weekends. Contractor work hours should allow for
such during coating application.
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NOTE: Cold-weather application is not covered by
this specification. If a project is designed for
coating in cold weather, then the enclosure and
heating requirements may be significant. It is not
intended that contractors be forced to apply
coatings in cold weather, however, the underlying
premise is that coatings must be applied within the
specified temperature ranges. A cold-weather
specification should not be used to simply save
money, as the coating system will generally not have
the same longevity as one applied within 60-100
degrees F.
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The application condition requirements for the coating system are very time
and temperature sensitive, and are intended to avoid the delamination
problems frequently found on industrial structures. Plan coating
application to ensure that specified temperature, humidity, and
condensation conditions are met. If conditions do not allow for orderly
application of sealant, primer, stripe coat, intermediate coat and topcoat,
use appropriate means of controlling air and surface temperatures, as
required. Partial or total enclosures may be required, as well as other
measures, to control conditions to allow for orderly application of all
required coats.
Apply coating only when steel and internal air temperatures are between 16
and 38 degrees C 60 and 100 degrees F. Do not apply coatings above 38
degrees C 100 degrees F or below 16 degrees C 60 degrees F.
Use Table entitled "RECOAT WINDOWS" to determine appropriate recoat windows
for each coat after the initial coat. Apply each coating during
appropriate RECOAT WINDOW.
If coating is not applied during RECOAT WINDOW, apply during EXTENDED
RECOAT WINDOW. Application of any epoxy coat within the EXTENDED RECOAT
WINDOW requires application of a TACK COAT prior to applying any full coat.
Perform CURE TEST immediately prior to application of TACK COAT to
determine condition of applied coating. If CURE TEST indicates that
surface is fully cured, provide GLOSS REMOVAL prior to application of TACK
COAT.
If coating is not applied during EXTENDED RECOAT WINDOW, or if surface
temperature exceeds 49 degrees C 120 degrees F between applications,
provide GLOSS REMOVAL, apply TACK COAT, where applicable, within 24 hours,
and apply next full coat within TACK COAT RECOAT WINDOW.
RECOAT WINDOWS
Temperature degrees F
60-70
71-80
81-90
91-100
101-110
111-120
Temperature degrees C
16-21
22-27
28-32
33-38
39-43
44-49
RECOAT WINDOW (Hrs.)
24-72
18-60
16-48
12-36
8-18
4-6
EXTENDED RECOAT
72-168
60-140
48-120
36-96
18-36
6-12
SECTION 09973
Page 26
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