Fire Rating Of Roof Systems

These assemblies need to meet fire and smoke safety and environmental sustainability requirements.

Fire rating of roof systems.

Class a is the highest rating offering the highest resistance to fire and unrated is the worst. The highest fire resistance rating for roofing as per astm e 108. 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. 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.

The ratings are as follows. Underwriters laboratories has defined the ul 790 standard tests of roofing material fire resistance to external fire sources. 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. A class a roof is ideal for fire protection and may be required by your building codes depending on your place of residence.

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. This non profit organization founded in 1894 devotes to testing and to establishing of fire safety standards. These tests may be conducted at ul inc fm global or any other certified testing laboratory. Roofing systems must meet or exceed building codes and insurance requirements.

Astm e108 defines fire test methods for roof coverings. Your roof can have one of four fire ratings classifications. Fires that originate outside of the structure itself. We must emphasize however that individual roof components are not rated at all.

Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building. Class a class b class c or unrated. Roofing systems are rated by realistic fire tests. The ratings relate to fire tests designed to determine how quickly fire can raise the temperature to unacceptable levels.

Our roof systems are rated by code for external fire resistance under deck exposure and time temperature resistance. The most widely accepted standards for fire resistance in building materials are those of underwriters laboratories inc. 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. How are roofs rated.