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Roofing contractors must install roofing systems that building codes and insurance. Fire ratings for roof systems are rated two ways; from above the roof and fire exposure from under the roof. The fire ratings are focused into three classes; Class A, Class B, and Class C. Roof Rating Process The process to test roofing fire ratings is governed by a process called ASTM E108 which standardizes fire tests of various roof coverings. The tests include simulated fire exposure to the exterior or outside of the roof. The tests measure the spread of flame across the surface of a roof and the ability of the roof covering material to resist fire’s penetration from the exterior to the interior of the building. The tests also help to determine if the roof covering material will turn into flying burning material after ignition. The classification of “flying material” is subjected to a 12-mph wind. On surface materials that are not considered to be combustible like steel or concrete, the tests are relegated to only the exterior roof. According to the ASTME E108 Class A rated roofs have a maximum flame spread of six feet. Class B roofs have a flame spread of eight feet. Finally, Class C roofs have a flame spread of thirteen feet. Because steeper slopes have an additional opportunity of melted material feeding the fire. Therefore class ratings are for the steepest or maximum slope roof. Classification Testing Methods In general the testing that is done corresponds to the classification of the roofing materials. In additional to three main tests, additional tests such as the burning brand test, flying brand test, and rain tests are all incorporated for a well-rounded measure of fire resistance. Class A tests are used to test roof coverings that are rated to be effective against severe or strong test exposure. They also have a high level of fire resistance to the roof deck, stay in position, and do not pose a flying brand hazard. Class B tests are used for roof coverings that are rated to be effective against moderate test exposure. The coverings have an average test exposure. They also have a moderate level of fire resistance, stay in position, and present no flying hazard. Class C tests are only for materials that offer limited fire resistance. As with the other tests, Class C tests also ensure that materials stay in place and do not pose a flying hazard. General Material Classification In very general terms, you can think of the following materials in terms of classification: - Gravel surface and ballasted single-ply – Class A
- Mineral surface – Class B
- Unsurfaced or asphalt gazing – Class C or even unrated In areas prone to fires, especially drier areas, be sure to evaluate the materials used in your roofing project to maximize your fire protection. Insurance providers also routinely offer discounts on home owners insurance when roofing materials are made with Class A or fire resistant materials. Be sure to check with your insurance agent on the levels of discount available to your policy. David Schulte is the president of Schulte Roofing and has served Bryan-College Station, Houston, Brenham and the surrounding areas for over 18 years. To learn more about College Station roofing contractors, visit their site at: http://www.schulteroofing.com
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Roof Fire Ratings, Schulte Roofing, College Station roofing contractors,
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