metal roofing system manufacturer to install the system, and shall have a
minimum of three years experience as an approved applicator with that
manufacturer. The applicator shall have applied five installations of
similar size and scope as this project within the previous 3 years.
1.6.5
Single Source
Roofing panels, clips, closures, and other accessories shall be standard
products of the same manufacturer; shall be the latest design by the
manufacturer; and shall have been designed by the manufacturer to operate
as a complete system for the intended use.
1.6.6
Laboratory Tests For Panel Finish
The term "appearance of base metal" refers to the metal coating on steel.
Panels shall meet the following test requirements:
a.
Formability Test: When subjected to a 180 degree bend over a 3 mm
1/8 inch diameter mandrel in accordance with ASTM D 522, exterior
coating film shall show only slight microchecking and no loss of
adhesion.
b.
Accelerated Weathering Test: Withstand a weathering test for a
minimum of 2000 hours in accordance with ASTM G 23, Method 1
without cracking, peeling, blistering, loss of adhesion of the
protective coating, or corrosion of the base metal. Protective
coating that can be readily removed from the base metal with a
penknife blade or similar instrument shall be considered to
indicate loss of adhesion.
c.
Chalking Resistance: After the 2000-hour weatherometer test,
exterior coating shall not chalk greater than No. 8 rating when
measured in accordance with ASTM D 4214 test procedures.
d.
Color Change Test:
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NOTE: In general, only colors such as white, beige,
and tan will not exceed the 2 NBS units requirement.
To allow for heavier pigmented colors, specify
color change not to exceed 5 NBS units for a
3000-hour weatherometer test.
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After the [2000] [_____]-hour weatherometer test, exterior coating
color change shall not exceed [2] [_____] NBS units when measured
in accordance with ASTM D 2244 test procedure.
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NOTE: For projects located in high temperature and
humidity or corrosive atmospheres or where premium
finish would be justified, use:
Salt spray test: Rating of 10, no blisters in field
Rating of 7, 2 mm 1/16 inch edge creep
Abrasion Resistance Test: 100 liters
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SECTION 07611N
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