CRC · California Residential Code

How do flame-spread and smoke-development rules limit wall finishes?

Wall finishes in California homes must be tested and have a flame‑spread index no greater than 200 and a smoke‑developed index no greater than 450 (ASTM E84/UL 723), or meet the NFPA 286 alternative acceptance criteria; short trim pieces and very thin applied materials have limited exceptions. Provide test reports to the building official and follow installation rules in § R702.1 and the performance limits in § R302.9. file

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Last reviewed: July 6, 2026

What the code requires — plain English

Wall and ceiling finish materials in California dwellings must meet limits on how fast they burn (flame spread index ≤ 200) and how much smoke they produce (smoke-developed index ≤ 450), tested by ASTM E84 or UL 723, unless they meet the NFPA 286 acceptance criteria or an explicit exception applies (§ R302.9) . Interior coverings and finishes also must be installed per the Interior Covering rules and conform to those flame‑spread/smoke limits (§ R702.1) .

The single essential rule: wall and ceiling finishes must not contribute excessive flame spread or smoke — keep flame spread ≤ 200 and smoke development ≤ 450, unless an approved test or narrow exception applies. § R302.9

Requirements in detail

Key defined terms (first mention bolded)

  • Flame spread index — a numerical rating from the ASTM E84 / UL 723 tunnel test that indicates how quickly flame spreads across a surface. § R302.9.1
  • Smoke‑developed index — the ASTM E84 / UL 723 measure of smoke production during the same tunnel test. § R302.9.2
  • NFPA 286 — an alternate room‑corner/full‑scale test that may be used in lieu of the tunnel test when specific acceptance criteria are met. § R302.9.4

Decision‑relevant dimensions and values

Decision dimension Required limit / value When it applies Code Reference
Maximum flame spread index for wall/ceiling finishes 200 Default requirement for wall/ceiling finishes in dwellings § R302.9.1
Maximum smoke‑developed index 450 Default requirement for wall/ceiling finishes § R302.9.2
ASTM E84 / UL 723 test method Required test method for indices Standard testing route for compliance § R302.9.3
NFPA 286 acceptance (alternate) — peak heat release ≤ 800 kW If using NFPA 286 as alternative to ASTM E84/UL 723 § R302.9.4 and Building Code §803.1.1.1
NFPA 286 acceptance — total smoke released ≤ 1,000 m² (total smoke) NFPA 286 acceptance criterion § R302.9.4 and Building Code §803.1.1.1
NFPA 286 acceptance — flame spread to ceiling No flame spread to ceiling during 40 kW exposure NFPA 286 acceptance criterion § R302.9.4
Thin‑material exemption (thickness) Materials < 1/28 in (0.91 mm) may be exempt from flame‑spread rule (with conditions) Trim/very thin applied materials exception § R302.9.1 Exception

How the two controlling sections interact

  • § R702.1 requires interior coverings to be installed per Chapter 7 and explicitly states interior finishes must conform to § R302.9 (the flame‑spread/smoke rules) — so installation rules and finish performance rules are linked .
  • § R302.9 sets the performance thresholds and test methods; it also permits NFPA 286 as an alternative compliance route and lists limited exceptions (trim, very thin cemented materials) .

Exceptions & special cases

  • Trim items such as picture molds, chair rails, baseboards and handrails, and doors/windows or their frames are exempt from the flame‑spread requirement described in § R302.9.1 (but other provisions may apply) .
  • Materials thinner than 1/28 inch (0.91 mm) when cemented to the surface may be exempt if they exhibit flame spread no worse than paper of that thickness on a noncombustible backing (§ R302.9.1 Exception) .
  • The code allows the NFPA 286 test as an alternative to ASTM E84/UL 723; NFPA 286 compliance requires specific performance in a room‑corner exposure (no ceiling spread during the 40 kW exposure; no outer extremity spread; no flashover; heat‑release and total‑smoke criteria) — see § R302.9.4 and the Building Code acceptance criteria in §803.1.1.1 .
  • Certain materials (for example HDPE or polypropylene used as interior finish) must be evaluated by NFPA 286 per § R302.9.5 (special rule for those plastics) .
  • Stability/attachment: finishes regulated here must be applied so they will not readily detach when exposed to room temperatures of 200°F (93°C) for not less than 30 minutes (stability requirement) — see the related stability language tied into the NFPA acceptance provisions (see § R302.9.4.1) .

Note: For foam‑plastic specifics or interior trim area limits, see the separate provisions in Chapter R303 and R804 (these are related but distinct rules) file.

Common mistakes

  • Treating ASTM E84 class (A/B/C) as the only path and ignoring the NFPA 286 alternative — NFPA 286 can be used when its acceptance criteria are met (§ R302.9.4) .
  • Assuming all wood or “solid” paneling is automatically acceptable — many wood products exceed 200 flame spread and must be verified by test data. The code’s numeric limits control, not the material name (§ R302.9.1–.3) .
  • Overlooking the smoke‑developed index ≤ 450 limit — some installers focus only on flame spread and forget the smoke criterion (§ R302.9.2) .
  • Ignoring the thin‑material and trim exceptions’ conditions — e.g., a vinyl sheet under 0.91 mm may be exempt only if it behaves like paper of that thickness on a noncombustible backing (§ R302.9.1 Exception) .
  • Failing to verify test reports reference the correct standard and specimen mountings; ASTM E84/UL 723 and NFPA 286 are not interchangeable without meeting the specific alternative criteria (§ R302.9.3–.4) .

