CWUIC · California Wildland-Urban Interface Code
What test methods govern exterior vent ember resistance?
The CWUIC requires exterior vents to be State Fire Marshal–listed or WUI vents tested to ASTM E2886/E2886M; they must show no flaming in the ember intrusion and integrity (flame intrusion) tests and keep the unexposed-side temperature at or below 662°F (350°C) under § 504.10.1 , with ASTM E2886/E2886M as the referenced test method .
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Exterior ventilation openings must be covered with Wildfire Flame and Ember Resistant vents that are approved and listed by the California State Fire Marshal or are WUI vents tested in accordance with ASTM E2886 / E2886M. The vent assembly must demonstrate (1) no flaming ignition during the Ember Intrusion Test, (2) no flaming ignition during the Integrity Test portion of the Flame Intrusion Test, and (3) a maximum unexposed-side temperature of 662°F (350°C) or less to comply with § 504.10.1 . The referenced test standard is ASTM E2886 / E2886M (Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement) .
The single most important rule: use vents that are State Fire Marshal–listed (or WUI-listed) and have test evidence under ASTM E2886 / E2886M showing no flaming during ember/flame tests and an unexposed-side temperature ≤ 662°F (350°C) (see § 504.10.1) .
Requirements in detail
Controlling code text (plain language)
- Covered openings for attics, eaves, underfloor spaces and other ventilation openings must comply with § 504.10.1 by being fully covered with listed wildfire flame-and-ember-resistant vents or WUI vents tested to ASTM E2886 / E2886M .
- The referenced ASTM standard title in the CWUIC is E2886 / E2886M — "Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement" .
Decision‑relevant dimensions and values
| Item / test criterion | Required value / threshold | Code Reference |
|---|---|---|
| Approved/listed vent | Wildfire Flame and Ember Resistant vents approved and listed by the California State Fire Marshal, or WUI vents tested to ASTM E2886 / E2886M | § 504.10.1 ; ASTM E2886/E2886M |
| Ember Intrusion Test | No flaming ignition of the cotton material during the Ember Intrusion Test | § 504.10.1 |
| Integrity Test (Flame Intrusion) | No flaming ignition during the Integrity Test portion of the Flame Intrusion Test | § 504.10.1 |
| Unexposed-side temperature | Maximum ≤ 662°F (350°C) on the unexposed side of the vent | § 504.10.1 |
| Referenced test method | ASTM E2886 / E2886M (vent ember/flame intrusion test method) | Referenced standards list — E2886/E2886M |
How the standard ties to the code
- The CWUIC requires the vent product to be demonstrated by testing to ASTM E2886 / E2886M to meet the three acceptability items listed above (no flaming during ember and flame tests; temperature limit) — this linkage is explicit in § 504.10.1 .
- ASTM E2886 / E2886M is the industry test method referenced in the CWUIC's referenced standards list for § 504.10.1 . (Note: California amendments to referenced standards elsewhere in the code library may add reporting or procedural clarifications; see the Residential Code references to E2886 amendments for reporting temperature info) .
Exceptions & special cases
- Off-ridge and ridge vents and vents installed on sloped roofs (dormer vents) are governed by § 504.10.2, which additionally requires a mesh with openings not smaller than 1/16 in (1.6 mm) and not larger than 1/8 in (3.2 mm), and that vent and mesh materials be noncombustible and corrosion resistant .
- Location rules (for example, gable-end and dormer vents) appear in § 504.10.3 (gable-end and dormer vents located not less than 10 ft (3048 mm) from lot lines) — consult that section for siting issues .
- The CWUIC requires listed/approved products or E2886 test evidence; simply using mesh size alone (without an approved listing or E2886 test report showing the three acceptance criteria) does not satisfy § 504.10.1 .
Common mistakes
- Mistake: Relying only on a fixed mesh-size label instead of an E2886-tested / State Fire Marshal–listed vent. The code explicitly requires listing or E2886 testing per § 504.10.1 .
- Mistake: Assuming any product with "ember-resistant" marketing meets the code — you must verify the product is listed by the California State Fire Marshal or has a verifiable ASTM E2886 / E2886M test report showing the three acceptance criteria. See § 504.10.1 .
- Mistake: Confusing the temperature threshold or units — the code’s limit is 662°F (350°C) (unexposed side) as the maximum allowed under § 504.10.1 .
