1. Condition of metal surface: rust free, heavy mill scale, rusted, etc.
2. Length of service desired.
3. Type of metal surface.
4. Type of exposure: interior, exterior, moisture, chemical.
5. Topcoat system.
6. Application: equipment type, dry time required, temperature of application.

B. STEEL SURFACE PREPARATION SPECIFICATIONS
Two major factors must be considered. First is MILL SCALE, which is the thin layer of iron oxides that is formed on structural steel after hot rolling and shaping. Mill scale is not an integral part of the steel. It will be found in two conditions: either loose, or intact and tightly adhering to the steel.

Due to the differences in expansion rates between steel and mill scale, temperature change can rupture the bond between the two and adversely affect the continuity of any paint film applied to it.

The second factor is SURFACE PROFILE. Structural steel has an uneven surface, both before surface preparation and after cleaning. This is generally referred to as “mil profile” when expressing the depth of surface irregularities and can vary from 1 mil up to 4 mils. It is this condition that makes the film build of paint an important factor.

Also, because the mil profile can be controlled by the particle size of abrasive used when sand blasting, it is not uncommon to specify the maximum profile allowable when exposure conditions will be severe.

The following are general descriptions of the SSPC surface preparation specifications. Refer to the latest SSPC manual for the complete and official specifications. In addition, the closest equivalent of NACE and/or Swedish Standards has been listed for reference.

SSPC-SP-1 Solvent Cleaning	Solvent cleaning is a method of preparing steel surfaces by cleaning with solvent vapor, alkali, emulsion (detergent) or steam. This method removes visible oil, grease, dirt, soil, salts, and other soluble contaminants from steel surfaces. Prior to solvent cleaning, remove heavy oil or grease with a scraper. Next, remove foreign matter by one or a combination of the following: brush with stiff fiber or wire brushes, abrade, or clean with solutions of appropriate cleaners, provided such cleaners are followed by a fresh water rinse. After solvent cleaning, remove dirt, dust, and other contaminants by brushing, vacuuming, or blowing with clean dry air.
SSPC-SP-2, Swedish Standard ST-2 Hand Tool Cleaning	Hand tool cleaning is a method of preparing steel surfaces by the use of non-powered hand tools. Using hand tools, remove all loose mill scale, loose rust, loose paint, and other detrimental foreign matter. It is not intended that adherent mill scale, rust, weld slag or paint be removed by this process. Mill scale, rust and paint are considered adherent if they cannot be removed by lifting with a dull putty knife. The edges of remaining old paint should be feathered to give the repainted surface a reasonably smooth appearance.
SSPC-SP-3 Power Tool Cleaning	Power tool cleaning is a method of preparing steel surfaces by the use of power assisted hand tools. Using power tools, remove loose mill scale, loose rust, loose paint, and other detrimental foreign matter. Rotary or impact power tools can be used to remove stratified rust (rust scale) and weld slag. Caution: Do not burnish the surface. It is not intended that adherent mill scale, rust, and paint be removed by this process. Mill scale, rust, and paint are considered adherent if they cannot be removed by a dull putty knife. The edges of remaining old paint should be feathered to give the repainted surface a reasonably smooth appearance.
SSPC-SP-11 Power Tool Cleaning To Bare Metal	This specification covers the requirements for power tool cleaning to produce a bare metal surface and to retain or produce a surface profile. This specification is suitable where a roughened, clean, bare metal surface is required, but where abrasive blasting is not feasible or permissible. Metallic surfaces that are prepared according to this specification, when viewed without magnification, shall be free of all visible oil, grease, dirt, dust, mill scale, rust, paint, oxide, corrosion products, and other foreign matter. Slight residues of rust and paint may be left in the lower portion of pits if the original surface is pitted.
SSPC-SP-7, NACE 4, Swedish Standard Sa 1 Brush-Off Blast Cleaning	Brush-off blast cleaning is a method of preparing steel surfaces by use of abrasive blasting. Using an abrasive along with compressed air, water, or both, remove all dirt, dust, loose mill scale, loose rust, and loose paint. Tightly adherent mill scale, rust, and paint may remain on the surface. Mill scale, rust and paint are considered adherent if they cannot be removed by a dull putty knife.
SSPC-SP-6, NACE 3 Swedish Standard Sa 2 Commercial Blast Cleaning	Commercial blast cleaning is a method of preparing steel surfaces by use of abrasive blasting. Using an abrasive along with compressed air, water, or both, remove all dirt, dust, loose mill scale, loose rust, and loose paint. Evenly dispersed, very light shadows, streaks or discolorations caused by stains of rust or stains of previously applied paint may remain on no more than 33% of each square inch of surface area.
SSPC-SP-10, NACE 2 Swedish Standard Sa 2-1/2 Near-White Blast Cleaning	Near-white blast cleaning is a method of preparing steel surfaces by use of abrasive blasting. Using an abrasive along with compressed air, water, or both, remove all dirt, dust, loose mill scale, loose rust, and loose paint. Evenly dispersed, very light shadows, streaks or discolorations caused by stains of rust or stains of previously applied paint may remain on no more than 5% of each square inch of surface area.
SSPC-SP-5, NACE 1 Swedish Standard Sa 3 White Metal Blast Cleaning	White metal blast cleaning is a method of preparing steel surfaces by use of abrasive blasting. Using an abrasive along with compressed air, water, or both, remove all dirt, dust, loose mill scale, loose rust, and loose paint. The completed surface shall be cleaned to a gray-white metallic color. Uniformity of color may be affected by the grade of the metal, original surface condition, or shadowing from blast cleaning patterns.
SSPC-SP-12, NACE 5 High- and Ultrahigh-Pressure Water Jetting	This standard describes the surface preparation technique known as water jetting, which provides an alternative method of removing coating systems, including lead-based paint systems. Water jetting is effective in removing (1) deleterious amounts of water-soluble surface contaminants that may not otherwise be removed by dry abrasive blasting alone, specifically in the bottom of pits and craters of severely corroded metallic substrates; (2) surface grease and oil; (3) rust; (4) shot-creting spatter; and (5) existing coatings and linings.

Choose from the following list of substrates:

• Aluminum
• Copper
• Galvanized Metal
• Masonry & Concrete
• Steel
• Wood
• Weathered Vinyl Siding

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