Worked example — concrete scenario with numbers

Scenario: You plan to install a decorative polymer wall panel in a hallway of a single‑family dwelling.

  1. Obtain the manufacturer’s test report. If the panel is tested by ASTM E84 and the report shows flame spread index = 120 and smoke‑developed index = 300, the product meets the numeric limits in § R302.9.1 and § R302.9.2 (≤ 200 and ≤ 450) — acceptable for installation per § R702.1 file.
  2. If the ASTM E84 report instead shows flame spread = 220 and smoke = 320, the product fails the tunnel test flame spread limit. You may still seek compliance by testing to NFPA 286 and demonstrating the acceptance criteria are met (no ceiling spread during the 40 kW exposure; no outer extremity spread; no flashover; peak heat release ≤ 800 kW; total smoke ≤ 1,000 m²) — see § R302.9.4 and Building Code §803.1.1.1 file.
  3. If it is thin trim (< 1/28 in) applied as molding, check the trim exception language before assuming compliance — the thickness and comparative paper test conditions control (§ R302.9.1 Exception) .

Related provisions (quick references)

  • § R702.1 — Interior covering general rule; ties finishes to flame‑spread/smoke requirements .
  • § R302.9.1–.4 — Flame spread, smoke limits, testing, NFPA 286 alternative (primary controlling section) .
  • § R303 — Rules for foam plastics used as interior finishes (special limits and testing) — see R303.3 and R303.5.10 for applicability and testing details .
  • Building Code § 803.1.1.1 — NFPA 286 acceptance criteria and numeric heat/smoke limits (expanded explanation of NFPA route) .
  • § R804 / Building Code §804 — Interior trim provisions (area/size and flame spread limits for trim) for situations where trim rules apply .

Code references

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

  • CRC § 803.1 High relevance — show source text

    INTERIOR FINISH, DECORATIVE MATERIALS AND FURNISHINGS

    SECTION 803—INTERIOR WALL AND CEILING FINISH IN EXISTING BUILDINGS

    803.1 General. The provisions of this section shall limit the allowable fire performance and smoke development of interior wall and ceiling finishes in existing buildings based on location and occupancy classification. Interior wall and ceiling finishes shall be classified in accordance with Section 803 of the California Building Code . Such materials shall be classified in accordance with NFPA 286, as indicated in Section 803.1.1, or in accordance with ASTM E84 or UL 723, as indicated in Section 803.1.2.

    Materials tested in accordance with Section 803.1.1 shall not be required to be tested in accordance with Section 803.1.2.

    803.1.1 Interior wall and ceiling finish materials tested in accordance with NFPA 286. Interior wall and ceiling finish materials shall be classified in accordance with NFPA 286 and tested in accordance with Section 803.1.1.1. Materials complying with Section 803.1.1.1 shall be considered to comply with the requirements of Class A specified in Section 803.1.2.

    803.1.1.1 Acceptance criteria for NFPA 286. The interior finish shall comply with the following:

    1. During the 40 kW exposure, flames shall not spread to the ceiling.

    2. The flame shall not spread to the outer extremity of the sample on any wall or ceiling.

    3. Flashover, as defined in NFPA 286, shall not occur.

    4. The peak heat release rate throughout the test shall not exceed 800 kW.

    5. The total smoke released throughout the test shall not exceed 1,000 m [2] .

    803.1.2 Interior wall and ceiling finish materials tested in accordance with ASTM E84 or UL 723. Interior wall and ceiling finishes shall be classified in accordance with ASTM E84 or UL 723. Such interior finish materials shall be grouped in the following classes in accordance with their flame spread and smoke-developed indices: Class A: Flame spread index 0–25; smoke-developed index 0–450. Class B: Flame spread index 26–75; smoke-developed index 0–450. Class C: Flame spread index 76–200; smoke-developed index 0–450.

    Exception: Materials tested in accordance with Section 803.1.1 and as indicated in Sections 803.1.3 through 803.15.

    803.1.3 Interior wall and ceiling finish materials with specific requirements. The materials indicated in Sections 803.4 through 803.15 shall be tested as indicated in the corresponding sections.

    803.2 Stability. Interior finish materials regulated by this chapter shall be applied or otherwise fastened in such a manner that such materials will not readily become detached where subjected to room temperatures of 200°F (93°C) for not less than 30 minutes.

    803.3 Interior finish requirements based on occupancy. Interior wall and ceiling finish shall have a flame spread index not greater than that specified in Table 803.3 for the group and location designated. Interior wall and ceiling finish materials tested in accordance with NFPA 286, and meeting the acceptance criteria of Section 803.1.1.1, shall be used where a Class A classification in accordance with ASTM E84 or UL 723 is required.

    |TABLE 803.

