Coating Application 8 4 Residual Contaminants 8. Brush Application 8. Roller Application 8. Significance and Use Notch Gages 3.
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A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. Scope 1. It includes the key elements of surface preparation, coatings application, and? The items should be selected that are pertinent to the speci? Available from Materials manufacturer. See Guide D for establishing procedures to certify inspectors for coatings work in nuclear facilities.
The values given in parentheses are for information only. Current edition approved Feb. Published March Originally approved in Last previous edition approved in as D — Referenced Documents 2. Many of the details covered may be in a speci? Request Adjunct No. D — 07 project. A speci? A checklist for use in the? Preparation for Inspection 4. The inspector should examine these materials and be supplied with appropriate protective equipment and devices.
Surface Preparation Methods and Requirements 5. The speci? The standard is used by the inspector to assist in determining whether the degree of surface preparation speci? For large jobs it is recommended that before work starts, an actual steel sample of adequate size be blasted to the satisfaction of the project engineer.
This blasted surface should be protected by a clear acrylic coating or encased in plastic and used for reference purposes as the work progresses. These include oil, grease, soil, weld spatter, and slag, that make it impossible to obtain proper adhesion to the metal surface. Deposits of salt such as chlorides and sulfates should be removed, or longterm coating performance will be seriously affected.
SSPC issues detailed surface preparation speci? This scale is very brittle and can crack or loosen due to temperature changes both in fabricating and weathering in the?
Coarser abrasives generally produce a coarser and deeper pro? Deep pro? A general recommendation is that the surface pro? This recommendation does not apply if the resulting pro?
The angularity sharpness and density of the pro? Methods for measuring surface pro? Each has its own safety-related hazards, and U. Occupational Health and Safety Administration regulations should be followed. Materials Safety Data Sheets MSDS for the solvents and cleaning compounds provided by the manufacturer should also be consulted for proper worker protection.
The solvent is applied to the surface by wiping or scrubbing with rags or brushes. The contaminants should be removed not simply spread out by a thorough wiping of the affected areas with cloths saturated with clean solvent. Contaminated cloths should not be dipped into clean solvent. The cleaning should be repeated with clean rags and fresh clean solvent.
Emulsions, cleaning compounds, steam cleaning, or similar methods and materials may also be used. Where emulsion cleaners, soaps, or detergents are used, they should be removed completely by washing with clean hot water. Vapor cleaning removes all soluble contaminants but does not disturb the natural oxide? If this? The part to be cleaned is placed in the saturated vapor above the heated solvent so that the solvent vapor condenses on the metal surface.
Vapor degreasing does not remove particulate matter, so parts should be wiped to remove any insoluble soils. Vapor degreasing has the advantages over solvent wiping in that hot solvents are used and the solvent condensation removes oils without recontamination.
Material is considered tightly adherent if it cannot be lifted with a dull putty knife. SSPC provides a detailed speci? Brushes should be kept free of all materials that may clog the wires of the brush. Scrapers should be kept sharp at all times. Hand tool cleaning in accordance with 5. All impact tools should be kept sharp. It also requires a minimum of 1-mil anchor pro?
Surface cleaning, power tools, and surface pro? Surface cleaning power tools consist of non-woven abrasive wheels and discs, coated abrasive discs or sanding pads, coated abrasive? Surface pro? All oil, grease, weld? Hand tool cleaning 5. Needle guns require 2-mm diameter needles to produce a suitable surface pro? Slight residues of rust and paint may remain in the lower portions of pits if the original surface was pitted. Staining is allowed on 33 percent of the evaluation unit area, and slight residues of rust and paint may remain in the lower portions of pits if the initial surface was pitted.
Water may be injected into the air stream to control dust, and a rust inhibitor may be needed. In another method used primarily in fabricating shop, wheels propel the abrasive centrifugally against the work. The minimum and maximum particle size of the abrasive may be speci? The compressed air used for blast cleaning should be free of condensed water or oil by making certain that separators and traps are in working order. Test the compressed air supply in accordance with Test Method D Blast cleaning is often performed from the top to bottom of the structure and should only be carried on downwind from any recently painted areas.
Dry blast cleaning operations should not be conducted on surfaces that will be wet after blasting and before painting. Note that Pictorial Surface Preparation Standards D is divided into two methods for abrasive blasting. The two sets of photographs are not directly comparable. C Pictorial Standard Sa 2 shows mill scale and con? Surfaces 4 D — 07 that have been dry blasted should be brushed with clean brushes, blown with compressed air free of oil and moisture, or vacuum cleaned to eliminate any traces of blast products, dust, or dirt from the surface.
This also serves to remove abrasive from pockets and corners. Reblasting will be necessary on any surface if rust bloom forms before coating can be applied. Pressures over KPa 20 psi are needed to achieve total coating removal when using only water.
Pressurized water alone will not remove mill scale efficiently, or impart an anchor pro? Inhibitors may be added to the water to prevent? The surface should be dried or allowed to dry before coating. It includes photographs with three levels of rustback, if allowed by the speci? All dust, dirt, oil, grease, moisture, soot, tar, or other contaminants should be removed from unpainted surfaces.
Previously painted surfaces should be similarly cleaned of all foreign matter; all deteriorated coating should be removed as well. Mortar or cement drippings from earlier repairs should be removed by mechanical or chemical means. Tree limbs or other growth obstructing the structure should be cut away to provide ready access. Blasting debris that accumulates on horizontal surfaces should be removed.
Special attention should be placed on examining hard to reach areas, the back side of nuts and bolts, sides of members in close proximity to other members or walls, and undersides of members. Alternatively, the surface may be allowed to weather a minimum of 6 months before cleaning and painting. Vapor degreasing or immersion in an alkaline or acid cleaning solution are commonly used in shop work. In the?
Lead pigmented primers should never be used over aluminum surfaces. The minimum treatment for aluminum is Type B, Method 3 of Practices D , which describes the use of an alcoholic phosphoric acid cleaner. The cleaning of each section, bay, or part of the work should be entirely completed, inspected, and accepted before any coating is applied.
The system of alternately cleaning and painting short sections by one workman is not good practice since this can lead to surface or intercoat contamination. It may sometimes be necessary to clean newly coated surfaces using some of the speci? Washing may also be necessary between coats of paint.
Be aware that standing water on uncured paint can result in early failure. Chloride from deicing salts or a marine environment, and sulfate contamination from air pollution have been recognized as main factors in premature breakdown of existing coating systems.