R390.3 Definitions
The following words and terms shall, for the purpose of this Section, have the meanings shown herein.
Defensible Space
An area either natural or manmade, where material capable of allowing a fire to spread unchecked has been treated, cleared or modified to slow the rate and intensity of an advancing wildfire and to create an area for fire suppression operations to occur.
Defensible Space Standard
The Colorado State Forest Service publication, Protecting Your Home from Wildfire: Creating Wildfire-Defensible Zones, 2012 Quick Guide is an approved standard for meeting the defensible space requirements of Section R390.4.12 or for the creation of a wildfire mitigation plan.
Fire Retardant Treated Wood
Wood products that, when impregnated with chemicals by a pressure process or other means during manufacture, exhibit reduced surface-burning characteristics and resist propagation of fire, as defined in IBC 202 and IRC R202. Wood meeting the requirements of Section R802.1.5 of the International Residential Code® or Section 2303.2 of the International Building Code®.
Heavy Timber Construction (Type IV, HT)
Construction with wood framing members, columns, flooring and roof decks sized in accordance with International Building Code® Section 602.4.
Ignition-Resistant Building Material
Ignition-resistant building materials shall comply with any one of the following:
1. Extended ASTM E 84 testing. Material shall be tested on all sides with the extended ASTM E 84 (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 E 84 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 10-½ 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. All materials shall bear identification showing the fire test results.
Exception:
Materials comprised of a combustible core and a noncombustible exterior covering, comprised of 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.
2. Noncombustible material. Material that complies with the requirements for noncombustible materials in this section, including but not limited to approved materials as follows:
2.1 Cementitious stucco
2.2 Cementitious cladding
2.3 Metal sheeting comprised of 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.
3. Fire-retardant-treated wood. Fire-retardant-treated wood labeled for exterior use. Where a section also specifies fire-retardant-treated wood with a dimensional thickness, the specified dimension at a minimum is required.
Log Wall Construction
A type of construction in which exterior walls are constructed of solid wood members and where the smallest horizontal dimension of each solid wood member is at least 6-inches (152 mm).
Multilayered Glazed Panels
Window or door assemblies that consist of two or more independently glazed panels installed parallel to each other, having a sealed air gap in between, within a frame designed to fill completely the window or door opening in which the assembly is intended to be installed.
Noncombustible
As applied to building construction material means a material that, in the form in which it is used, is either one of the following:
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- Material of which no part will ignite and burn when subjected to fire. Any material conforming to ASTM E 136 shall be considered noncombustible within the meaning of this Section.
- Material having a structural base of noncombustible material as defined in Item 1 above, with a surfacing material not over 1/8 inch (3.2 mm) thick, which has a flame spread index of 50 or less. Flame spread index as used herein refers to a flame spread index obtained according to tests conducted as specified in ASTM E 84 or UL723.
“Noncombustible” does not apply to surface finish materials. Material required to be noncombustible for reduced clearances to flues, heating appliances or other sources of high temperature shall refer to material conforming to Item 1. No material shall be classified as noncombustible that is subject to increase in combustibility or flame spread index, beyond the limits herein established, through the effects of age, moisture or other atmospheric condition.
Wildfire Mitigation Plan
A wildfire mitigation plan addresses the risk of wildfire both to the subject property and those posed to neighboring properties in the surrounding area by the proposed development through appropriate site location for structures, construction design and the use of ignition-resistant building material, defensible space and fuel reduction around structures, driveway access for emergency vehicles and an emergency water supply for firefighting in accordance with Article 4-804(C.)(12.) and Article 4-806(A.)(5.) of the Boulder County Land Use Code.
Wildfire Partners
Wildfire Partners is a collaborative Boulder County wildfire hazard mitigation program for homeowners that helps to reduce the risk of damage to homes from wildland fire. In Wildfire Partners, homeowners take personal responsibility for preparing their home and property for wildland fire and actively participate in an onsite assessment with a wildfire mitigation specialist. When participants complete their customized wildfire mitigation plan and pass their follow up inspection, they receive a Wildfire Partners Certificate and may be eligible for financial assistance (www.wildfirepartners.org).