- Mistake: Overlooking § 504.10.2 requirements for ridge/off‑ridge vents (mesh size and material requirements) when selecting a roof vent type .
Worked example — applying the rule with numbers
Scenario: You are evaluating a product data sheet and lab report for a soffit vent proposed for an attic.
Product claims: “Ember‑resistant soffit vent — tested to ASTM E2886.” Lab report summary shows:
- Ember Intrusion Test: no flaming of cotton samples.
- Flame Intrusion (Integrity) Test: no flaming observed during the Integrity Test.
- Thermocouple results: maximum unexposed-side temperature recorded = 315°C (599°F).
Compare to the code: § 504.10.1 requires no flaming during Ember Intrusion and Integrity Test, and unexposed-side temp ≤ 350°C (662°F) . The lab results meet both no‑flame criteria and the 315°C < 350°C temperature limit.
Further checks: Confirm the product is listed by the California State Fire Marshal or the manufacturer supplies an approved WUI listing (if not listed, the lab report must be verifiable and match ASTM E2886/E2886M procedures) — the listing requirement is in § 504.10.1 .
Conclusion: If the test report is legitimate and the product is listed (or approved as a WUI vent), the vent would comply with § 504.10.1 given the example numbers .
Related provisions
- § 504.10.1 — Performance requirements for vents (primary controlling provision) .
- § 504.10.2 — Off‑ridge and ridge vents: mesh opening limits, noncombustible and corrosion‑resistant materials .
- § 504.10.3 — Vent locations (example: gable‑end and dormer vents minimum distance from lot lines) .
- Referenced standard: ASTM E2886 / E2886M — Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement (listed in the CWUIC referenced standards) .
- For product listing and State Fire Marshal approvals, consult the State Fire Marshal listing database (the code requires State Fire Marshal listing or WUI listing per § 504.10.1) .
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
CWUIC § 504.9.3 High relevance — show source text
Gaps between doors and door openings_ shall be controlled by one or more of the following methods: 1. Weather-stripping products constructed of materials that which comply with both of the following: 1.1. The tensile strength of the material shall be tested in accordance with ASTM D638 before and after exposure to ASTM G155 for a period of 2,000 hours, and the maximum allowable difference in tensile strength values between exposed and nonexposed samples shall not exceed 10 percent. 1.2. When tested to UL 94, the materials shall have a flammability rating of V-2 or better. 2. Door overlaps onto jambs and headers. 3. Garage door jambs and headers covered with metal flashing.
504.9.3 Conditions of acceptance for ASTM E2707. The ASTM E2707 test shall be conducted on a minimum of three test specimens and meet the conditions of acceptance in Items 1 and 2. If any one of the three tests do not meet the conditions of acceptance, three additional tests shall be performed. All three additional tests must meet the conditions of acceptance. 1. Absence of flame penetration through the wall assembly at any time. 2. Absence of evidence of glowing combustion on the interior surface of the assembly at the end of the 70-minute test.
504.10 Vents. Where provided, ventilation openings for enclosed attics, gable ends, ridge ends, under eaves and cornices, enclosed eave soffit spaces, enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters, underfloor venti
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SPECIAL BUILDING CONSTRUCTION REGULATIONS
lation, foundations and crawl spaces, or any other opening intended to permit ventilation, either in a horizontal or vertical surface, shall be in accordance with Section 504.10.1 or Section 504.10.2 to resist building ignition from the intrusion of burning embers and flame through the ventilation openings.
504.10.1 Performance requirements. Ventilation openings shall be fully covered with Wildfire Flame and Ember Resistant vents approved and listed by the California State Fire Marshal, or WUI vents, tested in accordance with ASTM E2886, to demonstrate compliance with all the following requirements:
- There shall be no flaming ignition of the cotton material during the Ember Intrusion Test.
- There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion Test.
- The maximum temperature of the unexposed side of the vent shall not exceed 662°F (350°C).
504.10.2 Off ridge and ridge vents. Vents that are installed on a sloped roof, such as dormer vents, shall comply with all of the following: 1. Vents shall be covered with a mesh where the dimensions of the mesh therein shall be a minimum of [1] / 16 inch (1.6 mm) and shall not exceed [1] / 8 inch (3.2 mm) in diameter.
