-developed index of not more than 450 and complies with the requirements of Section 720.6.

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720.5 Roof insulation. The use of combustible roof insulation not complying with Sections 720.2 and 720.3 shall be permitted in any type of construction provided that insulation is covered with approved roof coverings directly applied thereto.

720.6 Cellulosic fiber loose-fill insulation and self-supported spray-applied cellulosic insulation. Cellulosic fiber loose-fill insulation and self-supported spray-applied cellulosic insulation shall comply with CPSC 16 CFR Parts 1209 and 1404. Each package of such insulating material shall be clearly labeled in accordance with CPSC 16 CFR Parts 1209 and 1404.

720.7 Insulation and covering on pipe and tubing. Insulation and covering on pipe and tubing shall have a flame spread index of not more than 25 and a smoke-developed index of not more than 450.

Exception: Insulation and covering on pipe and tubing installed in plenums shall comply with the California Mechanical Code .

SECTION 721—PRESCRIPTIVE FIRE RESISTANCE

TABLE 721.1(1)—MINIMUM PROTECTION OF STRUCTURAL PARTS BASED ON TIME PERIODS FOR VARIOUS NONCOMBUSTIBLE INSULATING MATERIALSm	Col2	Col3	Col4	Col5	Col6	Col7
STRUCTURAL PARTS TO BE PROTECTED	ITEM NUMBER	INSULATING MATERIAL USED	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL FOR THE FOLLOWING FIRE-RESISTANCE PERIODS (inches)	MINIMUM THICKNESS OF INSULATING MATERIAL **FOR THE FOLLOWING FIRE-RESISTANCE

CBC § 7-65 Medium relevance — show source text
The membrane shall consist of waterproof paper or_ plastic sheets conforming to ASTM C171, Sheet Materials for Curing Concrete, or Type 15 roofing felt conform- ing to ASTM D226, D250 or D227, or Federal Specification UUB790, Building Paper Vegetable Fiber: (Kraft, Waterproofed, Water Repellent and Fire-resistant) Type 1, Grade B. The sheets shall be securely fastened to the subfloor.

2025 CALIFORNIA BUILDING CODE 7-65

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FIRE AND SMOKE PROTECTION FEATURES

3. Regardless of the provisions of Subsections 6.1 and 6.2 in Section 6, of Bulletin No. 65, relating to applicator qualifica- tions and warranty, these subsections are omitted from this chapter.

SECTION 722—CALCULATED FIRE RESISTANCE

722.1 General. The provisions of this section contain procedures by which the fire resistance of specific materials or combinations of materials is established by calculations. These procedures apply only to the information contained in this section and shall not be otherwise used. The calculated fire resistance of specific materials or combinations of materials shall be established by one of the following:
1. Concrete, concrete masonry and clay masonry assemblies shall be permitted in accordance with ACI 216.1/TMS 0216.
2. Precast and precast, prestressed concrete assemblies shall be permitted in accordance with PCI 124.
3. Steel assemblies shall be permitted in accordance with Chapter 5 of ASCE 29.
4. Exposed wood members and wood decking shall be permitted in accordance with Chapter 16 of ANSI/AWC NDS.
722.2 Concrete assemblies. The provisions of this section contain procedures by which the fire-resistance ratings of concrete assemblies are established by calculations.

722.2.1 Concrete walls. Cast-in-place and precast concrete walls shall comply with Section 722.2.1.1. Multiwythe concrete walls shall comply with Section 722.2.1.2. Joints between precast panels shall comply with Section 722.2.1.3. Concrete walls with gypsum wallboard or plaster finish shall comply with Section 722.2.1.4.

722.2.1.1 Cast-in-place or precast walls. The minimum equivalent thicknesses of cast-in-place or precast concrete walls for fireresistance ratings of 1 hour to 4 hours are shown in Table 722.2.1.1. For solid walls with flat vertical surfaces, the equivalent thickness is the same as the actual thickness. The values in Table 722.2.1.1 apply to plain, reinforced or prestressed concrete walls.

