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...
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