  • CRC § 3-27 High relevance — show source text

    2025 CALIFORNIA RESIDENTIAL CODE 3-27

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    BUILDING PLANNING

    TABLE R302.6—DWELLING UNIT GARAGE AND/OR CARPORT SEPARATION Col2
    ** SEPARATION** ** MATERIAL**
    From the dwelling unit and attics Not less than1/2-inch gypsum board or equivalent applied to the garage side
    From portions of the dwelling unit above the garage_or carport_ Not less than5/8-inch Type X gypsum board or equivalent
    Structure supporting floor/ceiling assemblies used for separation
    required by this section    		 Not less than1/2-inch gypsum board or equivalent
    Garages located less than 3 feet from a dwelling unit on the same lot Not less than1/2-inch gypsum board or equivalent applied to the interior
    side of exterior walls that are within this area
    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm. For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

    R302.7 Under-stair protection. Enclosed space under stairs that is accessed by a door or access panel shall have walls, under-stair surface and any soffits protected on the enclosed side with [1] / 2 -inch (12.7 mm) gypsum board.

    R302.8 Foam plastics. For requirements for foam plastics, see Section R303.

    R302.8.1 Interior finish. Foam plastics used as interior finishes shall comply with Section R303.5.10.

    R302.9 Flame spread index and smoke-developed index for wall and ceiling finishes. Flame spread and smoke-developed indices for wall and ceiling finishes shall be in accordance with Sections R302.9.1 through R302.9.4.

    R302.9.1 Flame spread index. Wall and ceiling finishes shall have a flame spread index of not greater than 200.

    Exception: Flame spread index requirements for finishes shall not apply to trim defined as picture molds, chair rails, baseboards and handrails; to doors and windows or their frames; or to materials that are less than [1] / 28 inch (0.91 mm) in thickness cemented to the surface of walls or ceilings if these materials exhibit flame spread index values not greater than those of paper of this thickness cemented to a noncombustible backing.

    R302.9.2 Smoke-developed index. Wall and ceiling finishes shall have a smoke-developed index of not greater than 450.

    R302.9.3 Testing. Tests shall be made in accordance with ASTM E84 or UL 723.

    R302.9.4 Alternative test method. As an alternative to having a flame spread index of not greater than 200 and a smoke-developed index of not greater than 450 where tested in accordance with ASTM E84 or UL 723, wall and ceiling finishes shall be permitted to be tested in accordance with NFPA 286. Materials tested in accordance with NFPA 286 shall meet the following criteria:

    The interior finish shall comply with the following:

    1. During the 40 kW exposure, flames shall not spread to the ceiling.
    2. The flame shall not spread to the outer extremity of the sample on any wall or ceiling.
    3. Flashover, as defined in NFPA 286, shall not occur.
  • CRC § 803.1.2 High relevance — show source text

    803.1.2 Interior wall and ceiling finish materials tested in accordance with ASTM E84 or UL 723. Interior wall and ceiling finishes shall be classified in accordance with ASTM E84 or UL 723. Such interior finish materials shall be grouped in the following classes in accordance with their flame spread and smoke-developed indices: Class A: Flame spread index 0–25; smoke-developed index 0–450. Class B: Flame spread index 26–75; smoke-developed index 0–450. Class C: Flame spread index 76–200; smoke-developed index 0–450.

    Exception: Materials tested in accordance with Section 803.1.1 and as indicated in Sections 803.1.3 through 803.15.

    803.1.3 Interior wall and ceiling finish materials with specific requirements. The materials indicated in Sections 803.4 through 803.15 shall be tested as indicated in the corresponding sections.

    803.2 Stability. Interior finish materials regulated by this chapter shall be applied or otherwise fastened in such a manner that such materials will not readily become detached where subjected to room temperatures of 200°F (93°C) for not less than 30 minutes.

    803.3 Interior finish requirements based on occupancy. Interior wall and ceiling finish shall have a flame spread index not greater than that specified in Table 803.3 for the group and location designated. Interior wall and ceiling finish materials tested in accordance with NFPA 286, and meeting the acceptance criteria of Section 803.1.1.1, shall be used where a Class A classification in accordance with ASTM E84 or UL 723 is required.

    TABLE 803.3—INTERIOR WALL AND CEILING FINISH REQUIREMENTS BY OCCUPANCYk Col2 Col3 Col4 Col5 Col6 Col7
    GROUP SPRINKLEREDl SPRINKLEREDl SPRINKLEREDl NONSPRINKLERED NONSPRINKLERED NONSPRINKLERED
    GROUP Interior exit stair-
    ways and ramps
    and exit passage-
    waysa, b    		 Corridors and enclosure
    for exit access stairways
    and ramps    		 Rooms and
    enclosed
    spacesc    		 Interior exit stair-
    ways and ramps and
    exit passagewaysa, b    		 Corridors and
    enclosure for exit
    access stairways and
    ramps    		 Rooms and
    enclosed
    spacesc
    A-1 and A-2 B B C A Ad Be
    A-3f, A-4, A-5 B B C A Ad C
    B, E, M, R-1, R-4 B Cm C A Bm C
    F C C C B C C
    H_, L_ B B Cg A A B
    I-1 B C C A B B
    I-3 A Aj C A A B
    I-4 B B Bh,
  • CRC § 5.5 High relevance — show source text

    [BSC-CG] See California Green Building Standards Code, Chapter 5, Division 5.5 for additional finish material pollutant control requirements.

    SECTION 802—GENERAL

    802.1 Interior wall and ceiling finish. The provisions of Section 803 shall limit the allowable fire performance and smoke development of interior wall and ceiling finish materials based on occupancy classification.

