CWUIC · California Wildland-Urban Interface Code
What are the test requirements for windows and window assemblies under wildfire exposure?
Windows in WUI areas must either be one of the glazing types allowed in **§ 504.8** or be demonstrated (by a test report) to survive a **150 kW** direct flame impingement for **8 minutes** with no flame penetration or structural failure per **SFM 12‑7A‑2/12‑7A‑2.8**; any flame penetration or structural failure during the test is a fail.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Windows, window walls and glazed doors used in Wildland‑Urban Interface areas must either meet specified wildfire exposure performance or be constructed of accepted glazing types. The wildfire performance path is the State Fire Marshal test SFM Standard 12‑7A‑2, which requires a window/window assembly to withstand 8 minutes of direct flame exposure without flame penetration or structural failure — see § 12‑7A‑2.8. For allowable glazing types the CWUIC lists options in § 504.8. § 12‑7A‑2 and § 12‑7A‑2.8 set the detailed test setup and pass/fail criteria.
The single most important rule: a window/window assembly must resist 8 minutes of direct flame impingement without flame penetration through the glazing or frame, or structural failure of the glazing or frame. § 12‑7A‑2.8
Requirements in detail
Controlling sections (first‑mention)
- § 504.8 — Acceptable glazing constructions and alternative performance compliance paths (CWUIC glazing rules).
- § 12‑7A‑2 — SFM Standard describing the test apparatus, specimen construction, burner, and positioning.
- § 12‑7A‑2.8 — Conditions of acceptance: 8 minutes direct flame exposure; any flame penetration or structural failure = failure.
Decision‑relevant dimensions and values (quick reference table)
| Dimension / value (bolded on first mention) | What it controls / why it matters | Code reference |
|---|---|---|
| Duration — 8 minutes | Specimen must withstand continuous direct flame for 8 minutes to pass. | § 12‑7A‑2.8 |
| Burner heat output — 150 ± 4 kW | Prescribed net heat release rate for the flame source used to impinge on the wall/window. | § 12‑7A‑2.5 |
| Burner geometry — 4 × 39 in (100 × 1000 mm) diffusion burner | Defines the flame shape and coverage used in the test. | § 12‑7A‑2.5 |
| Window width limit — 3 ft (900 mm) | Standard test fixture limits the tested window width; larger windows require a larger test module. | § 12‑7A‑2.6 |
| Burner to bottom of window — 8 in (200 mm) | Vertical placement that determines flame impingement on sill/assembly. | § 12‑7A‑2.6 |
| Burner vertical position — top of burner 12 in (300 mm) from floor of test assembly | Ensures consistent flame alignment in the module. | § 12‑7A‑2.5 |
| Allowed glazing options | Multilayered glazed with at least one tempered pane; glass block; glazing with ≥20‑minute fire‑protection rating (NFPA 257 or UL 9) or glazing meeting SFM 12‑7A‑2 performance. | § 504.8 |
| Pass/fail trigger | Any flame penetration through frame or pane OR structural failure at any time during the test = failure. | § 12‑7A‑2.8 |
Test apparatus & specimen setup (high‑level)
- The test uses a Wall Assembly Test Module (pre‑fabricated 4 × 8 ft wall with noncombustible sides and a simulated soffit) into which the window assembly is installed and sealed to prevent edge effects. § 12‑7A‑2.5
- Burner verification: run the burner at 150 kW for a verification run (typically 3 minutes) before specimens are tested to confirm output. § 12‑7A‑2.7
- The burner is centered and placed so the flame covers the full width of the sill; test continues until flame‑through occurs or until test time is reached. § 12‑7A‑2.7
Report and replicates
- Test reports must describe the window unit (frame types, claddings, panes), installation details, and timing/location of glass breakage, flame‑through or frame failure. § 12‑7A‑2.7
- The referenced SFM standard describes replicates and reporting requirements; follow those documentation items when claiming compliance. § 12‑7A‑2.5–2.7
Exceptions & special cases
- CWUIC permits alternative glazing types that bypass the SFM 12‑7A‑2 performance route: multilayered glazing with at least one pane of tempered glass, glass block, or glazing with a 20‑minute fire protection rating tested to NFPA 257 or UL 9 (exempt from the hose‑stream test). See § 504.8.
