Roofing Material Fire Ratings

But by including a particular underlying material it can meet the requirements for a class a roof.

Roofing material fire ratings.

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. This month let s take a closer look at one particular type fire ratings. Understanding roof fire ratings class a roofing. Obviously since wildfires and the fire season has become increasingly worse it is important to note the roofing materials that are the lowest rated.

Ul 790 underwriters laboratories roof fire ratings a b c tests. 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. 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. 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.

Class c fire resistant roofing material. The maximum flame spread is 6 feet for a class a rated roof 8 feet for class b and 13 feet for class c. Fires that originate outside of the structure itself. An exterior fire retardant treated shake roof has a stand alone class b rating.