    802.2 Interior floor finish. The provisions of Section 804 shall limit the allowable fire performance of interior floor finish materials based on occupancy classification.

    [F] 802.3 Decorative materials and trim. Decorative materials and trim shall be restricted by combustibility, fire performance or flame propagation performance criteria in accordance with Section 806.

    802.4 Applicability. For buildings in flood hazard areas as established in Section 1612.3, interior finishes, trim and decorative materials below the elevation required by Section 1612 shall be flood-damage-resistant materials.

    802.5 Application. Combustible materials shall be permitted to be used as finish for walls, ceilings, floors and other interior surfaces of buildings.

    802.6 Windows. Show windows in the exterior walls of the first story above grade plane shall be permitted to be of wood or of unprotected metal framing.

    802.7 Foam plastics. Foam plastics shall not be used as interior finish except as provided in Section 803.4. Foam plastics shall not be used as interior trim except as provided in Section 806.6.1 or 2604.2. This section shall apply both to exposed foam plastics and to foam plastics used in conjunction with a textile or vinyl facing or cover.

    SECTION 803—WALL AND CEILING FINISHES

    803.1 General. Interior wall and ceiling finish materials shall be classified for fire performance and smoke development in accordance with Section 803.1.1 or 803.1.2, except as shown in Sections 803.1.3 through 803.15. Materials tested in accordance with Section 803.1.1 shall not be required to be tested in accordance with Section 803.1.2.

    803.1.1 Interior wall and ceiling finish materials tested in accordance with NFPA 286. Interior wall and ceiling finish materials shall be classified in accordance with NFPA 286 and comply with Section 803.1.1.1. Materials complying with Section 803.1.1.1 shall be considered to also comply with the requirements of Class A.

    803.1.1.1 Acceptance criteria for NFPA 286. The interior finish shall comply with the following:

    1. During the 40 kW exposure, flames shall not spread to the ceiling.

    2. The flame shall not spread to the outer extremity of the sample on any wall or ceiling.

    3. Flashover, as defined in NFPA 286, shall not occur.

    4. The peak heat release rate throughout the test shall not exceed 800 kW.

    5. The total smoke released throughout the test shall not exceed 1,000 m [2] .

    803.1.2 Interior wall and ceiling finish materials tested in accordance with ASTM E84 or UL 723. Interior wall and ceiling finish materials shall be classified in accordance with ASTM E84 or UL 723. Such interior finish materials shall be grouped in the following classes in accordance with their flame spread and smoke-developed indices.

    Class A = Flame spread index 0–25; smoke-developed index 0–450.

    Class B = Flame spread index 26–75; smoke developed index 0–450.

    Class C = Flame spread index 76–200; smoke-developed index 0–450.

  • CRC § 9.1 High relevance — show source text

    R302.9 Flame spread index and smoke-developed index for wall and ceiling finishes. Flame spread and smoke-developed indices for wall and ceiling finishes shall be in accordance with Sections R302.9.1 through R302.9.4.

    R302.9.1 Flame spread index. Wall and ceiling finishes shall have a flame spread index of not greater than 200.

    Exception: Flame spread index requirements for finishes shall not apply to trim defined as picture molds, chair rails, baseboards and handrails; to doors and windows or their frames; or to materials that are less than [1] / 28 inch (0.91 mm) in thickness cemented to the surface of walls or ceilings if these materials exhibit flame spread index values not greater than those of paper of this thickness cemented to a noncombustible backing.

    R302.9.2 Smoke-developed index. Wall and ceiling finishes shall have a smoke-developed index of not greater than 450.

    R302.9.3 Testing. Tests shall be made in accordance with ASTM E84 or UL 723.

    R302.9.4 Alternative test method. As an alternative to having a flame spread index of not greater than 200 and a smoke-developed index of not greater than 450 where tested in accordance with ASTM E84 or UL 723, wall and ceiling finishes shall be permitted to be tested in accordance with NFPA 286. Materials tested in accordance with NFPA 286 shall meet the following criteria:

    The interior finish shall comply with the following:

    1. During the 40 kW exposure, flames shall not spread to the ceiling.

    2. The flame shall not spread to the outer extremity of the sample on any wall or ceiling.

    3. Flashover, as defined in NFPA 286, shall not occur.

    4. The peak heat release rate throughout the test shall not exceed 800 kW.

    5. The total smoke released throughout the test shall not exceed 1,000 m [2] .

    R302.9.4.1 Stability. Interior finish materials regulated by this chapter shall be applied or otherwise fastened in such a manner that such materials will not readily become detached where subjected to room temperatures of 200°F (93°C) for not less than 30 minutes.

    R302.9.5 High-density polyethylene (HDPE) and polypropylene (PP). Where high-density polyethylene or polypropylene is used as an interior finish material, it shall be tested in accordance with NFPA 286 and comply with the criteria in Section R302.9.4.

    R302.10 Flame spread index and smoke-developed index for insulation. Flame spread and smoke-developed index for insulation shall be in accordance with Sections R302.10.1 through R302.10.4.

