humidity, dew point, and surface and ambient air temperature shall be
measured and recorded. Humidity shall be determined in accordance with
ASTM E 337. No work shall be performed unless the conditions specified in
paragraph Atmospheric and Surface Conditions are met.
3.3.1.2
Presurface Preparation Inspection
The Coating Inspector shall identify and mark all areas requiring
preparation prior to abrasive blasting as specified in paragraph Pit, Edge,
and Weld Preparation as well as areas requiring solvent-type cleaning. The
entire work surface does not need to be inspected at one time, but rather
the Coating Inspector may choose to mark up work areas as the job
progresses. Identified areas shall be marked with an indelible marker.
Pit depth shall be measured with any suitable pit depth gage. Irregular
shaped pits shall be identified visually.
3.3.1.3
Surface Preparation Inspection
The Coating Inspector shall inspect all prepared surface for compliance
with the specification. Blasted surfaces shall be inspected for compliance
with the requirements of SSPC SP 5. Surfaces cleaned to a lesser degree
than SSPC SP 5 shall be reblasted and inspected.
a.
Abrasive Blast Air Cleanliness. Compressed air cleanliness shall
be evaluated by the Coating Inspector on a daily basis at the
beginning of the work shift in accordance with ASTM D 4285. The
air compressor shall be allowed to warm up and air discharged
under normal operating conditions to allow accumulated moisture to
be purged. An absorbent clean white cloth shall be held in the
stream of compressed air not more than 600 mm 24 inch from the
point of discharge for a minimum of one minute. The air shall be
checked as near as possible to the point of use and always after
the position of the in-line oil and water separators. The cloth
shall then be inspected for moisture or staining. The compressed
air source shall not be used if there is any oil or water
contamination present.
b.
Recycled Blast Media Cleanliness and Shape. The Coating Inspector
shall evaluate the cleanliness of recycled blast media on a daily
basis at the beginning of the work shift. A clear glass container
is half filled with new or recycled abrasive and distilled or
deionized water is added to fill the container. The resulting
slurry mixture is stirred or shaken and allowed to settle. The
water is then examined for the presence of an oil sheen. If a
sheen is present then the media shall not be used and the source
of contamination shall be identified and corrected. Recycled
steel grit blast media shall be inspected at minimum once for
every four hours of blasting for compliance with paragraph
Abrasive Media requirements for number of round and half-round
particles. Recycled steel grit working mixtures with greater than
15 percent round or half-round particles shall be immediately
disposed or reconstituted by the addition of a suitable quantity
of new steel grit abrasive to the working mixture. The particle
shape of the reconstituted steel grit shall be retested prior to
the commencement of blasting.
c.
Blast Profile. The Coating Inspector shall measure the surface
profile depth in accordance with ASTM D 4417, Method C. The mean
value of three profile measurements taken within a 103 cm2 16 in2
SECTION 09971A
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