Tech Today

Revised wind maps

Wind resistances of asphalt shingles are one of the primary performance considerations that should be evaluated when specifying asphalt shingle products. Recent changes to wind-load design procedures have resulted in a need for designers to reconsider how to specify asphalt shingles' wind resistances.

Wind resistance

Since the early 1970s, asphalt shingles' wind resistances have been tested according to a fan-induced wind test method described in ASTM D3161, "Standard Test Method for Wind-Resistance of Asphalt Shingles (Fan-Induced Method)." With this test method, asphalt shingle products are classified as Class A, D or F, which represent maximum test velocities of 60 mph, 90 mph or 110 mph, respectively.

UL 997, "Wind Resistance of Prepared Roof Covering Materials," is a test method similar to ASTM D3161 with similar classification designations.