    R302.10.1 Insulation. Insulating materials installed within floor-ceiling assemblies, roof-ceiling assemblies, wall assemblies, crawl spaces and attics shall comply with the requirements of this section. They shall exhibit a flame spread index not to exceed 25 and a smoke-developed index not to exceed 450 where tested in accordance with ASTM E84 or UL 723. Insulating materials, where tested in accordance with the requirements of this section, shall include facings, where used, such as vapor retarders, vapor permeable membranes and similar coverings.

    Exceptions:

  • CRC § 803.13 High relevance — show source text

    1||X||||||||||||||||||||||| |Table 803.13|||X|||||||||||||||||||||| |804.1|||X|||||||||||||||||||||| |804.4|||X|||||||||||||||||||||| |804.4.1|||X|||||||||||||||||||||| |804.4.2|||X|||||||||||||||||||||| |804.4.3|||X|||||||||||||||||||||| |806.4|||X|||||||||||||||||||||| |806.6|||X||||||||||||||||||||||

    The state agency does not adopt sections identified by the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

    2025 CALIFORNIA BUILDING CODE 8-1

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    8-2 2025 CALIFORNIA BUILDING CODE

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    8 INTERIOR FINISHES

    User notes:

    About this chapter: Chapter 8 contains the performance requirements for controlling fire growth and smoke propagation within buildings by restricting interior finish and decorative materials. The provisions of this chapter require materials used as interior finishes and decorations to meet certain flame spread index or flame propagation criteria and smoke development criteria based on the relative fire hazard associated with the occupancy. The performance of the material is evaluated based on test standards.

    SECTION 801—SCOPE

    801.1 Scope. The provisions of this chapter shall govern the use of materials used as interior finishes, trim and decorative materials.

    [BSC-CG] See California Green Building Standards Code, Chapter 5, Division 5.5 for additional finish material pollutant control requirements.

    SECTION 802—GENERAL

    802.1 Interior wall and ceiling finish. The provisions of Section 803 shall limit the allowable fire performance and smoke development of interior wall and ceiling finish materials based on occupancy classification.

    802.2 Interior floor finish. The provisions of Section 804 shall limit the allowable fire performance of interior floor finish materials based on occupancy classification.

    [F] 802.3 Decorative materials and trim. Decorative materials and trim shall be restricted by combustibility, fire performance or flame propagation performance criteria in accordance with Section 806.

    802.4 Applicability. For buildings in flood hazard areas as established in Section 1612.3, interior finishes, trim and decorative materials below the elevation required by Section 1612 shall be flood-damage-resistant materials.

    802.5 Application. Combustible materials shall be permitted to be used as finish for walls, ceilings, floors and other interior surfaces of buildings.

    802.6 Windows. Show windows in the exterior walls of the first story above grade plane shall be permitted to be of wood or of unprotected metal framing.

    802.7 Foam plastics. Foam plastics shall not be used as interior finish except as provided in Section 803.4. Foam plastics shall not be used as interior trim except as provided in Section 806.6.1 or 2604.2. This section shall apply both to exposed foam plastics and to foam plastics used in conjunction with a textile or vinyl facing or cover.

    SECTION 803—WALL AND CEILING FINISHES

  • CRC § 802.1 High relevance — show source text

    SECTION 802—DEFINITIONS

    802.1 Definitions. The following terms are defined in Chapter 2:

    FLAME SPREAD.

    FLAME SPREAD INDEX.

    INTERIOR FLOOR-WALL BASE.

    SITE-FABRICATED STRETCH SYSTEM.

    SMOKE-DEVELOPED INDEX.

    [California Code of Regulations, Title 19, Division 1, §1191] Approved.

    “Approved” means approved by the State Fire Marshal.

    [California Code of Regulations, Title 19, Division 1, §1196] Flame-retardant Chemical.

    “Flame-Retardant Chemical,” as used herein, means any chemical, chemical compound or chemical mixture which when properly applied to a fabric or material will render such fabric or material incapable of supporting combustion to the extent that it will success- fully withstand the tests and meet the specifications promulgated by the State Fire Marshal.

    [California Code of Regulations, Title 19, Division 1, §1201] Nonflammable Material.

    “Nonflammable Material,” as used herein, means a fabric or material which is inherently flame-resistant to the extent that it will meet the requirements of the fire resistance test herein prescribed, but shall not include materials which must be chemically treated or processed after manufacture to make them flame-resistant.

    [California Code of Regulations, Title 19, Division 1, §1202] Place of Public Assemblage.

    “Place of Public Assemblage,” as used herein, means any occupancy mentioned in Sections 13115 or 13119 of the Health and Safety Code.

    2025 CALIFORNIA FIRE CODE 8-3

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    INTERIOR FINISH, DECORATIVE MATERIALS AND FURNISHINGS

    SECTION 803—INTERIOR WALL AND CEILING FINISH IN EXISTING BUILDINGS

    803.1 General. The provisions of this section shall limit the allowable fire performance and smoke development of interior wall and ceiling finishes in existing buildings based on location and occupancy classification. Interior wall and ceiling finishes shall be classified in accordance with Section 803 of the California Building Code . Such materials shall be classified in accordance with NFPA 286, as indicated in Section 803.1.1, or in accordance with ASTM E84 or UL 723, as indicated in Section 803.1.2.

    Materials tested in accordance with Section 803.1.1 shall not be required to be tested in accordance with Section 803.1.2.