|TABLE 722.2.1.1—MINIMUM EQUIVALENT THICKNESS OF
CAST-IN-PLACE OR PRECAST CONCRETE WALLS,
CBC § 73.4 Medium relevance — show source text
Moist cure the specimens for seven days at 73.4°F (40.8°C) plus or minus 3°F_ (1.7°C). At the age of seven days, remove the specimens from the moist condition and store in a temperature of 73.4°F (40.8°C) plus or minus 3°F (1.7°C) and a relative humidity of 50 plus or minus 10 percent for 21 days; remove and air dry until the time of test at 28 days. The compressive strength test shall be in accordance with ASTM C39, Compressive Strength of Cylindrical Concrete Specimens. Determine the air-dry-unit weight at 28 days. 2. Regardless of the provisions of Subsections 4.1 and 4.2 in Section 4 of Bulletin No. 65, relating to placing, finishing and curing, the following shall apply to these regulations. 2.1. The concrete shall be placed, finished and cured to produce a level, smooth surface. The concrete shall be placed in a single layer to a minimum thickness of 1 [1] / 2 inches (38 mm). The deviation from a plan shall not exceed [1] / 4 inch (6 mm) in any 10 feet (3048 mm). The final finish of the concrete shall be suitable for the applica- tion of the specified wear- resistant covering. Cracks wider than [1] / 8 inch (3 mm) shall be repaired. 2.2. Install a water-resistant membrane between wood or plywood subfloors and the cellular concrete to prevent leakage of the concrete and wetting of the subfloor. The membrane shall consist of waterproof paper or plastic sheets conforming to ASTM C171, Sheet Materials for Curing Concrete, or Type 15 roofing felt conform- ing to ASTM D226, D250 or D227, or Federal Specification UUB790, Building Paper Vegetable Fiber: (Kraft, Waterproofed, Water Repellent and Fire-resistant) Type 1, Grade B. The sheets shall be securely fastened to the subfloor.

2025 CALIFORNIA BUILDING CODE 7-65

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

FIRE AND SMOKE PROTECTION FEATURES

3. Regardless of the provisions of Subsections 6.1 and 6.2 in Section 6, of Bulletin No. 65, relating to applicator qualifica- tions and warranty, these subsections are omitted from this chapter.

SECTION 722—CALCULATED FIRE RESISTANCE

722.1 General. The provisions of this section contain procedures by which the fire resistance of specific materials or combinations of materials is established by calculations. These procedures apply only to the information contained in this section and shall not be otherwise used. The calculated fire resistance of specific materials or combinations of materials shall be established by one of the following:
1. Concrete, concrete masonry and clay masonry assemblies shall be permitted in accordance with ACI 216.1/TMS 0216.
2. Precast and precast, prestressed concrete assemblies shall be permitted in accordance with PCI 124.
3. Steel assemblies shall be permitted in accordance with Chapter 5 of ASCE 29.
4. Exposed wood members and wood decking shall be permitted in accordance with Chapter 16 of ANSI/AWC NDS.

Frequently asked questions

Can I mix a prescriptive table thickness with a separate calculation to "tune" the result?

No. You must document which method you are using. If you alter a prescriptive assembly you need test evidence or substantiation to show the rating isn't reduced; if you rely on calculation you must follow the allowed § 722 procedures and submit full calculations. § 721.1 and § 722.1 explain these expectations.

If I add a finish or insulation to a listed 721 assembly, do I have to retest?

Not always retest — but you must provide fire test results or other substantiating data to the building official showing the rating is not reduced when materials that change heat dissipation are added (see § 721.1).

Which standard do I use to calculate fire resistance for concrete walls?

Section 722.1 permits calculations for concrete assemblies in accordance with ACI 216.1/TMS 0216; use § 722.2 and its tables/equations for the detailed procedure.

Are prescriptive tables acceptable evidence of rating for plan review?

Yes—if the assembly exactly matches a table entry in Section 721, that table entry is assumed to provide the prescribed rating; list the table reference on the drawings. If the assembly is modified, provide substantiation.

Where do I find guidance for steel column calculations?

See § 722.5 and Table 722.5.1(1) for W/D ratios and the calculation procedure for steel assemblies; § 722.1 explains which standards apply.

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Related in the CBC

How are fire‑resistance ratings determined and tested?

What fire‑resistance ratings are required for structural members?

Exterior wall fire‑resistance, openings and fire‑separation distance (Table 705.5)

Fire-Resistance‑Rated Construction & Ratings

California Building Code