NRCA analyzes and tests metalJames R. Kirby, Bala Sockalingam
Contractor-fabricated architectural metal panel roof systems
have been used successfully in the United States for years.
However, there recently has been increased scrutiny about some of
these roof assemblies' wind uplift-resistance capabilities.
Building code requirements mandate minimum uplift resistances
for roof assemblies, and model building codes list approved test
methods that determine uplift resistances for roof assemblies that
cannot have uplift resistances determined analytically.
Underwriters Laboratories (UL) Inc. test method UL 580, "Tests for
Wind Uplift Resistance of Roof Assemblies," currently is the most
common method referenced in building codes as an approved test
method to determine uplift resistance of roof assemblies.
For most roofing products used in the United States, roofing
contractors rely on product manufacturers to perform testing and
provide the necessary documentation for building code compliance.
However, because there are no product manufacturers for
contractor-fabricated architectural metal panel roof systems, the
responsibility for providing code compliance information typically
resides with the contractor who fabricates and installs the metal
panels. Steel and aluminum have analytical design methodologies
that are industry-accepted; there is no industry-accepted
analytical design methodology for copper. Therefore, the uplift
resistances of copper panel roof systems must be determined through
physical testing.
Because of this, in 1997, NRCA embarked on a testing program for
contractor-fabricated copper panel roof systems. All metal panels
in this study are flat-pan with double-lock standing seams. NRCA
retained and analyses were performed by ENCON® Consultants
Inc., Tulsa, Okla., at the Hurricane Testing Laboratory in West
Palm Beach, Fla. As part of our study, theoretical analyses of
contractor-fabricated aluminum, Galvalume,™ galvanized steel,
terne-coated stainless steel and terne-coated carbon steel roof
panels were performed to determine uplift resistances according
to...
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