2. The vent and mesh material shall be noncombustible.
3. The vent and mesh material shall be corrosion resistant.
CWUIC § 504.10.1 High relevance — show source text
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SPECIAL BUILDING CONSTRUCTION REGULATIONS
lation, foundations and crawl spaces, or any other opening intended to permit ventilation, either in a horizontal or vertical surface, shall be in accordance with Section 504.10.1 or Section 504.10.2 to resist building ignition from the intrusion of burning embers and flame through the ventilation openings.
504.10.1 Performance requirements. Ventilation openings shall be fully covered with Wildfire Flame and Ember Resistant vents approved and listed by the California State Fire Marshal, or WUI vents, tested in accordance with ASTM E2886, to demonstrate compliance with all the following requirements:
- There shall be no flaming ignition of the cotton material during the Ember Intrusion Test.
- There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion Test.
- The maximum temperature of the unexposed side of the vent shall not exceed 662°F (350°C).
504.10.2 Off ridge and ridge vents. Vents that are installed on a sloped roof, such as dormer vents, shall comply with all of the following: 1. Vents shall be covered with a mesh where the dimensions of the mesh therein shall be a minimum of [1] / 16 inch (1.6 mm) and shall not exceed [1] / 8 inch (3.2 mm) in diameter.
2. The vent and mesh material shall be noncombustible.
3. The vent and mesh material shall be corrosion resistant.
504.10.3 Vent locations. Gable-end and dormer vents shall be located not less than 10 feet (3048 mm) from lot lines. Underfloor ventilation openings shall be located as close to grade as practical.
504.11 Accessory buildings and miscellaneous structures. Accessory buildings and miscellaneous structures that have the potential to pose a significant exterior fire exposure hazard during wildfires shall be constructed to conform to the ignition-resistance require- ments of this section.
504.11.1 Applicability . Sections 504.11.2 through 504.11.6 apply to buildings accessory to an applicable building on the same lot, and attached or detached miscellaneous structures that require a building permit, including but not limited to trellises, arbors, patio covers, gazebos and similar structures.
Exceptions: 1. Decks shall comply with the requirements of Section 504.7.3. 2. Awnings and canopies shall comply with the requirements of Section 3105 of the California Building Code.
504.11.2 Miscellaneous structures and accessory buildings within 3 feet. Miscellaneous structures that require a permit, and accessory buildings of any size, when separated from an applicable building on the same lot by a distance of less than 3 feet (914 mm), shall be constructed of noncombustible materials or ignition-resistant building materials as described in Section 503.2.4.
CWUIC § 12-7 High relevance — show source text
504.8
12-7A-3: Horizontal Projection Underside. A fire resistance test standard consisting of a 300 kW intensity direct flame exposure for a 10-minute duration
504.3, 504.7, 504.7.1
12-7A-4: Decking. A two-part test consisting of a heat release rate (Part A) deck assembly combustion test with an under deck exposure of 80 kW intensity direct flame for a 3-minute duration, and a (Part B) sustained deck assembly combustion test consisting of a deck upper surface burning ember exposure with a 12 mph wind for 40 minutes using a 2.2 lb (1kg) burning “Class A” size 12" × 12" × 2.25" (300 mm × 300 mm × 57 mm) roof test brand
504.7.3.2
12-7A-4A: Decking Alternate Method A. A heat release rate deck assembly combustion test with an under deck exposure of 80 kW intensity direct flame for a 3-minute duration
504.7.3.2
State Fire Marshal’s Guidelines for Fire Hydrant Markings Along State Highways and Freeways, May 1988
404.8
UL UL LLC, 333 Pfingsten Road, Northbrook, IL 60062-2096
9—2009: Fire Tests of Window Assemblies—with Revisions through March 2020
504.8
10B—2008: Fire Tests of Door Assemblies—with Revisions through May 2020
504.9
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REFERENCED STANDARDS
10C—2016: Positive Pressure Fire Tests of Door Assemblies—with Revisions through May 2021
504.9
94—2023: Tests for Flammability of Plastic Materials for Parts in Devices and Appliances
504.9.2
263—2011: Fire Tests of Building Construction and Materials—with Revisions through March 2022
501.3, 504.3, 504.3.1, 504.5, 504.7, 504.7.1
723—2018: Test for Surface Burning Characteristics of Building Materials
202, 501.4.1, 503.2.4, 504.7.3.2, 504.7.3.3
