Fire Rating Of Roof Systems

Astm e108 defines fire test methods for roof coverings.

Fire rating of roof systems.

The highest fire resistance rating for roofing as per astm e 108. 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. The ratings are as follows. Fire ratings for roofs are classified as either class a class b class c or are unrated if a roof covering cannot meet the requirements for any of these classifications.

Your roof can have one of four fire ratings classifications. Roofing systems must meet or exceed building codes and insurance requirements. 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. Class a is the highest rating offering the highest resistance to fire and unrated is the worst.

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. As applied to elements of buildings the fire resistance rating classifies the ability of an assembly to confine and isolate fire within a zone comprised of fire resistance rated walls ceiling and floor assemblies. Roofing systems are rated by realistic fire tests. We must emphasize however that individual roof components are not rated at all.

Roof insulation fire performance before the latest amendments to adb the key fire consideration for flat roofing was requirement b4 which covered the resistance to fire from the outside of a roof system where achieving f ac to bs476 3 in the past and now b roof t4 gave unrestricted distance to the boundary of the building. Fire rated wall floor and ceiling assemblies provide the necessary fire and smoke barriers to create compartmentalization during a fire safeguarding against the spread of fire and smoke within a building or to and from a building. Class a class b class c or unrated. This non profit organization founded in 1894 devotes to testing and to establishing of fire safety standards.

A class a roof is ideal for fire protection and may be required by your building codes depending on your place of residence. How are roofs rated. Roof covering packaging that encloses shingles or other roofing that have a fire rating will display the level of fire or wind resistance rating of the materials. The most widely accepted standards for fire resistance in building materials are those of underwriters laboratories inc.

Fires that originate outside of the structure itself. Underwriters laboratories has defined the ul 790 standard tests of roofing material fire resistance to external fire sources. These assemblies need to meet fire and smoke safety and environmental sustainability requirements. The ratings relate to fire tests designed to determine how quickly fire can raise the temperature to unacceptable levels.