    803.1.1 Interior wall and ceiling finish materials tested in accordance with NFPA 286. Interior wall and ceiling finish materials shall be classified in accordance with NFPA 286 and tested in accordance with Section 803.1.1.1. Materials complying with Section 803.1.1.1 shall be considered to comply with the requirements of Class A specified in Section 803.1.2.

    803.1.1.1 Acceptance criteria for NFPA 286. The interior finish shall comply with the following:

    1. During the 40 kW exposure, flames shall not spread to the ceiling.

    2. The flame shall not spread to the outer extremity of the sample on any wall or ceiling.

    3. Flashover, as defined in NFPA 286, shall not occur.

    4. The peak heat release rate throughout the test shall not exceed 800 kW.

    5. The total smoke released throughout the test shall not exceed 1,000 m [2] .

  • CRC § 5.6 High relevance — show source text

    R303.5.6 Foam-filled garage doors. Foam-filled garage doors in attached or detached garages are exempt from the requirements of Sections R303.3 and R303.4.

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    BUILDING PLANNING

    R303.5.7 Foam backer board. The thermal barrier specified in Section R303.4 is not required where siding backer board foam plastic insulation has a thickness of not more than 0.5 inch (12.7 mm) and a potential heat of not more than 2000 Btu per square foot (22 720 kJ/m [2] ) when tested in accordance with NFPA 259 and it complies with one or more of the following:

    1. The foam plastic insulation is separated from the interior of the building by not less than 2 inches (51 mm) of mineral fiber insulation.

    2. The foam plastic insulation is installed over existing exterior wall finish in conjunction with re-siding.

    3. The foam plastic insulation has been tested in accordance with Section R303.6.

    R303.5.8 Re-siding. The thermal barrier specified in Section R303.4 is not required where the foam plastic insulation is installed over existing exterior wall finish in conjunction with re-siding provided that the foam plastic has a thickness of not more than 0.5 inch (12.7 mm) and a potential heat of not more than 2000 Btu per square foot (22 720 kJ/m [2] ) when tested in accordance with NFPA 259.

    R303.5.9 Interior trim. The thermal barrier specified in Section R303.4 is not required for exposed foam plastic interior trim, provided that all of the following are met:

    1. The density is not less than 20 pounds per cubic foot (320 kg/m [3] ).
    2. The thickness of the trim is not more than 0.5 inch (12.7 mm) and the width is not more than 8 inches (204 mm).
    3. The interior trim shall not constitute more than 10 percent of the aggregate wall and ceiling area of any room or space.
    4. The flame spread index does not exceed 75 when tested in accordance with ASTM E84 or UL 723. The smoke-developed index is not limited.

    R303.5.10 Interior finish. Foam plastics used as interior finishes shall comply with Section R303.6 and shall meet the flame spread index and smoke-developed index requirements of Sections R302.9.1 and R302.9.2.

    R303.5.11 Sill plates and headers. Foam plastic spray applied to sill plates and headers or installed in the perimeter joist space without the thermal barrier specified in Section R303.4 shall comply with all of the following:

    1. The thickness of the foam plastic shall be not more than 3 [1] / 4 inches (83 mm).
    2. The density of the foam plastic shall be in the range of 0.5 to 2.0 pounds per cubic foot (8 to 32 kg/m [3] ).
    3. The foam plastic shall have a flame spread index of 25 or less and an accompanying smoke-developed index of 450 or less when tested in accordance with ASTM E84 or UL 723.
  • CRC § 3.5. High relevance — show source text

    SECTION R702—INTERIOR COVERING

    R702.1 General. Interior coverings or wall finishes shall be installed in accordance with this chapter and Tables R702.1(1), R702.1(2), R702.1(3) and R702.3.5. Interior masonry veneer shall comply with the requirements of Section R703.7.1 for support and Section R703.7.4 for anchorage, except an airspace is not required. Interior finishes and materials shall conform to the flame spread and smoke-development requirements of Section R302.9.

    **

    TABLE R702.1(1)—THICKNESS OF PLASTER Col2 Col3
    ** PLASTER BASE** ** FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE**
    (inches)    		 ** FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE**
    (inches)
    ** PLASTER BASE** ** Gypsum Plaster** ** Cement Plaster**
    Expanded metal lath 5/8, minimuma 5/8, minimuma
    Wire lath 5/8, minimuma 3/4, minimum (interior)b
    Wire lath 5/8, minimuma 7/8, minimum (exterior)b
    Gypsum lathg 1/2, minimum 3/4, minimum (interior)b
    Masonry wallsc 1/2, minimum 1/2, minimum
    Monolithic concrete wallsc, d 5/8, maximum 7/8, maximum
    Monolithic concrete ceilingsc, d 3/8, maximume 1/2, maximum
    Gypsum veneer basef, g 1/16, minimum 3/4, minimum (interior)b
    Gypsum sheathingg — 3/4, minimum (interior)b
    Gypsum sheathingg — 7/8, minimum (exterior)b
    For SI: 1 inch = 25.4 mm.
    a. Where measured from back plane of expanded metal lath, exclusive of ribs, or self-furring lath, plaster thickness shall be3/4 inch minimum.
    b. Where measured from face of support or backing.
    c. Because masonry and concrete surfaces vary in plane, thickness of plaster need not be uniform.
    d. Where applied over a liquid bonding agent, finish coat shall be permitted to be applied directly to concrete surface.
    e. Approved acoustical plaster shall be permitted to be applied directly to concrete or over base coat plaster, beyond the maximum plaster thickness shown.
    f. Attachment shall be in accordance with Table R702.3.5.
    g. Where gypsum board is used as a base for cement plaster, a water-resistive barrier complying with Section R703.2 shall be provided.    		 For SI: 1 inch = 25.4 mm.
    a. Where measured from back plane of expanded metal lath, exclusive of ribs, or self-furring lath, plaster thickness shall be3/4 inch minimum.
    b. Where measured from face of support or backing.
    c. Because masonry and concrete surfaces vary in plane, thickness of plaster need not be uniform.
    d. Where applied over a liquid bonding agent, finish coat shall be permitted to be applied directly to concrete surface.
    e. Approved acoustical plaster shall be permitted to be applied directly to concrete or over base coat plaster, beyond the maximum plaster thickness shown.
    f.
  • CRC § 803.5.1.1 High relevance — show source text

