Roof Assembly Fire Class

Class a roof assemblies and roof coverings shall be listed and identified as class a by an approved testing agency.

Roof assembly fire class.

In accordance with these standards all classified roof covering assemblies fall into one of the three following categories. According to the scope of fm 4470. Class a roof assemblies are those that are effective against severe fire test exposure. Examples of a by assembly fire rating include fire retardant treated wooden shakes and aluminum roof coverings.

The class 1 rating is an exclusive designation that can only be awarded by fm global which indicates the successful testing of the entire roof assembly using fm approval standard 4470. 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. An exterior fire retardant treated shake roof has a stand alone class b rating. Assembly rated class a roof coverings are those that meet class a standards when combined with other elements.

Includes roof coverings which are effective against moderate fire exposures. The best rating achieved is class a which is described by ul as effective against severe fire exposure class 1 rating. Includes roof coverings which are effective against severe fire exposures class b. But by including a particular underlying material it can meet the requirements for a class a roof.