ASTM D7158

ASTM D7158, Standard Test Method for Wind Resistance of Asphalt Shingles (Uplift Force/Uplift Resistance Method), is an ASTM International test that classifies how well sealed asphalt shingles resist wind. Unlike the fan test in ASTM D3161, it uses an engineering approach: the uplift force that wind would place on a shingle is compared with the shingle's measured mechanical resistance, which depends on its stiffness and the strength of its self-seal adhesive bond.

Because the classes are linked to the wind design methods of ASCE 7 (the US standard for minimum design loads), many engineers consider D7158 a closer reflection of real building conditions than D3161.

Classes

The class thresholds have changed as ASCE 7 changed. According to NRCA's Professional Roofing:

• 2005 edition (based on ASCE 7-02 nominal wind speeds): Class D up to 90 mph (145 km/h), Class G up to 120 mph (193 km/h), Class H up to 150 mph (241 km/h).
• 2016 edition (based on ASCE 7-10 ultimate design wind speeds, Vult): Class D up to 115 mph (185 km/h), Class G up to 150 mph (241 km/h), Class H up to 190 mph (306 km/h).

The 2016 classes apply to buildings in risk categories I to IV, in exposure B or C, with a mean roof height of 60 ft (18 m) or less. Outside those limits additional engineering calculation is needed. The Asphalt Roofing Manufacturers Association (ARMA) has published guidance on using D7158 when standard conditions do not apply.

Ongoing revision

Later ASCE 7 editions (ASCE 7-16 onward) raised pressure coefficients for steep-slope roofs. NRCA has advised designers to apply D7158 classes with caution where ASCE 7-16 or newer codes govern, since the published class limits were derived from older pressure coefficients.

Use in codes and programs

The International Building Code and International Residential Code require self-sealing asphalt shingles to be classified under D7158 (shingles without self-seal strips may instead use ASTM D3161 classes), with the required class set by the site's design wind speed. The IBHS FORTIFIED Roof program accepts D7158 Class H or D3161 Class F shingles.

What a rating means

A Class H label indicates that, under the assumptions of the standard, the sealed shingle's bond and stiffness provide enough resistance for the stated wind speed range. The rating assumes the shingles have fully sealed. Shingles installed in cold weather may not seal for weeks, and in that period they are more vulnerable than the rating suggests.