No. 10VOC Class “B” Clear Fire Retardant Penetrating Wood Treatment was developed to meet requirements for a clear fire retardant treatment for EXTERIOR use on previously untreated cedar shakes and shingles. It is very effective in reducing the flammability of Cedar and other edge grain woods. No. 10VOC contains no water soluble salts, therefore it’s fire retardant properties are lasting. Properly treated wood will char but will not support combustion.

Fire Test:

(small Scale) A cedar shingle was divided in half. One section was treated with two coats of No. 10 at 300 sq. ft./gal per coat, allowed to dry 72 hours, and then placed at a 450 angle for an incline fire test. A Fisher high temperature gas burner, with flame temperature of 1800F was placed two inches from the panel surface. The flame was removed at 15 and 30 second intervals, and the time for the surface to self extinguish was recorded as follows:
Flame Exposure Time to Self Extinguish Smoke Developed
15 seconds 1 4 seconds
30 seconds 2 continuous burning
60 seconds 3
90 seconds 6
120 seconds 15

Flame Spread Rating:

Class “B” per NFPA 703 Section 2-2.1.3. Applied to No. 1 grade Red Cedar Shingles and tested in accordance with ASTM E 84 Tunnel Test