790— 2022 : Standard Test Methods for Fire Tests of Roof Coverings
504.2, 504.2.1.2, 504.11.6
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
APPENDIX A – GENERAL REQUIREMENTS
CWUIC § 504.9 High relevance — show source text
E2707—2022: Standard Test Method for Determining Fire Penetration of Exterior Wall Assemblies Using a Direct Flame Impingement Exposure
504.5, 504.9, 504.9.3
E2726/E2726M—2012a(2017): Standard Test Method for Evaluating the Fire Test Response of Deck Structures to Burning Brands
504.7.3.2, 504.7.3.3, 504.7.3.3.2
E2768—11(2018): Standard Test Method for Extended Duration Surface Burning Characteristics of Building Materials (30 min Tunnel Test)
503.2.4
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 7-3
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REFERENCED STANDARDS
E2886/E2886M—20: Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement
504.10.1
E2957—2017 : Standard Test Method for Resistance to Wildfire Penetration of Eaves, Soffits and Other Projections
504.3, 504.7, 504.7.1, 504.7.2
G155—2021: Standard Practice for Operating Xenon Arc Lamp Apparatus for Exposure of Materials
504.9.2
ICC International Code Council, Inc., 200 Massachusetts Avenue, NW, Suite 250, Washington, DC 20001
CBC—2025: California Building Code
1.1.7.3.1, 1.11.2.1.2, 1.11.3.4, 1.11.6 – 1.11.10, 101.3.1, 102.8, 105.1, 105.3, 106.3, 202, 404.10.3, 501.1, 501.3, 503.1, 503.2.2, 503.2.3, 504.2.1.2, 504.3, 504.3.1, 504.5, 504.5.2, 504.6, 504.7, 504.7.3.2, 504.8, 504.11, 504.11.1
CEBC—2025: California Existing Building Code
1.11.3.4, 102.8, 201.3
CFC—2025: California Fire Code
1.11.3.4, 1.11.9, 1.11.10, 102.8, 105.1, 201.3, 202, 402.1.1, 402.1.2, 402.2.1, 402.2.2, 403.2.4, 404.2, 404.4, 404.5, 404.10.3, 606.1, 606.2
CRC—2025: California Residential Code
1.1.7.3.1, 102.8
NFPA National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471
CWUIC § 2303.2 High relevance — show source text
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
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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.
504.4 Gutters and downspouts. Gutters and downspouts shall be constructed of noncombustible material. Gutters shall be provided with an approved means to prevent the accumulation of leaves and debris in the gutter.
504.5 Exterior walls. Exterior walls of buildings or structures shall be constructed with one or more of the following methods, unless they are covered with an exterior wall covering complying with Sections 504.5.2 and 504.5.2.1:
1-hour fire-resistance-rated construction on the exterior side.
Noncombustible materials.
Heavy timber. Assembly of sawn lumber or glue-laminated wood with the smallest minimum nominal dimension of 4 inches (102 mm). Sawn or glue-laminated planks splined, tongue-and-grove or set close together and well spiked. 4. Log wall construction. 5. Wall assemblies that have been tested in accordance with the test procedures for a 10-minute direct flame contact exposure test set forth in ASTM E2707 with the conditions of acceptance shown in Section 504.9.3. 6. Wall assemblies that meet the performance criteria in accordance with the test procedures for a 10-minute direct flame contact exposure test set forth in SFM Standard 12-7A-1. 7. Wall assemblies suitable for exterior fire exposure containing one layer of [5] / 8 -inch (15.9 mm) Type X gypsum sheathing applied behind the exterior wall covering or cladding on the exterior side of the framing. 8. Wall assemblies suitable for exterior fire exposure with a 1-hour fire-resistance rating, rated from the exterior side, as tested in accordance with ASTM E119 or UL 263.
9. Fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code .
CWUIC § 1.3.3.6.1 High relevance — show source text
E2634—2018: Standard Specification for Flat Wall Insulating Concrete Form (ICF) Systems
R404.1.3.3.6.1, R608.4.4
E2634—2018: Standard Specification for Flat Wall Insulating Concrete Form (ICF) Systems
R404.1.3.3.6.1, R608.4.4
E2707—2015: tandard Test Method for Determining Fire Penetration of Exterior Wall Assemblies Using a Direct Flame Impingement Exposure
R337.7.3, R337.7.3.1, R337.8.3
E2726/E2726M—2012a: tandard Test Method for Evaluating the Fire-Test-Response of Deck Structures to Burning Brands
R337.9.3, R337.9.4, R337.9.4.2
E2886/E2886M—2014: Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingent
R337.6.2, R337.6.3
*ASTM E2886, Amended Sections as follows:
Revise Sections 10.1.8.3, 10.1.8.4 and 10.1.8.5 as follows: 10.1.8.3 Report the temperatures of the unexposed temperatures on the unexposed side of the vent during the entire optional Insula- tion Test of the Flame Intrusion.