- The SFM test fixture limits window width to 3 ft (900 mm); larger windows can be tested if the test lab expands the rear wall of the Wall Assembly Test Module to accommodate them — check § 12‑7A‑2.6 before assuming a test is invalid for size.
- If the specimen shows no penetration during the flame exposure, the test may include an additional observation period for sustained combustion as described in the referenced procedures — see the conduct and reporting provisions of § 12‑7A‑2.7.
Common mistakes
- Confusing the 8‑minute SFM wildfire direct flame test with a 20‑minute fire‑protection rating test (NFPA 257/UL 9). The 8‑minute SFM pass/fail is a wildfire direct‑flame performance criterion; 20‑minute ratings are an alternate listed glazing option in § 504.8.
- Assuming any labeled “fire‑rated” glazing automatically satisfies SFM 12‑7A‑2 performance — list your basis: either the glazing type permitted under § 504.8 or a test report showing conformance to 12‑7A‑2.
- Overlooking installation details in the test assembly (trim, gypsum mounting strips, caulk, sealing of edges). The SFM standard prescribes minimum wall assembly components and sealing methods in the test so the result reflects installed performance. § 12‑7A‑2.6 and § 12‑7A‑2.7.
Worked example — concrete scenario with numbers
Scenario: You have a 2.5 ft (762 mm) wide replacement window with an aluminum frame and double glazing; you want to know whether the assembly meets CWUIC wildfire requirements.
Step‑by‑step:
- The test path: either show the glazing meets one of the allowed constructions in § 504.8 (e.g., multilayered with tempered pane, glass block, or 20‑minute rated glazing) — OR — obtain a test report showing the installed assembly was tested to SFM 12‑7A‑2 and withstood 150 ± 4 kW burner exposure for 8 minutes without flame penetration or structural failure. § 12‑7A‑2.5; § 12‑7A‑2.8
- Test geometry: with a 2.5 ft width you are within the standard fixture limit (≤ 3 ft (900 mm)) so a standard test module can be used; the burner is centered and set at 150 kW, top of burner 12 in from the test‑floor and 8 in below the window bottom. § 12‑7A‑2.6; § 12‑7A‑2.5
- Acceptance: if the lab report documents that during the 8‑minute flame exposure there was no flame penetration of the glazing or frame and no structural failure of the frame or glazing, the assembly passes per § 12‑7A‑2.8. Any flame penetration or structural failure at any time = fail.
Practical implication: if your unit’s test report documents the 8‑minute pass, or the glazing type matches § 504.8 options, you can document compliance for CWUIC purposes.
Related provisions
- § 504.8 — Exterior glazing allowed constructions and alternatives (glazing types and 20‑minute fire‑protection rating option).
- § 12‑7A‑2 — SFM Standard: Exterior Windows (test apparatus, burner, specimen).
- § 12‑7A‑2.8 — Conditions of acceptance (8‑minute duration; flame penetration/structural failure criterion).
- § 504.9 — Exterior doors (glazed openings within doors must comply with § 504.8).
- § 501.3 — Fire‑resistance rating determination procedures referenced elsewhere in Chapter 5.
- § 12‑7A‑3 — Horizontal projection (eaves/soffit) test standard — related because window areas near eaves interact with other wildfire exposure requirements.
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
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 § 12-7 High relevance — show source text
Note the time elapsed and location of penetration if it occurs. 4. Report. Report a description of the window unit, including the types of frames, cladding and panes being tested and details of the installation. Record when and how the glass breaks or flame-through occurs in the framing materials or sash, and/or
2025 CALIFORNIA REFERENCED STANDARDS CODE 41
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MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE
if the framing material deforms or otherwise suffers a loss of integrity such that the glass cannot be held in place, and a record of the time at which any of these events occur.
