Roofing Material Fire Ratings

Astm ul 790 tests for fire resistance of roof covering materials underwriters laboratories has defined the ul 790 standard tests of roofing material fire resistance to external fire sources.

Roofing material fire ratings.

Fires that originate outside of the structure itself. In a recent roofing column we focused upon technical information that could be found on roofing material wrappers that could verify compliance with various building codes. The slope of the test specimen is preselected and since steeper slopes are more of a challenge due to melting material feeding the fire the rating applies to the maximum slope passed. Common underlying materials include a type 72 roll roofing material also known as 72 pound felt or 72 pound capsheet material and a panelized gypsum product called densdeck.

Class a does not mean grade a roofing systems are rated by realistic fire tests. Class c fire resistant roofing material. Understanding roof fire ratings class a roofing. The maximum flame spread is 6 feet for a class a rated roof 8 feet for class b and 13 feet for class c.

This month let s take a closer look at one particular type fire ratings. Class a roofing is the preferred choice for any home but this type of roofing is particularly important if you live in an area that is prone to wildfires to achieve a class a rating the roof must be effective against severe fire exposure. Ul 790 underwriters laboratories roof fire ratings a b c tests. But by including a particular underlying material it can meet the requirements for a class a roof.