    803.5.1.1 Acceptance criteria for NFPA 265 Method B test protocol. Where testing to NFPA 265, the interior finish shall comply with the following:

    1. During the 40-kW exposure, flames shall not spread to the ceiling.
    2. The flame shall not spread to the outer extremities of the samples on the 8-foot by 12-foot (203 by 305 mm) walls.
    3. Flashover, as defined in NFPA 265, shall not occur.
    4. For newly introduced wall coverings, the total smoke released throughout the test shall not exceed 1,000 m [2] .

    803.5.1.2 Unframed rigid combustible decorative material. Rigid combustible decorative material and assemblies of materials not more than [1] / 4 inch in thickness used for folding doors, room dividers, decorative screens and similar applications, which do not create concealed spaces and which are installed with exposed edges, shall be flame resistant in accordance with SFM Standard 12-7-5 contained in Title 24, Part 12, California Referenced Standards Code.

    803.5.1.3 Framed rigid combustible decorative material. Rigid combustible decorative material and assemblies of materials not more than [1] / 4 inch in thickness used for folding doors, room dividers, decorative screens and similar applications, and which are installed with all edges protected, shall conform to SFM Standard 12-7-5 contained in Title 24, Part 12, California Referenced Standards Code.

    803.5.2 Acceptance criteria for wall and ceiling coverings. Textile wall and ceiling coverings shall have a Class A flame spread index in accordance with ASTM E84 or UL 723, and be protected by an automatic sprinkler system installed in accordance with Section 903.3.1.1 or 903.3.1.2. Test specimen preparation and mounting shall be in accordance with ASTM E2404.

    803.6 Textile ceiling coverings. Where used as interior ceiling finish materials, textile ceiling coverings, including materials having a woven, nonwoven, napped, tufted, looped or similar surface and carpet or similar textile materials, shall be tested in the manner intended for use, using the product mounting system, including adhesive, and shall comply with the requirements of Section 803.1.1 or 803.5.2.

    803.7 Expanded vinyl wall coverings. Where used as interior wall finish materials, expanded vinyl wall coverings shall be tested in the manner intended for use, using the product mounting system, including adhesive, and shall comply with the requirements of Section 803.1.1, 803.5.1 or 803.5.2.

    803.8 Expanded vinyl ceiling coverings. Where used as interior ceiling finish materials, expanded vinyl ceiling coverings shall be tested in the manner intended for use, using the product mounting system, including adhesive, and shall comply with the requirements of Section 803.1.1 or 803.5.2.

    [BF] 803.9 High-density polyethylene (HDPE) and polypropylene (PP). Where high-density polyethylene or polypropylene is used as an interior finish, it shall comply with Section 803.1.1.

  • CRC § 803.1.1 Medium relevance — show source text

    803.1.1 Interior wall and ceiling finish materials tested in accordance with NFPA 286. Interior wall and ceiling finish materials shall be classified in accordance with NFPA 286 and comply with Section 803.1.1.1. Materials complying with Section 803.1.1.1 shall be considered to also comply with the requirements of Class A.

    803.1.1.1 Acceptance criteria for NFPA 286. The interior finish shall comply with the following:

    1. During the 40 kW exposure, flames shall not spread to the ceiling.

    2. The flame shall not spread to the outer extremity of the sample on any wall or ceiling.

    3. Flashover, as defined in NFPA 286, shall not occur.

    4. The peak heat release rate throughout the test shall not exceed 800 kW.

    5. The total smoke released throughout the test shall not exceed 1,000 m [2] .

    803.1.2 Interior wall and ceiling finish materials tested in accordance with ASTM E84 or UL 723. Interior wall and ceiling finish materials shall be classified in accordance with ASTM E84 or UL 723. Such interior finish materials shall be grouped in the following classes in accordance with their flame spread and smoke-developed indices.

    Class A = Flame spread index 0–25; smoke-developed index 0–450.

    Class B = Flame spread index 26–75; smoke developed index 0–450.

    Class C = Flame spread index 76–200; smoke-developed index 0–450.

    Exception: Materials tested in accordance with Section 803.1.1 and as indicated in Sections 803.1.3 through 803.13.

