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 Table 503.1. Class 1, Class 2 or Class 3, ignition-resistant construction shall be in accordance with Sections 504, 505 and 506, respectively. Materials required to be ignition-resistant materials shall comply with the requirements of Section 503.2.
IGNITION-RESISTANT CONSTRUCTIONa
| DEFENSIBLE SPACEc | FIRE HAZARD SEVERITY | |||||
| Moderate Hazard | High Hazard | Extreme Hazard | ||||
| Water Supplyb | Water Supplyb | Water Supplyb | ||||
| Conformingd | Nonconforminge | Conformingd | Nonconforminge | Conformingd | Nonconforminge | |
| Nonconforming | IR 2 | IR 1 | IR 1 | IR 1 N.C. | IR 1 N.C. | Not Permitted |
| Conforming | IR 3 | IR 2 | IR 2 | IR 1 | IR 1 | IR 1 N.C. |
| 1.5 × Conforming | Not Required | IR 3 | IR 3 | IR 2 | IR 2 | IR 1 |
- Access shall be in accordance with Section 403.
Subdivisions shall have a conforming water supply in accordance with Section 402.1.
IR 1 = Ignition-resistant construction in accordance with Section 504.
IR 2 = Ignition-resistant construction in accordance with Section 505.
IR 3 = Ignition-resistant construction in accordance with Section 506.
N.C. = Exterior walls shall have a fire-resistance rating of not less than 1 hour and the exterior surfaces of such walls shall be noncombustible . Usage of log wall construction is allowed.
- Conformance based on Section 603.
- Conformance based on Section 404.
- A nonconforming water supply is any water system or source that does not comply with Section 404, including situations where there is no water supply for structure protection or fire suppression.
Ignition-resistant building materials shall comply with any one of the following:
Material shall be tested on all sides with the extended ASTM E84 (UL 723) test or ASTM E 2768, except panel products shall be permitted to test only the front and back faces. Panel products shall be tested with a ripped or cut longitudinal gap of 1/8 inch (3.2 mm). Materials that, 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 E 2768, comply with the following:
- 1.1. Flame spread. Material shall exhibit a flame spread index not exceeding 25 and shall not show evidence of progressive combustion following the extended 30-minute test.
- 1.2. Flame front. Material shall exhibit a flame front that does not progress more than 101/2 feet (3200 mm) beyond the centerline of the burner at any time during the extended 30-minute test.
1.3. Weathering. Ignition-resistant building materials shall maintain their performance in accordance with this section under conditions of use. Materials shall meet the performance requirements for weathering (including exposure to temperature, moisture and ultraviolet radiation) contained in the following standards, as applicable to the materials and the conditions of use:
- 1.3.1. Method A "Test Method for Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing" in ASTM D 2898, for fire-retardant-treated wood, wood-plastic composite and plastic lumber materials.
- 1.3.2. ASTM D 7032 for wood-plastic composite materials.
- 1.3.3. ASTM D 6662 for plastic lumber materials.
1.4. Identification. Materials shall bear identification showing the fire test results.
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.
- Noncombustible material. Material that complies with the requirements for noncombustible materials in Section 202.
- Fire-retardant-treated wood. Fire-retardant-treated wood identified for exterior use and meeting the requirements of Section 2303.2 of the International Building Code.
- Fire-retardant-treated wood roof coverings. Roof assemblies containing fire-retardant-treated wood shingles and shakes that comply with the requirements of Section 1505.6 of the International Building Code and classified as Class A roof assemblies as required in Section 1505.2 of the International Building Code.