10.1.8.4 The maximum temperature reached during the test by any one of the unexposed surface thermocouples during the entire optional Insulation Test of the Flame Intrusion Test. 10.1.8.5 The maximum average temperature reached during the test by all of the unexposed surface thermocouples during the entire optional Insulation Test of the Flame Intrusion Test.
E2925—19a: Standard Specification for Manufactured Polymeric Drainage and Ventilation Materials Used to Provide a Rainscreen Function
R703.7.3.2
E2957—2015: Standard Test Method for Resistance to Wildfire Penetration of Eaves, Soffits and Other Projections
R337.7.5, R337.7.6, R337.7.8, R337.7.10
*ASTM E2957, Amended Sections as follows:
Add new Section 12.5 as follows:
12.5 Conditions of Acceptance: Should one of the three replicates fail to meet the Conditions of Acceptance, three additional tests may be run. All of the additional tests must meet the Conditions of Acceptance. 1. Absence of flame penetration of the eaves or horizontal projection assembly at any time. 2. Absence of structural failure of the eaves or horizontal projection subassembly at any time. 3. Absence of sustained combustion of any kind at the conclusion of the 40-minute test.
2025 CALIFORNIA RESIDENTIAL CODE 44-13
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REFERENCED STANDARDS
F844—19: Standard Specification for Washers, Steel, Plain (Flat), Unhardened for General Use
Table R507.2.3
CWUIC § 501.3 High relevance — show source text
501.3, 504.3, 504.3.1, 504.5, 504.7, 504.7.1
E136— 2024a : Standard Test Method for Assessing Combustibility of Materials Using a Vertical Tube Furnace at 750 Degrees C
501.4.1
E1354— 2023 : Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter
503.2.4.3.2, 503.2.4.3.3
E2632—2020: Standard Test Method for Evaluating the Under-Deck Fire Test Response of Deck Materials
504.7.3.2, 504.7.3.3, 504.7.3.3.1, 504.7.3.4
E2652—2022: Standard Test Method for Assessing Combustibility of Materials Using a Tube Furnace with a Cone-shaped Airflow Stabilizer, at 750°C
501.4.1
E2707—2022: Standard Test Method for Determining Fire Penetration of Exterior Wall Assemblies Using a Direct Flame Impingement Exposure
504.5, 504.9, 504.9.3
E2726/E2726M—2012a(2017): Standard Test Method for Evaluating the Fire Test Response of Deck Structures to Burning Brands
504.7.3.2, 504.7.3.3, 504.7.3.3.2
E2768—11(2018): Standard Test Method for Extended Duration Surface Burning Characteristics of Building Materials (30 min Tunnel Test)
503.2.4
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 7-3
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REFERENCED STANDARDS
E2886/E2886M—20: Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingement
504.10.1
E2957—2017 : Standard Test Method for Resistance to Wildfire Penetration of Eaves, Soffits and Other Projections
504.3, 504.7, 504.7.1, 504.7.2
G155—2021: Standard Practice for Operating Xenon Arc Lamp Apparatus for Exposure of Materials
504.9.2
ICC International Code Council, Inc., 200 Massachusetts Avenue, NW, Suite 250, Washington, DC 20001
CBC—2025: California Building Code
CWUIC § 11.3.4 High relevance — show source text
CEBC—2025: California Existing Building Code
1.11.3.4, 102.8, 201.3
CFC—2025: California Fire Code
1.11.3.4, 1.11.9, 1.11.10, 102.8, 105.1, 201.3, 202, 402.1.1, 402.1.2, 402.2.1, 402.2.2, 403.2.4, 404.2, 404.4, 404.5, 404.10.3, 606.1, 606.2
CRC—2025: California Residential Code
1.1.7.3.1, 102.8
NFPA National Fire Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471
252—2022: Standard on Fire Test of Door Assemblies
504.9
257—2022: Standard on Fire Test for Window and Glass Block Assemblies
504.8
CEC—2025: California Electrical Code
201.3