12-7A-2.8 Conditions of Acceptance.
- Duration of direct flame exposure. To pass this test standard, the window and window assembly shall withstand 8 minutes of direct flame exposure with the absence of flame penetration through the window frame or pane, or structural failure of the window frame or pane.
- Flame penetration or structural failure. Flame penetration or structural failure of the flame or pane anytime during the test constitutes failure of this test standard.
FIGURE 1 — SCHEMATIC OF THE WALL ASSEMBLY Test Module used for evaluating the fire performance of a window.
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MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE
HORIZONTAL PROJECTION UNDERSIDE
SFM STANDARD 12-7A-3
12-7A-3.1 Application. The minimum design, construction and performance standards set forth herein for the exposed underside of horizontal projections such as the horizontal soffits of roof eaves, floor projections and exposed underfloor areas are those deemed necessary to establish conformance to the provisions of these regulations. Materials and assemblies that meet the performance criteria of this standard are acceptable for use as defined in the California Building Standards Code.
12-7A-3.2 Scope. This standard evaluates the fire-resistive performance of horizontal projection assemblies including the horizontal soffits of roof eaves, floor projections and exposed underfloor areas when subjected to direct flame exposure to the underside of a horizontal projection.
12-7A-3.3 Referenced documents.
ASTM D4442, Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials.
ASTM D4444, Test Methods for Use and Calibration of Hand-Held Moisture Meters.
California Building Code, Chapter 7A.
12-7A-3.4 Definitions.
- Eaves. A projecting edge of a roof that extends beyond the supporting wall as in CBC 702A “Roof Eave” or similar horizontal projection assembly.
- Soffit. The enclosed underside of any exterior overhanging section of a roof eave or similar horizontal projection assembly (see CBC 702A “Roof Eave Soffit”).
12-7A-3.5 Equipment.
- Burner. A 12 by 12-inch (300 by 300 mm) diffusion burner shall be used. Natural gas, methane or propane shall be supplied to the burner through a metered control system.
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 § 2.2. High relevance — show source text
2.2. Gypsum board for mounting around the window once it is installed; 2.3. Pieces of gypsum cut into narrow strips for use as trim around the window; 2.4. Caulk to be used as per the window manufacturer's instructions. 3. Wall assembly. A noncombustible wall shall be used with a manufacturer or code-specified opening for the particular window. Install window in framed rough opening following manufacturer guidelines. Apply manufacturer-recommended caulk to nailing flange prior to installation. Use narrow strips of gypsum board as trim around window, covering the nail flange of the window. Any type of framing material may be tested. 3.1. Fit the window test assembly into the rear wall of the Wall Assembly Test Module, sealing all edges, including the soffit-to-wall joint. Ceramic wool or comparable material shall be used for sealing.
12-7A-2.7 Conduct of tests.
Burner output verification. Without the window in place, set the burner for 150 kW output. Conduct a verification run of 3 minutes to assure the heat release rate, and then turn off the burner.
Test. Place the burner against the wall assembly at the center. Ignite the burner at the 150 kW output and control during the test for constant and uniform output. Optional radiometers can be placed behind the Wall Assembly Test Module to measure heat flux through the window glass.
Duration and observations. The test shall be continued until flame-through occurs at the window. Flame-through can occur at the glass (glazing) and/or in the frame. At this point, the burner shall be extinguished and the assembly monitored for sustained combustion. Note the time elapsed and location of penetration if it occurs.
Report. Report a description of the window unit, including the types of frames, cladding and panes being tested and details of the installation. Record when and how the glass breaks or flame-through occurs in the framing materials or sash, and/or
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if the framing material deforms or otherwise suffers a loss of integrity such that the glass cannot be held in place, and a record of the time at which any of these events occur.
12-7A-2.8 Conditions of Acceptance.
