During recent years, there has been debate in the U.S. roofing industry regarding the appropriateness and applicability of tear-strength testing for evaluating fiberglass-reinforced asphalt strip shingles. This debate usually involves shingle manufacturers who indicate tear-strength testing is an unreliable, inadequate predictor of shingle performance and users of asphalt shingles who contend it is one of the only quantifiable measures available for assessing asphalt shingles.
In 2001, NRCA began a limited research project where the tear-strength values of a number of asphalt shingles were tested in an as-received condition and after condensation conditioning, heat aging and five years. The research results provide some useful information for assessing the appropriateness and applicability of tear-strength testing for fiberglass-reinforced asphalt strip shingles.
In 2001, NRCA obtained samples of 15 fiberglass-reinforced asphalt strip shingle products represented to be warranted by manufacturers for 25 years and comply with ASTM D3462, "Standard Specification for Asphalt Shingles Made from Glass Felt and Surfaced with Mineral Granules." The products were procured from throughout the U.S. through normal distribution sources by NRCA technical committee members. Product sample lots consisted of a minimum of five bundles of asphalt shingles in their original packaging for each product analyzed.