Section 503 — IGNITION-RESISTANT CONSTRUCTION AND MATERIAL

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

Exceptions:

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

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

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

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

SPECIAL BUILDING CONSTRUCTION REGULATIONS

503.2.2 Fire-retardant-treated wood. Fire-retardant-treated wood shall be identified for exterior use and shall meet the requirements of Section 2303.2 of the California Building Code .

503.2.3 Fire-retardant-treated wood roof coverings. Roof assemblies containing fire-retardant-treated wood shingles and shakes shall comply with the requirements of Section 1505.6 of the California Building Code and shall be classified as Class A roof assemblies as required in Section 1505.2 of the California Building Code .

503.2.4 Other ignition-resistant building material. Material shall be tested on the front and back faces in accordance with the extended ASTM E84 or UL 723 test, for a total test period of 30 minutes, or with the ASTM E2768 test. The materials shall bear identification showing the fire test results. Panel products shall be tested with a ripped or cut longitudinal gap of [1] / 8 inch (3.2 mm). The materials, when tested in accordance with the test procedures set forth in ASTM E84 or UL 723 for a test period of 30 minutes, or with ASTM E2768, shall comply with Sections 503.2.4.1 through 503.2.4.3.

Exception: Materials composed of a combustible core and a noncombustible exterior covering made from either aluminum at a minimum 0.019 inch (0.48 mm) thickness or corrosion-resistant steel at a minimum 0.0149 inch (0.38 mm) thickness shall not be required to be tested with a ripped or cut longitudinal gap.

503.2.4.1 Flame spread. The material shall exhibit a flame spread index not exceeding 25.

503.2.4.2 Flame front. The material shall exhibit a flame front that does not progress more than 10 feet 6 inches (3200 mm) beyond the centerline of the burner at any time during the test.

503.2.4.3 Weathering. Ignition-resistant building materials shall maintain their performance in accordance with this section under conditions of use. The materials shall meet the performance requirements for weathering (including exposure to temperature, moisture and ultraviolet radiation) contained in Sections 503.2.4.3.1 through 503.2.4.3.3, as applicable to the materials and conditions of use.

503.2.4.3.1 Evaluation requirements for weathering. Fire-retardant-treated wood, wood-plastic composite materials and plastic lumber materials shall be evaluated after weathering in accordance with Method A “Test Method for Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing” in ASTM D2898.

503.2.4.3.2 Wood-plastic composite materials. Wood-plastic composite materials shall also demonstrate acceptable fire performance after weathering by the following procedure: first testing in accordance with ASTM E1354 at an incident heat flux of 50 kW/m [2] in the horizontal orientation, then weathering in accordance with ASTM D7032 and then retesting in accordance with ASTM E1354 and exhibiting an increase of no more than 10 percent in peak rate of heat release when compared to the peak heat release rate of the nonweathered material.

503.2.4.3.3 Plastic lumber materials. Plastic lumber materials shall also demonstrate acceptable fire performance after weathering by the following procedure: first testing in accordance with ASTM E1354 at an incident heat flux of 50 kW/m [2] in the horizontal orientation, then weathering in accordance with ASTM D6662 and then retesting in accordance with ASTM E1354 and exhibiting an increase of no more than 10 percent in peak rate of heat release when compared to the peak heat release rate of the nonweathered material.

503.2.5 Surface treatment protection. Use of paints, coatings, stains or other surface treatments are not an approved method of protection as required in this chapter.

Building material, systems, assemblies and methods of construction shall be tested in accordance with the standards specified in Chapter 5.

503.3.1 Qualification by testing. Material and material assemblies tested in accordance with the requirements of Section 503 shall be accepted for use when the results and conditions of those tests are met. Product evaluation testing of material and material assemblies shall be approved or listed by the State Fire Marshal or identified in a current report issued by an approved agency.

503.3.2 Approved agency. Product evaluation testing shall be performed by an approved agency in accordance with Section 1703 of the California Building Code. The scope of accreditation for the approved agency shall include building product compliance with this code.

503.3.3 Labeling. Material and material assemblies tested in accordance with the referenced standards shall bear an identification label showing the fire test results. That identification label shall be issued by a testing and/or inspecting agency approved by the State Fire Marshal.

1. Identification mark of the approved testing and/or inspecting agency.

2. Contact and identification information of the manufacturer.

3. Model number or identification of the product or material. 4. Pretest weathering specified in this chapter. 5. Compliance standard as described under Chapter 7.

503.3.4 Fire-retardant-treated wood shingles and shakes. Fire-retardant-treated wood shingles and shakes shall be approved and listed by the State Fire Marshal in accordance with Section 208(c), Title 19 California Code of Regulations.

� SECTION 504—IGNITION-RESISTANT CONSTRUCTION