- Duration of direct flame exposure. To pass this test standard, the window and window assembly shall withstand 8 minutes of direct flame exposure with the absence of flame penetration through the window frame or pane, or structural failure of the window frame or pane.
- Flame penetration or structural failure. Flame penetration or structural failure of the flame or pane anytime during the test constitutes failure of this test standard.
FIGURE 1 — SCHEMATIC OF THE WALL ASSEMBLY Test Module used for evaluating the fire performance of a window.
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HORIZONTAL PROJECTION UNDERSIDE
SFM STANDARD 12-7A-3
CWUIC § 12-7 High relevance — show source text
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MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE
EXTERIOR WINDOWS
SFM STANDARD 12-7A-2
12-7A-2.1 Application. Exterior window assemblies that meet the performance criteria of this standard are acceptable for use as defined in the California Building Standards Code.
12-7A-2.2 Scope. This standard evaluates the performance of exterior windows used in structures when exposed to direct flames.
12-7A-2.3 Referenced documents.
- AAMA (for definitions) Training Manual, Residential & Light Commercial Window and Door Installation Training and Registration Program.
- CAWM 400-95, Standard Practice for Installation of Windows with Integral Mounting Flange in Wood Frame Construction.
12-7A-2.4 Definitions.
Frame (Jambs). This usually consists of two vertical members (side jambs) and two horizontal members (head and sill) that hold the sash. Frames and sash are typically made of steel, aluminum, vinyl, fiberglass, wood or a combination of these materials.
Glazing. The glass in a window. It may include layers of plastic as well as glass.
Sash. The fixed or movable parts of the window in which the panes of glass are set.
12-7A-2.5 Test apparatus.
- Wall assembly test module. The module is designed to permit rapid installation and removal of window/wall assemblies, and is designed to prevent edge penetration of fire at the margins. It includes two noncombustible side walls attached to a wall frame assembly, and a simulated soffit that is also noncombustible. The assembly permits a prefabricated 4 × 8 ft (1.2 × 2.4 m) wall section containing the test window to be inserted from the rear and sealed in such a way that the edges are protected from fire (see Figure 1).
- Burner. A 4 × 39 inch (100 × 1000 mm) diffusion burner shall be used. Natural gas, methane or propane shall be supplied to the burner through a metered control system. The gas supply to the burner shall produce a net heat output of 150 ± 4 kW throughout the flame exposure. Burner output can be determined from HRR or calculated from the gas flow rate, temperature and pressure.
- Burner location. The burner shall be positioned so that it is centered relative to the width of the wall assembly and against the wall. The distance from the floor to the top of the burner shall be 12 inches (300 mm).
12-7A-2.6 Test assembly.
- Window. The window width cannot exceed 3 feet (900 mm) due to the limitations of the test fixture. The burner’s flame shall cover the full width of the window sill. The distance from top of the burner to bottom of window will be 8 inches (200 mm).
CWUIC § 504.8 High relevance — show source text
504.8 Exterior glazing. Exterior windows, window walls and glazed doors, windows within exterior doors, and skylights shall be constructed of any of the following: 1. Multilayered glazed panels with at least one pane of tempered glass complying with Section 2406 of the California Building Code.
2. Glass block.
3. Glazing with a fire-protection rating of not less than 20 minutes when tested according to NFPA 257 or UL 9, and shall be exempt from the hose stream test. 4. Glazing meeting the performance requirements of SFM Standard 12-7A-2.
504.8.1 Structural glass veneer. The wall assembly behind structural glass veneer shall comply with Section 504.5.
504.8.2 Operable skylights. Operable skylights shall be protected by a noncombustible mesh screen and the dimensions of the openings in the screen shall not exceed [1] / 8 inch (3.2 mm).
