NOTE: The 70 percent polyvinylidene fluoride finish
has a minimum abrasion resistance of about 65 liters
per 0.025 mm (65 liters/mil) of coating thickness.
The nominal 0.025 mm (1 mil) finish will withstand
50 to 60 liters of sand while the nominal 0.050 mm
(2 mil) finish can be expected to withstand 80-100
liters. The results of this test are variable and
offer poor repeatability. In shop drawing review,
notice the difference between the specified total
liters of sand and those reported.
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When subjected to the falling sand test in accordance with ASTM D 968,
Method A, the coating system shall withstand a minimum of [50] [80] liters
of sand before the appearance of the base metal. The term "appearance of
base metal" refers to the metallic coating on steel or the aluminum base
metal.
2.6.7
Specular Gloss
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NOTE: Few manufacturers regularly produce
prefinished panels meeting these low gloss
requirements and such sheets are available only in
limited colors. Standard 70 percent PVF2 finish,
for example, has a medium gloss. Low gloss paint
formulations result in reduced weathering
properties. Identify individual facilities
requiring low gloss finish.
For roof of structures at airfields where glare
would be objectionable and may be an operational
hazard, the specular gloss value should be limited
to 10 or less at an angle of 85 degrees.
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Finished roof surfaces for [_____] shall have a specular gloss value of [10
or less at an angle of 85 degrees] [30 plus or minus [_____] at 60 degrees]
when measured in accordance with ASTM D 523.
2.6.8
Coating shall show no visual effects when covered spot tested in a 10
percent hydrochloric acid solution for 24 hours in accordance with ASTM D
1308.
2.7
INSULATION
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NOTE: Drawings will show type, R-Value, vapor
barrier, extent and location of insulation,
including insulation retainer system. Insulation
retainer system consists of a grid of bands and
cross bands and their connections to hold the
insulation neatly in place and against the bottom of
occur. The insulation retainer system will be
detailed on the drawings and specified to allow a
SECTION 07416A
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