    803.1.3 Interior wall and ceiling finish materials with different requirements. The materials indicated in Sections 803.2 through 803.13 shall be tested as indicated in the corresponding sections.

    2025 CALIFORNIA BUILDING CODE 8-3

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

    INTERIOR FINISHES

    803.2 Thickness exemption. Materials having a thickness less than 0.036 inch (0.9 mm) applied directly to the surface of walls or ceilings shall not be required to be tested.

    803.3 Heavy timber exemption. Exposed portions of building elements complying with the requirements for buildings of heavy timber construction in Section 602.4 or Section 2304.11 shall not be subject to interior finish requirements except in interior exit stairways, interior exit ramps, and exit passageways.

    803.4 Foam plastics. Foam plastics shall not be used as interior finish except as provided in Section 2603.9. This section shall apply both to exposed foam plastics and to foam plastics used in conjunction with a textile or vinyl facing or cover.

    803.5 Textile wall coverings. Where used as interior wall finish materials, textile wall coverings, including materials having woven or nonwoven, napped, tufted, looped or similar surface and carpet and similar textile materials, shall be tested in the manner intended for use, using the product-mounting system, including adhesive, and shall comply with the requirements of one of the following: Section 803.1.1, 803.5.1 or 803.5.2.

  • CRC § 7.2 Medium relevance — show source text

    7|||||||||||||||||||||||| |Table R702.7 (3)||||†|||||||||||||||||||| |R702.7.2||||||||||||||||||||X|||| |Table_R702.7.3_||||||||||||||||||||X||||

    The state agency does not adopt sections identified with the following symbol: †

    2025 CALIFORNIA RESIDENTIAL CODE 7-1

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    7-2 2025 CALIFORNIA RESIDENTIAL CODE

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

    7 WALL COVERING

    User notes:

    About this chapter: Chapter 7 establishes the various types of materials, materials standards and methods of application permitted as interior and exterior wall coverings. Interior coverings include interior plaster, gypsum board, ceramic tile, wood veneer paneling, hardboard paneling, wood shakes and wood shingles. Exterior wall coverings regulated by this section include aluminum, stone and masonry veneer, wood, hardboard, particleboard, wood structural panel siding, wood shakes and shingles, exterior plaster, steel, vinyl, fiber cement and exterior insulation finish systems. This chapter also contains requirements for the use of vapor retarders for moisture control in walls; wind resistance and water-resistive barriers for exterior wall coverings; and the water-resistive barrier required beneath exterior materials.

    SECTION R701—GENERAL

    R701.1 Application. The provisions of this chapter shall control the design and construction of the interior and exterior wall covering for buildings.

    R701.2 Installation. Products sensitive to adverse weather shall not be installed until adequate weather protection for the installation is provided. Exterior sheathing shall be dry before applying exterior cover.

    SECTION R702—INTERIOR COVERING

    R702.1 General. Interior coverings or wall finishes shall be installed in accordance with this chapter and Tables R702.1(1), R702.1(2), R702.1(3) and R702.3.5. Interior masonry veneer shall comply with the requirements of Section R703.7.1 for support and Section R703.7.4 for anchorage, except an airspace is not required. Interior finishes and materials shall conform to the flame spread and smoke-development requirements of Section R302.9.

    **

    TABLE R702.1(1)—THICKNESS OF PLASTER Col2 Col3
    ** PLASTER BASE** ** FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE**
    (inches)    		 ** FINISHED THICKNESS OF PLASTER FROM FACE OF LATH, MASONRY, CONCRETE**
    (inches)
    ** PLASTER BASE** ** Gypsum Plaster** ** Cement Plaster**
    Expanded metal lath 5/8, minimuma 5/8, minimuma
    Wire lath 5/8, minimuma 3/4, minimum (interior)b
    Wire lath 5/8, minimuma 7/8, minimum (exterior)b
    Gypsum lathg 1/2, minimum 3/4, minimum (interior)b
    Masonry wallsc 1/2, minimum 1/2, minimum
    Monolithic concrete wallsc, d 5/8, maximum 7/8, maximum
    Monolithic concrete ceilingsc, d 3/8,

Frequently asked questions

What test do I ask a manufacturer for to show compliance?

Ask for an ASTM E84 or UL 723 test report showing flame‑spread index and smoke‑developed index, or an NFPA 286 test report that meets the NFPA acceptance criteria per § R302.9.4 .

If a product fails ASTM E84, can it still be used?

Yes — if tested to NFPA 286 and it meets the acceptance criteria (no ceiling spread during 40 kW exposure, no flashover, peak heat release ≤ 800 kW, total smoke ≤ 1,000 m²) per § R302.9.4 file.

Are all trims exempt from flame‑spread rules?

No. Only specific trim types (picture mold, chair rail, baseboard, handrail) and very thin cemented materials (< 1/28 in) under the stated condition are exempt from the flame‑spread index requirement in § R302.9.1 — other trim and decorative materials are controlled elsewhere (see Chapter R8/R804) file.

Do I need a special label on the product?

Manufacturers often mark products with test/class info; if using foam plastics or other special materials, labeling rules in R303 may apply. Verify the product’s test report and labeling meet the applicable section requirements .

Who enforces these requirements on a project?

The local building or fire code official enforces compliance at plan review and inspection; provide test reports and installation details per § R702.1 and § R302.9 file.

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