504.9 Exterior doors. Exterior doors shall be constructed in accordance with any of the following:
1. Noncombustible construction .
2. Solid-core wood not less than 1 [3] / 4 inches thick (44 mm) . 3. The exterior door shall be constructed of solid core wood that complies with the following requirements: 3.1. Stiles and rails shall not be less than 1 3/8 inches (35 mm) thick. 3.2. Raised panels shall not be less than 11/4 inches (32 mm) thick, except for the exterior perimeter of the raised panel that shall be permitted to taper to a tongue not less than 3/8 inch (10 mm) thick. 4. Have a fire protection rating of not less than 20 minutes when tested according to NFPA 252, UL 10B or UL 10C . 5. The exterior surface or cladding meeting the performance requirements of Section 504.9.3 when tested in accordance with ASTM E2707.
6. The exterior surface or cladding shall be tested to meet the performance requirements of SFM Standard 12-7A-1.
Windows within doors and glazed doors shall be in accordance with Section 504.8.
504.9.1 Garage doors. Automatic garage door openers for vehicle doors serving a residential building shall be equipped with a battery backup function.
504.9.2 Garage door perimeter gap. Exterior garage doors shall resist the intrusion of embers by preventing gaps between doors and door openings, at the bottom, sides and tops of doors, from exceeding [1] / 8 _inch (3.2 mm).
CWUIC § 12-7 High relevance — show source text
12-7A-2.5 Test apparatus.
- Wall assembly test module. The module is designed to permit rapid installation and removal of window/wall assemblies, and is designed to prevent edge penetration of fire at the margins. It includes two noncombustible side walls attached to a wall frame assembly, and a simulated soffit that is also noncombustible. The assembly permits a prefabricated 4 × 8 ft (1.2 × 2.4 m) wall section containing the test window to be inserted from the rear and sealed in such a way that the edges are protected from fire (see Figure 1).
- Burner. A 4 × 39 inch (100 × 1000 mm) diffusion burner shall be used. Natural gas, methane or propane shall be supplied to the burner through a metered control system. The gas supply to the burner shall produce a net heat output of 150 ± 4 kW throughout the flame exposure. Burner output can be determined from HRR or calculated from the gas flow rate, temperature and pressure.
- Burner location. The burner shall be positioned so that it is centered relative to the width of the wall assembly and against the wall. The distance from the floor to the top of the burner shall be 12 inches (300 mm).
12-7A-2.6 Test assembly.
- Window. The window width cannot exceed 3 feet (900 mm) due to the limitations of the test fixture. The burner’s flame shall cover the full width of the window sill. The distance from top of the burner to bottom of window will be 8 inches (200 mm).
Note: Larger windows may be tested by expanding the size of the rear wall of the Wall Assembly Test Module. 2. Materials. In the absence of the window manufacturer's specifications, the wall assembly shall include the following minimum components: 2.1. 2 by 4 inch studs spaced 16 inches (410 mm) on center, framed out to incorporate a rough opening sized to receive the test window such that the window is centered relative to the width of the wall;
2.2. Gypsum board for mounting around the window once it is installed; 2.3. Pieces of gypsum cut into narrow strips for use as trim around the window; 2.4. Caulk to be used as per the window manufacturer's instructions. 3. Wall assembly. A noncombustible wall shall be used with a manufacturer or code-specified opening for the particular window. Install window in framed rough opening following manufacturer guidelines. Apply manufacturer-recommended caulk to nailing flange prior to installation. Use narrow strips of gypsum board as trim around window, covering the nail flange of the window. Any type of framing material may be tested. 3.1. Fit the window test assembly into the rear wall of the Wall Assembly Test Module, sealing all edges, including the soffit-to-wall joint. Ceramic wool or comparable material shall be used for sealing.
12-7A-2.7 Conduct of tests.
Burner output verification. Without the window in place, set the burner for 150 kW output. Conduct a verification run of 3 minutes to assure the heat release rate, and then turn off the burner.
Test. Place the burner against the wall assembly at the center. Ignite the burner at the 150 kW output and control during the test for constant and uniform output. Optional radiometers can be placed behind the Wall Assembly Test Module to measure heat flux through the window glass.
