area constitutes a spot measurement. The minimum number of spot
measurements per unit area shall be 3 per 45 m2 500 ft2. The spot
measurements shall be randomly spaced. The surface profile for
each 45 m2 500 ft2 area shall conform to the requirements of
paragraph Abrasive Blasting. Spot measurements shall be performed
on weldments and flame-cut edges. At least one spot measurement
shall be performed for each 15 m 50 ft of weld. At least one spot
measurement shall be performed for each 3 m 10 ft of flame-cut
edge. Each spot measurement on welds or flame-cut edges shall
conform to the requirements of paragraph Abrasive Blasting. Areas
not meeting the profile requirement shall be reblasted and
inspected for blast profile.
d.
Contaminants on Prepared Surface. Abrasive blasted surfaces that
have been swept, blown down, or vacuum cleaned to remove residual
debris and dust shall be visually inspected for grease, oil, and
dust. The Coating Inspector shall use any suitable test to
enhance the visual inspection for grease and oil including water
break, solvent evaporation, and heat tests. The grease and oil
inspection shall be performed at least once per work day or every
four hours of blasting. The Coating Inspector shall inspect the
cleaned surfaces for residual dust using the tape test. The tape
test is performed by adhering a clear piece of tape to the
surface. The removed tape is inspected for adherent particles.
At a minimum the Coating Inspector shall perform the tape test
once per 45 m2 500 ft2 of prepared surface.
3.3.1.4
Metallized Coating Inspection
a.
Equipment Setup Validation Bend Test. Each day or every time the
thermal spray equipment is to be used the Coating Inspector shall
record and confirm that the operating parameters are the same as
were used to prepare the JRS. The thermal spray applicator shall
then apply the coating to prepared test panels and conduct the
bend test. The bend test is a qualitative test used to confirm
that the equipment is in proper working condition. The test
consists of bending coated steel panels around a cylindrical
mandrel and examining the coating for cracking. The results of
the bend test shall be recorded and the test panels labeled and
saved. The test panels shall consist of five cold rolled steel
panels measuring 75 x 150 x 1.25 mm 3 x 6 x 0.050 inch. The
panels shall be cleaned, blasted, and coated using the identical
surface preparation procedures and spray parameters as used to
prepare the working surface. The coating shall be applied in a
cross hatch pattern using the same number of overlapping spray
passes as used to prepare the JRS. The coating thickness shall be
measured to confirm that the coating thickness is within the
specified range. Test panels shall be bent 180 degrees around a
steel mandrel of a specified diameter. Thermal spray coating
systems 1-Z, 2-Z, 4-Z-A, 5-Z-A, 7-A, and 8-A shall be tested using
a 12.5 mm 0.5 inch diameter mandrel. Systems 3-Z and 6-Z-A shall
be tested using a 15.6 mm 0.625 inch diameter mandrel. A
pneumatic or manual mechanical bend test apparatus shall be used
to bend the test panels. Test panels shall be examined visually
without magnification. If the bend test fails, corrective action
shall be taken and the bend test repeated until acceptable results
are achieved. No metallizing shall be performed on the working
surface prior to the successful completion of the bend test.
SECTION 09971A
Page 26
Previous Page
