colors. Standard trim colors are usually more
limited. Except where interior surfaces receive a
factory color coat, the exposed reverse side of the
panels normally are provided with an off-white
backer coating. Color other than manufacturer's
standard colors will be used only when the extra
cost is justified.
The choice of coating for the interior face of
panels depends on environmental and aesthetic
considerations. Where a corrosive atmosphere is
anticipated within the structure, the finish should
be PVF2 in a thickness appropriate to the
environment. For utilitarian facilities with little
likelihood of a detrimental atmosphere, a standard
backer coat is appropriate. Backer coat is the
manufacturer's standard coating (usually polyester
based) applied to the back side of the metal panel.
This coating is normally a wash coating and is not
controlled for consistent color or gloss. Where
interior surfaces are concealed behind insulation,
liner panels, etc.; provide only a primer coat.
These finishes should not be confused with a wash
coat which is used primarily to facilitate the coil
forming process and which is not closely controlled
for color, gloss or film thickness. The designer's
rationale for using any special interior finish
should be reflected in the design analysis.
Energy considerations must be included in the choice
of standard colors for the roof panels. White or
light-colored roofing surfaces are much better at
reflecting sunlight than darker surfaces. This
keeps roofs 20 to 35 degrees C (35 to 60 degrees F)
cooler, which means less heat will be transferred to
internal building spaces. Demonstration projects
have shown that cooling energy use can be cut by as
much as 40 percent when light-colored surfaces are
used. Coordinate the use of light-colored roofing
material with the user.
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Panels shall have a factory applied [polyvinylidene fluoride] [_____]
finish on the exposed side. The exterior finish shall consist of a
baked-on topcoat with an appropriate prime coat. Color shall match the
color indicated [on the drawings] [in Section 09915 COLOR SCHEDULE]. The
exterior coating shall be a nominal [0.025] [0.050] mm [1] [2] mil
thickness consisting of a topcoat of not less than 0.018 mm 0.7 mil dry
film thickness and the paint manufacturer's recommended primer of not less
than [0.005] [0.025] mm [0.2] [1.0] mil thickness. The interior color
finish shall consist of [the same coating and dry film thickness as the
exterior] [a nominal 0.025 mm 1 mil thick [PVF2] [_____] finish otherwise
the same as the exterior] [a backer coat with a dry film thickness of 0.013
mm 0.5 mil] [a 0.005 mm 0.2 mil thick prime coat]. The exterior color
finish shall meet the test requirements specified below.
2.6.1
Salt Spray Test
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SECTION 07416A
Page 19
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