Roof Assembly Fire Class Criteria

Examples of a by assembly fire rating include fire retardant treated wooden shakes and aluminum roof coverings.

Roof assembly fire class criteria. Class a roof assemblies are those that are effective against severe fire test exposure. Class a roof assemblies and roof coverings shall be listed and identified as class a by an approved testing agency. A roofing membrane that is classified as part of a class a assembly when installed over a particular insulation may not qualify as part. Tested roof systems are fire classified class a b or c where the most fire resistant roof assemblies are class a and class c is least resistant.

Fire ratings may pertain to resistance to fire from above the roof system the familiar class a b or c ratings or fire exposure from the building interior the underside of the roof deck. Assembly rated class a roof coverings are those that meet class a standards when combined with other elements. Test conditions and pass criteria are shown in table 1. 6 usg fire resistant assemblies test certification test conditions and fire and sound tested assemblies listed in this selector are based on characteristics properties and performance certificationof materials and systems obtained under controlled test conditions as set forth in the appropriate astm standard in effect at the time of test.

It should be noted that these classifications apply to roofing assemblies and not the roofing membrane. For roof assemblies with combustible decks wood plank t g astm e 108 and ul 790 require two additional fire tests. 1505 2 class a roof assemblies class a roof assemblies are those that are effective against severe fire test exposure. But by including a particular underlying material it can meet the requirements for a class a roof.

For example shake roofing with a fire retardant treatment rates class b on its own but achieves a class a rating when combined with specified underlying materials such as type 72 roll roofing material. Roofing assembly classification will need to be for each roofing project. 1 an intermittent flame test in which the flame is turned on and off during the roof assembly to resist. Building code fire resistance requirements building codes establish fire resistance requirements for roofs based on the type of construction e g concrete steel wood for the building.

Our roof systems are rated by code for external fire resistance under deck exposure and time temperature resistance. Class a roof assemblies shall be permitted for use in buildings or structures of all types of construction. Class a roof assemblies and roof coverings shall be listed and identified as class a by an approved testing agency. We must emphasize however that individual roof components are not rated at all.

These listings are short summaries to serve as a. Class a does not mean grade a roofing systems are rated by realistic fire tests. An exterior fire retardant treated shake roof has a stand alone class b rating.