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
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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 § 12-7 High relevance — show source text
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MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE
12-7A-1.10 Report. The report shall include the following:
Name and address of the testing laboratory.
Name and address of test sponsor.
Description of the test specimen including construction details of the wall system, including details of individual components (such as type, thickness and installation method of any sheathing) and the manufacturer’s installation details and limitations as applicable.
Number of specimens tested.
Description of weathering, as applicable.
Moisture content of hygroscopic elements of wall system construction at the time of testing.
Details of the burner verification, including heat supply rate.
Date of test, test identification number and date of report.
The test results shall include:
9.1. A notation of the time and location of sustained flaming on the unexposed side of the test specimen during the test, along with the sequence number of the test specimen. 9.2. A determination of the presence of glow on the unexposed side of the test specimen at the end of the 60-minute observation period. 9.3. Observations of the burning characteristics of the exposed surface of the test wall during and after the flame
exposure.
12-7A-1.11 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.
- Absence of flame penetration through the wall assembly at any time.
- Absence of evidence of glowing combustion on the interior surface of the assembly at the end of the 70-minute test.
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MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE
EXTERIOR WINDOWS
SFM STANDARD 12-7A-2
12-7A-2.1 Application. Exterior window assemblies that meet the performance criteria of this standard are acceptable for use as defined in the California Building Standards Code.
12-7A-2.2 Scope. This standard evaluates the performance of exterior windows used in structures when exposed to direct flames.
12-7A-2.3 Referenced documents.
- AAMA (for definitions) Training Manual, Residential & Light Commercial Window and Door Installation Training and Registration Program.
- CAWM 400-95, Standard Practice for Installation of Windows with Integral Mounting Flange in Wood Frame Construction.
12-7A-2.4 Definitions.
Frame (Jambs). This usually consists of two vertical members (side jambs) and two horizontal members (head and sill) that hold the sash. Frames and sash are typically made of steel, aluminum, vinyl, fiberglass, wood or a combination of these materials.
Glazing. The glass in a window. It may include layers of plastic as well as glass.
Sash. The fixed or movable parts of the window in which the panes of glass are set.
12-7A-2.5 Test apparatus.
- Wall assembly test module. The module is designed to permit rapid installation and removal of window/wall assemblies, and is designed to prevent edge penetration of fire at the margins.
CWUIC § 12-7 High relevance — show source text
- When tested as follows, flames shall not reach the top edge of the specimen. The test shall be conducted in a draft free area, on a specimen of the material 12 inches by 12 inches (305 mm by 305 mm) suspended at a 45-degree angle from the horizontal with the upper and lower edges in a horizontal plane. The test flame shall be 3 inches (76 mm) long from a Bunsen burner of approximately [1] / 2 -inch (13 mm) inside diameter with the air supply completely shut off. The burner shall be positioned so that its top is 1 inch (25 mm) vertically below a point on the lower surface of the test specimen, 1 inch (25 mm) up from its lower horizontal edge and midway between the inclined edges. The exposure to the test flame and the duration of test shall be for a period of 2 minutes.
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36 2025 CALIFORNIA REFERENCED STANDARDS CODE
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12-7A MATERIALS AND CONSTRUCTION METHODS
FOR EXTERIOR WILDFIRE EXPOSURE
EXTERIOR WALL SIDING AND SHEATHING
SFM STANDARD 12-7A-1
12-7A-1.1 Application. The minimum design, construction and performance standards set forth herein for exterior wall siding and sheathing are those deemed necessary to establish conformance to the provisions of these regulations. Materials and assemblies that meet the performance criteria of this standard are acceptable for use as defined in California Building Standards Code.
12-7A-1.2 Scope. This standard evaluates the performance of exterior walls of structures when exposed to direct flames.
12-7A-1.3 Referenced documents.
ASTM E2257, Test Method for Room Fire Test of Wall and Ceiling Materials and Assemblies.
ASTM D4442, Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials.
ASTM D4444, Test Methods for Use and Calibration of Hand-Held Moisture Meters.