SFM State of California, Department of Forestry and Fire Protection, Office of the State Fire Marshal, P.O. Box 944246, Sacramento, CA 94246-2460
12-7A-1: Exterior Wall Siding and Sheathing. A fire resistance test standard consisting of a 150 kW intensity direct flame exposure for a 10-minute duration
504.5, 504.9
12-7A-2: Exterior Windows. A fire resistance test standard consisting of a 150 kW intensity direct flame exposure for an 8-minute duration
504.8
12-7A-3: Horizontal Projection Underside. A fire resistance test standard consisting of a 300 kW intensity direct flame exposure for a 10-minute duration
504.3, 504.7, 504.7.1
12-7A-4: Decking. A two-part test consisting of a heat release rate (Part A) deck assembly combustion test with an under deck exposure of 80 kW intensity direct flame for a 3-minute duration, and a (Part B) sustained deck assembly combustion test consisting of a deck upper surface burning ember exposure with a 12 mph wind for 40 minutes using a 2.2 lb (1kg) burning “Class A” size 12" × 12" × 2.25" (300 mm × 300 mm × 57 mm) roof test brand
504.7.3.2
12-7A-4A: Decking Alternate Method A. A heat release rate deck assembly combustion test with an under deck exposure of 80 kW intensity direct flame for a 3-minute duration
504.7.3.2
State Fire Marshal’s Guidelines for Fire Hydrant Markings Along State Highways and Freeways, May 1988
404.8
UL UL LLC, 333 Pfingsten Road, Northbrook, IL 60062-2096
9—2009: Fire Tests of Window Assemblies—with Revisions through March 2020
CWUIC § 3.3 High relevance — show source text
R506.3.3
E1886—19: Standard Test Method for Performance of Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Missile(s) and Exposed to Cyclic Pressure Differentials R301.2.1.2, R609.6.1, R609.6.2, Table R703.11.2
E1996—20: Specification for Performance of Exterior Windows, Curtain Walls, Doors, and Impact Protective Systems Impacted by Windborne Debris in Hurricanes
R301.2.1.2, R609.6.1, R609.6.2
E2178—21a: Standard Test Method for Determining Air Leakage Rate and Calculation of Air Permeance of Building Materials
R202
E2273—2018: Standard Test Method for Determining the Drainage Efficiency of Exterior Insulation and Finish Systems (EIFS) Clad Wall Assemblies
R703.9.2
E2556/E2556M—2010(2016): Standard Specification for Vapor Permeable Flexible Sheet Water-resistive Barriers Intended for Mechanical Attachment
R703.2
E2568—2017A: Standard Specification for PB Exterior Insulation and Finish Systems
R703.9.1, R703.9.2
E2570/E2570M—07(2019): Standard Test Methods for Evaluating Water-Resistive Barrier (WRB) Coatings Used under Exterior Insulation and Finish Systems (EIFS) or EIFS with Drainage
R703.9.2
E2632/E2632M—2013e1: Standard Test Method for Evaluating the Under-Deck Fire Test Response of Deck Materials:
R337.9.3, R337.9.4, R337.9.4.1, R337.9.5
E2634—2018: Standard Specification for Flat Wall Insulating Concrete Form (ICF) Systems
R404.1.3.3.6.1, R608.4.4
E2634—2018: Standard Specification for Flat Wall Insulating Concrete Form (ICF) Systems
R404.1.3.3.6.1, R608.4.4
E2707—2015: tandard Test Method for Determining Fire Penetration of Exterior Wall Assemblies Using a Direct Flame Impingement Exposure
R337.7.3, R337.7.3.1, R337.8.3
E2726/E2726M—2012a: tandard Test Method for Evaluating the Fire-Test-Response of Deck Structures to Burning Brands
R337.9.3, R337.9.4, R337.9.4.2
E2886/E2886M—2014: Standard Test Method for Evaluating the Ability of Exterior Vents to Resist the Entry of Embers and Direct Flame Impingent
R337.6.2, R337.6.3
*ASTM E2886, Amended Sections as follows:
Revise Sections 10.1.8.3, 10.1.8.4 and 10.1.8.5 as follows: 10.1.8.3 Report the temperatures of the unexposed temperatures on the unexposed side of the vent during the entire optional Insula- tion Test of the Flame Intrusion.
