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    Author(s): S. L. LeVan; C. A. Holmes
    Source: (Research paper FPL ; 474):15 p. : ill. ; 28 cm.
    Publication Series: Research Paper (RP)
    Station: Forest Products Laboratory
    PDF: View PDF  (362 KB)


    Some building codes require wood shingles to be fire-retardant treated. Because exterior fire-retardant treatments are subjected to weathering, treatment durability and leach resistance are critical for insuring adequate fire protection. We examined the effectiveness of various fire-retardant treatments on wood after 0, 2, 5, and 10 years of outdoor exposure. We used a Class C burning-brand test (ASTM E 108) and a Schlyter flamespread test to evaluate effectiveness. Most shingle treatments evaluated were either pressure impregnated or coated at the Forest Products Laboratory; however, a commercial treatment was used as a control. After 10 years of exposure, most treatments passed the Class C burning-brand test, but lost considerable effectiveness in the Schlyter test method. The commercial treatment was the most effective after 10 years of weathering.

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    LeVan, S. L.; Holmes, C. A. Effectiveness of fire-retardant treatments for shingles after 10 years of outdoor weathering. (Research paper FPL ; 474):15 p. : ill. ; 28 cm.


    Shingles, Weathering, Thuja plicata, Leach resistance, Class-C burning brand test, Schlyter test., Western redcedar

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