California Building Code, Chapter 7A.
12-7A-1.4 Definitions.
- Siding (cladding). Any material that constitutes the exposed exterior covering of an exterior wall and is applied over sheathing or is directly attached to the wall structural system.
- Sheathing. The material placed on an exterior wall beneath cladding or siding and is directly attached to the wall structural system.
12-7A-1.5 Summary of test method.
- Direct flame exposure. This test method provides for the direct flame exposure of a wall specimen to a flame source centered at the base of a 4-foot by 8-foot (1220 mm by 2440 mm) test assembly.
- Gas burner. The method employs a gas burner to produce a diffusion flame in contact with the test wall assembly.
- Heat output. The gas burner produces a prescribed net rate of heat output of 8535 Btu/min (150 kW) for a period of 10 minutes, after which the flame exposure is terminated.
- Resistance to fire penetration. The test method measures the ability of the wall system to resist fire penetration from the exterior to the unexposed side of the test assembly under the conditions of exposure.
CWUIC § 716.3.2.1.3 High relevance — show source text
716.3.2.1.3 Where [1] / 3 -hour-fire-protection window assemblies permitted. Fire-protection-rated glazing shall be permitted in window assemblies tested to NFPA 257 or UL 9 in fire partitions requiring [1] / 3 -hour opening protection in accordance with Table 716.1(3).
716.3.3 Fire window frames. Fire window frames installed with a fire window assembly shall meet the fire-protection rating indicated in Table 716.1(3).
716.3.3.1 Window mullions. Metal mullions that exceed a nominal height of 12 feet (3658 mm) shall be protected with materials to afford the same fire-resistance rating as required for the wall construction in which the protective is located.
716.3.4 Fire-protection-rated glazing. Glazing in fire window assemblies shall be fire protection rated in accordance with this section and Table 716.1(3). Fire-protection-rated glazing in fire window assemblies shall be tested in accordance with and shall meet the acceptance criteria of NFPA 257 or UL 9. Openings in nonfire-resistance-rated exterior wall assemblies that require protection in accordance with Section 705.3, 705.9, 705.9.5 or 705.9.6 shall have a fire protection rating of not less than [3] / 4 hour. Fire-protection-rated glazing in [1] / 2 -hour fire-resistance-rated partitions is permitted to have a 20-minute fire protection rating.
716.3.4.1 Glass and glazing. Glazing in fire window assemblies shall be fire-protection-rated glazing installed in accordance with and complying with the size limitations set forth in NFPA 80.
716.3.5 Labeled protective assemblies. Glazing in fire window assemblies shall be labeled by an approved agency. The labels shall comply with NFPA 80 and Section 716.3.5.2.
716.3.5.1 Fire window frames. Fire window frames shall be approved for the intended application.
716.3.5.2 Labeling requirements. Fire-protection-rated glazing shall bear a label or other identification showing the name of the manufacturer, the test standard and information required in Section 716.1.2.2.2 and Table 716.1(3) that shall be issued by an approved agency and permanently identified on the glazing.
716.3.6 Installation. Fire window assemblies shall be installed in accordance with the provisions of this section.
716.3.6.1 Closure. Fire-protection-rated glazing shall be in the fixed position or be automatic-closing and shall be installed in labeled frames.
716.4 Fire protective curtain assembly. Approved fire protective curtain assemblies shall be constructed of any materials or assembly of component materials tested without hose stream in accordance with UL 10D, and shall comply with the Sections 716.4.1 through 716.4.3.
716.4.1 Label. Fire protective curtain assemblies used as opening protectives in fire-rated walls and smoke partitions shall be labeled in accordance with Section 716.2.9.
716.4.2 Smoke and draft control. Fire protective curtain assemblies used to protect openings where smoke and draft control assemblies are required shall comply with Section 716.2.1.4.
