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 proportional to the degree of surface preparation and cleaning. Reduction in the degree of surface
preparation is usually accompanied by a proportionate reduction in performance. Various degrees of
surface preparation specifically relating to gradations in performance have not been established, nor can
they be assessed with any degree of confidence. There are also certain trade-offs, such as, cost, time,
abrasive equipment availability, grit disposal, dust, and machinery contamination that must be
considered. Therefore, every effort should be made to achieve or approach the optimum surface within
the constraints encountered in each situation. Ideally, the non-skid coating system should be applied over
a metal surface, which is free of corrosion products, and other contaminants, degreased, and coated with
the approved metal primer.
(1) Steel surfaces should be finished to a white metal finish (SSPC-SP5), or to a near-white metal
finish (SSPC-SP10), as defined in the Steel Structures Painting Manual volume 2.
(a) Blast cleaning to white metal (SSPC-SP5) is the ultimate, and is used to prepare surfaces where
the coatings must withstand exposure to very corrosive atmospheres and where a high cost of surface
preparation is warranted. Blast cleaning to white metal requires the complete removal of all rust, mill
scale, and other contaminants from the surface.
(b) In a near-white metal blast (SSPC-SP10), there may be shadows, streaks, discolorations, and
blemishes across the blasted surface area, but not concentrated in spots. (Evaluation of cleaning results
is based on visual examination.) Near-white metal preparation provides a 10 to 35 percent savings over
white metal blasting and has proven to be adequate for many of the special coatings developed for long-
term protection in moderately severe environments.
(2) Aluminum surfaces shall be cleaned free of corrosion products, dirt, and other contaminants by
light abrasive blasting with 80 grit aluminum oxide or garnet abrasive. A pressure of 65 psig has resulted
in satisfactory surface preparation with minimal metal removal. The surface can be spot cleaned after
blasting by power brushing or orbital sanding. Aluminum shall be cleaned only with clean, dry sand,
stainless steel wire brushes, stainless steel pads, or 1PD-455 specification abrasive sanding discs not
used previously for cleaning other metals or for removal of copper or mercury pigmented paints. If not
painted immediately or if contaminated with oil or grease, the aluminum should be washed with a liquid
detergent cleaner, thoroughly rinsed with freshwater, and allowed to dry completely.
d. Renewal and Reapplication. Nonskid surfaces must be renewed when operations indicate that slip
resistance has become unsatisfactory as a result of wear or coating failure. Surfaces may be renewed by
over coating the existing coating; the decision to recoat should be based on a thorough examination. If
the existing coating is worn but otherwise sound (intact), it can be successfully over coated. Wear is
shown by loss of nonskid characteristic (grit is worn flush with coating film); a sound surface condition is
shown by relatively few bare areas, no significant rusting, no corrosive undercutting (indicated by easily
removable nonskid flakes or sheets), and by good adhesion (indicated by difficulty in removing a test
patch by chipping or scraping). If examination reveals large bare areas, significant corrosion, or poor
adhesion, the old nonskid coating should be removed and the surface properly prepared before
reapplication of nonskid Coating. The degree of adhesion of the new coating will depend on the quality of
cleaning and surface preparation.
(1) A section of the deck should be roped off to eliminate nonessential traffic. The deck must be
cleaned free from rust, oil, loose paint, and other contaminants by either mechanical or chemical means
or, as a combination of the two, degreased and then coated with epoxy polyamide.
(2) In view of the time and effort required for surface preparation, care should be exercised to protect
the surface by priming immediately (within 1 hour) after it is cleaned and dried in order to prevent rust and
other surface contamination. Although priming within 1 hour is generally recommended, the priming of
steel can often be delayed for longer periods without serious effects under favorable conditions; that is,
conditions of low humidity and freedom from surface contamination, or when the surface can be certified
to conform to a near-white metal blast, SSPC-SPC-10.
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