CWUIC § 1709.5.2 High relevance — show source text
E283/E283M—19: Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen
202
E330/E330M—14(2021): Test Method for Structural Performance of Exterior Windows, Doors, Skylights and Curtain Walls by Uniform Static Air Pressure Difference
1709.5.2, 1709.5.2.1, 1709.5.3.1
E331—2000(2016): Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors and Curtain Walls by Uniform Static Air Pressure Difference
1402.2, 1403.2
E336—20: Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings
1206.2
E492—2009(2016)E1: Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine
1206.3
E580/E580M—22: Standard Practice for Installation of Ceiling Suspension Systems for Acoustical Tile and Lay-in Panels in Areas Subject to Earthquake Ground Motions
1617.12.13, 1617A.1.21
E605/E605M—19: Test Method for Thickness and Density of Sprayed Fire-Resistive Material (SFRM) Applied to Structural Members
1705.15.4.1, 1705.15.4.2, 1705.15.4.5, 1705.15.5
E648—2017A: Standard Test Method for Critical Radiant Flux of Floor-Covering Systems Using a Radiant Heat Energy Source
406.2.4, 424.2, 804.2, 804.3
35-20 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
REFERENCED STANDARDS
E662—17a: Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials
804.4.1, 804.4.2
E681—09(2015): Test Methods for Concentration Limits of Flammability of Chemical Vapors and Gases
202
E736/E736M—19: Test Method for Cohesion/Adhesion of Sprayed Fire-Resistive Materials Applied to Structural Members
704.12.3.2, 1705.15.6
E814—2013A(2017): Standard Test Method for Fire Tests of Penetration Firestop Systems
202, 714.4.1.2, 714.4.2, 714.5.1.2
E970—2017: Standard Test Method for Critical Radiant Flux of Exposed Attic Floor Insulation Using a Radiant Heat Energy Source
720.3.1
E1007—21: Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission through Floor-Ceiling Assemblies and Associated Support Structures
1206.3
E1300—2016: Practice for Determining Load Resistance of Glass in Buildings
2404.1, 2404.2, 2404.3.1, 2404.3.2, 2404.3.3, 2404.3.4, 2404.3.5
CWUIC § 304.8 Medium relevance — show source text
The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave overhang if fireblocking is provided from the wall top plate to the underside
of the roof sheathing.
b. The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the rake overhang where vent openings that communicate with the attic are not
installed in the overhang or gable wall.|For SI: 1 foot = 304.8 mm.
NA = Not Applicable.
a. The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave overhang if fireblocking is provided from the wall top plate to the underside
of the roof sheathing.
b. The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the rake overhang where vent openings that communicate with the attic are not
installed in the overhang or gable wall.|TABLE R302.1(2)—EXTERIOR WALLS—DWELLINGS, TOWNHOUSES AND ACCESSORY BUILDINGS
WITH AUTOMATIC RESIDENTIAL FIRE SPRINKLER PROTECTIONCol2 Col3 Col4 ** EXTERIOR WALL ELEMENT** ** EXTERIOR WALL ELEMENT** ** MINIMUM FIRE-RESISTANCE RATING** ** MINIMUM FIRE**
SEPARATION
DISTANCEWalls Fire-resistance rated 1 hour—tested in accordance with ASTM E119, UL 263 or Section 703.2.2 of
the_California Building Code_ with exposure from the outside0 feet Walls Not fire-resistance rated 0 hours 3 feeta Projections Not allowed NA < 2 feet Projections Fire-resistance rated 1 hour on the underside, or heavy timber, or fire-retardant-treated woodb, c 2 feeta Projections Not fire-resistance rated 0 hours 3 feet Openings in
wallsNot allowed NA < 3 feet Openings in
wallsUnlimited 0 hours 3 feeta Penetrations All Comply with Section R302.4 < 3 feet Penetrations All None required 3 feeta For SI: 1 foot = 304.8 mm.
NA = Not Applicable.
a. For residential subdivisions where all dwellings and townhouses are equipped throughout with an automatic sprinkler system installed in accordance with Section_R309_, the fire
separation distance for exterior walls not fire-resistance rated and for fire-resistance-rated projections shall be permitted to be reduced to 0 feet, and unlimited unprotected
openings and penetrations shall be permitted, where the adjoining lot provides an open setback yard that is 6 feet or more in width on the opposite side of the property line.
b. The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave overhang if fireblocking is provided from the wall top plate to the underside
of the roof sheathing.
c. The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the rake overhang where vent openings that communicate with the attic are not
installed in the overhang or gable wall.For SI: 1 foot = 304.8 mm.