716.4.3 Installation. Fire protective curtain assemblies shall be installed in accordance with NFPA 80.
SECTION 717—DUCTS AND AIR TRANSFER OPENINGS
CWUIC § 0.5 High relevance — show source text
** The horizontal airflow, measured at a horizontal distance of 20 inches (0.5 m) from the edge of the wall assembly, shall not exceed 1.64 ft/s (0.5 m/s). 3. Placement of test frame. Prior to testing, and without the test specimen in place, position the frame assembly under the exhaust hood and set the gas burner for the prescribed level of output. 4. Placement of specimen. Once the burner output is verified, position the specimen holder assembly at the desired test location under the collection hood.
- Test specimen. Insert the test specimen into the frame assembly, sealing all edges with ceramic wool.
- Ignition. Simultaneously ignite the gas burner and start the timer marking the beginning of the test. Control the burner to a constant 150 ± 8 kW output. Control the hood duct flow to collect all products of combustion.
- Flame exposure. Continue the flame exposure until flame penetration of the test specimen and sustained flaming on the unexposed side occurs or for a period of 10 minutes, then extinguish the burner.
- Observation. If sustained flaming on the unexposed side of the test specimen has not occurred, observe the unexposed side of the test specimen for an additional 60 minutes for evidence of sustained flaming or glowing combustion on the unexposed side. Terminate the observation prior to the completion of the 60-minute observation period if all evidence of flame, glow and smoke has disappeared.
Note: An infrared thermometer has been found to be useful to detect the increase of temperature on the unexposed side of the test assembly. 9. Documentation. Perform photographic and/or video documentation before, during and after each test.
2025 CALIFORNIA REFERENCED STANDARDS CODE 39
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MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR WILDFIRE EXPOSURE
12-7A-1.10 Report. The report shall include the following:
Name and address of the testing laboratory.
Name and address of test sponsor.
Description of the test specimen including construction details of the wall system, including details of individual components (such as type, thickness and installation method of any sheathing) and the manufacturer’s installation details and limitations as applicable.
Number of specimens tested.
Description of weathering, as applicable.
Moisture content of hygroscopic elements of wall system construction at the time of testing.
Details of the burner verification, including heat supply rate.
Date of test, test identification number and date of report.
The test results shall include:
9.1. A notation of the time and location of sustained flaming on the unexposed side of the test specimen during the test, along with the sequence number of the test specimen. 9.2. A determination of the presence of glow on the unexposed side of the test specimen at the end of the 60-minute observation period. 9.3. Observations of the burning characteristics of the exposed surface of the test wall during and after the flame
exposure.
12-7A-1.11 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.
- Absence of flame penetration through the wall assembly at any time.
- Absence of evidence of glowing combustion on the interior surface of the assembly at the end of the 70-minute test.
Frequently asked questions
What exactly fails the SFM 12‑7A‑2 window test?
Any flame penetration through the window frame or glazing or any structural failure of the frame or glazing at any time during the required 8‑minute exposure is a failure per § 12‑7A‑2.8.
Can a larger window be tested if the standard fixture only supports 3 ft?
Yes — the standard notes that larger windows may be tested by expanding the size of the rear wall of the Wall Assembly Test Module; coordinate with the testing lab to confirm the chamber configuration. § 12‑7A‑2.6
Does a 20‑minute fire‑protection rating automatically satisfy the wildfire test?
A glazing assembly with a 20‑minute fire‑protection rating tested to NFPA 257 or UL 9 is listed as an acceptable glazing under § 504.8; it is an alternate compliance path but is separate from the SFM 12‑7A‑2 wildfire direct‑flame test.
What must the test report include to demonstrate compliance?
Reports must describe the window unit (frame, cladding, panes), installation details, times and locations of glass breakage, flame‑through or frame failure, and burner verification details as required by § 12‑7A‑2.7 and related reporting clauses.
If a specimen does not penetrate during exposure, is there more observation required?
Yes — the test conduct and observation provisions require continued observation for possible sustained combustion per the referenced procedures; follow the timing and observation rules in § 12‑7A‑2.7.
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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