The major test criteria in the area of fire resistance for built-up roofing are ASTM E-108, UL (Underwriters Laboratories) 790 and FM (Factory Mutual System) Class I. Only completely specified system configurations – including combustible or noncombustible deck, insulation type and thickness and fastening – can potentially receive these approvals. Individual products are not eligible.

ASTM E108 Test Methods for Fire Tests of Roof Coverings

ASTM E-108 and UL 790 are virtually identical tests of how well a roofing system resists fire, but there is a difference. A certification of passing an ASTM E108 test indicates that the system, as tested, passed the criteria for this test method.

For example, the video below demonstrates how the AlphaGuard MT system performs in an ASTM E-108 test, compared to typical thermoset and thermoplastic membranes.

UL 790 Test Methods for Fire Tests of Roof Coverings

A UL 790 classification indicates that UL witnessed the construction of the panels using representative materials from the manufacturer. It also indicates that the materials used in a classified system carry a UL label, meaning that UL periodically analyzes them and inspects their production to assure that they are the same as those tested. Additionally, UL reserves the right to periodically retest any system at their discretion to assure that the system is still capable of passing the test. A UL 790 classification will satisfy the requirements of ASTM E-108. However, passing ASTM E-108 is not equivalent to UL 790 classification. Be sure to check the specifics of the applicable code requirements on this important safety-related issue before specifying a system.

Tremco Roofing has an in-house fire test laboratory capable of testing products to either ASTM E108 or UL 790 test criteria. Our laboratory testing apparatus is so accurate and test procedures so rigorous that it is the only roofing material manufacturer's test laboratory at which UL will confer a UL 790 classification.

This valuable asset can substantially reduce the time necessary to obtain approval for a new system configuration and can aid in the rapid design of a new system that will obtain approval.

FM 4470 Approval Standards

FM Global is a large insurance underwriter of buildings. They have established criteria for roof construction and performance that make, in their estimation, a particular roof an acceptable risk to insure.

An FM Global system approval implies the successful FM testing of a roof system to FM 4470 test criteria. These criteria include fire resistance (I-60 or I-90), hail damage testing, fastener corrosion resistance, ultra-violet weathering and leakage. Only those systems meeting all of the criteria will receive a class I rating and be FM Global approved. Class I roofs are sub-classified as I-60 or I-90 for wind uplift and A, B or C for the ASTM E108 rating. They also indicate slope limitations as part of their approval.

Failure to meet any of the FM criteria will automatically result in Class II approval. FM standards require the installation of sprinkler systems in the buildings with Class II approval.

Understanding the various codes and approvals and their ramifications represents a critical element in the proper design and specification of a roofing system.