NA = Not Applicable.
a.California Wildland-Urban Interface Code Medium relevance — show source text
does not meet the
criteria for Category 1 or Category 2.| |Aerosol|Aerosol|Level 2|Those with a total chemical heat of combustion that is
less than or equal to 8,600 Btu/lb (20 kJ/g).|H223, Category 2; Flammable aerosol. Pressurized
container: May burst if heated:
1.
Any aerosol that dispenses a spray that, based
on the results of the ignition distance test, does
not meet the criteria for Category 1, and which
has:
a.
A heat of combustion of ≥ 20 kJ/g.
b.
A heat of combustion of < 20 kJ/g along
with an ignition distance of ≥ 15 cm; or
c.
A heat of combustion of < 20 kJ/g and an
ignition distance of < 15 cm along with
either, in the enclosed space ignition test
a time:
i. A time equivalent of ≤ 300 s/m3; or
ii. A deflagration density of ≤ 300
g/m3; or
2.
Any aerosol that dispenses a foam that, based
on the results of the aerosol foam flammability
test, does not meet the criteria for Category 1,
and which has a flame height of ≥ 4 cm and a
flame duration of ≥ 2 s.| |Aerosol|Aerosol|Level 3|Those with a total chemical heat of combustion that is
greater than 13,000 Btu/lb (30 kJ/g).|H222, Category 1; Extremely flammable aerosol. Pres-
surized container: May burst if heated:
1.
Any aerosol that contains ≥ 85% flammable
components (by mass) and has a heat of
combustion of ≥ 30 kJ/g.
2.
Any aerosol that dispenses a spray that, in the
ignition distance test, has an ignition distance
of ≥ 75 cm.
3.
Any aerosol that dispenses a foam that, in the
foam flammability test, has:
a.
A flame height of ≥ 20 cm and a flame
duration of ≥ 2 s.
b.
A flame height of ≥ 4 cm and a flame
duration of ≥ 7 s.| |Combustible
liquid|Combustible
liquid|—|A liquid having a closed cup flash point at or above
100°F (38°C).
Frequently asked questions
Can I meet § 504.10.1 by using a metal mesh with 1/8‑inch openings?
No. For compliance you must use vents that are listed by the California State Fire Marshal or are WUI vents tested to ASTM E2886 / E2886M and demonstrate the acceptance criteria in § 504.10.1. Mesh size alone does not substitute for the required testing/listing; note also that § 504.10.2 separately sets mesh size and material rules for ridge/off‑ridge vents .
What exactly must an E2886 test report show to satisfy the code?
The CWUIC requires that E2886 testing demonstrate no flaming ignition during the Ember Intrusion Test, no flaming ignition during the Integrity Test portion of the Flame Intrusion Test, and that the unexposed‑side temperature does not exceed 662°F (350°C) as stated in § 504.10.1 .
Are E2886 and E2886M different requirements?
E2886M is the metric companion standard to E2886; CWUIC references E2886/E2886M as the test method for vents in the referenced standards list and requires testing to that standard for § 504.10.1 compliance .
Where do I verify a vent is “listed” by the California State Fire Marshal?
The code text requires a State Fire Marshal listing or a WUI product listing as the compliance path in § 504.10.1. Verify the product on the State Fire Marshal’s listing database and confirm the listing references ASTM E2886/E2886M test evidence as applicable .
If a vent passes E2886 but its unexposed side reaches 360°C, is it acceptable?
No. § 504.10.1 sets the unexposed‑side maximum at 350°C (662°F). A maximum of 360°C would exceed the code limit and therefore would not comply under that acceptance criterion .
More in California Wildland-Urban Interface Code
- Administration and Definitions
- Board of Appeals, Administration & Enforcement (permits, code official duties, appeals process)
- Wildland‑Urban Interface Area Designation & Mapping
- Fire Service Access & Water Supply (fire apparatus roads, driveways, hydrants, draft sites, standby power)
- Wildland‑Urban Interface Area Requirements (access, water, premises identification, key boxes)
- Referenced Standards & Test Methods
- Special Building Construction Regulations (ignition‑resistant construction, roof/vent/assembly requirements)
- Appendices and Model Ordinances (vegetation plans, severity‑zone adoption, home‑hardening guidance)
- Fire Protection Requirements (fire protection plans, systems, safety element provisions)
- Referenced California Documents & Matrix (CCR/Title 14 & 19 cross‑references, statutory references)
- Vegetation Management & Defensible Space (vegetation plans, maintenance, fire‑smart characteristics)
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