Frequently Asked Questions
What is a fire rating?
‘Fire Rating’ means that a material's reaction under fire conditions has been measured. The two main reactions from a material in a fire are "burn-through resistance" and "flame spread."
What is burn through resistance?
Burn through resistance is the ability of a material or assemblies of materials to prevent or retard the passage of high heat or flames. Burn through resistance rating is the time in minutes or hours that a material or assembly will resist fire exposure as determined by standard tests. The ASTM
E-119 is commonly specified by codes to determine the rating of walls.
One, two, three and four hour ratings are normally used. To achieve these ratings, most materials, including steel, concrete and wood, need to be protected. The most common protection is gypsum wallboard.
Blazeguard® is an excellent alternative to gypsum wallboard protected assemblies, especially where weight, thickness, and abuse resistance are considerations in the wall design.
| Blazeguard®, OSB substrate |
7/16" |
20 minutes |
| Untreated Plywood |
3/4" |
15 minutes |
| FRT Plywood |
1/2" |
6-8 minutes |
| Untreated Plywood |
1/2" |
7-9 minutes |
What is flame spread?
‘Flame Spread’ is the property of a material to restrict the spread (travel) of flame. A flame spread rating measures the time it takes for flame to travel along the surface of a material in a standard ASTM E-84 tunnel test. In this test a material is subjected to a calibrated gas flame in a wind tunnel. After ten minutes, the distance of the flame advance and how fast it advances are turned into an index. Materials are then classified as "A", "B", or "C". Materials having ratings poorer than "C" are usually not allowed in any space occupied by humans. All Blazeguard® products are Class "A" on the barrier side. The rating limit of Class "A" is an index of 25. Blazeguard® provides clearly superior performance with a flame spread index on plywood of 5.
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