Levels of Sandblasting

Solvent Cleaning (SSPC SP1)

• This first level of sandblasting uses water and minerals to remove solvent-soluble foreign matter from the surface of ferrous metal. This process uses low pressure and high volume water cleansing with solvents such as the hydrocarbon xylol or toluol, a form of the chemical toluene. Surfaces are cleaned with this method before using hand tools to blast equipment. Rags and solvents are replenished frequently in this process to avoid spreading foreign matter instead of removing it.

White-Metal Blasting (SSPC SP5)

• White-metal blasting removes rust and contaminants from metals constantly immersed in water or liquid chemicals. It's used when the maximum performance of protective coating is necessary because of the severe conditions of immersion. When completed, a surface cleaned with a white-metal blast will be gray-white, uniform in its metallic color and slightly rough. The surface will be free of all oil, grease, dirt, rust, corrosion products, oxides, paint, other foreign matter or mill scale. Mill scale is the iron oxide scale formed on steel during hot working processes, cooled in air

Commercial Blast (SSPC-SP6)

• A commercial blast removes all oil, grease, dirt, rust scale and foreign matter from the surface. Slight shadows, streaks or discolorations caused by rust stain, mill scale oxides or slight, tight residues of paint or coating may remain after a commercial blast application. If the surface is pitted, slight residues or rust or paint may remain at the bottom of the pits. In a commercial blast at least two-thirds of each square inch of the surface area must be free of all visible residues. The remainder must be limited to light discoloration.

Brush-Off Blast (SSPC SP7)

• A brush-off blast completely removes all oil, grease, dirt, rust scale, loose mill scale, loose rust and loose paint or coatings. With this level of sandblasting, tight mill scale and tightly adhered rust, paint and coatings are permitted to remain as long as all the mill scale and rust have been exposed to the blast pattern. The exposure to the blast pattern must expose the numerous flecks of the underlying metal uniformly distributed over the entire surface.

Near-White Blast (SSPC -- SP10)

• A near-white blast, removes all oil, grease, dirt, mill scale, rust, corrosive products, oxides, paint and other foreign matter. Light shadows, very slight streaks or slight discolorations from rust stain, mill scale oxides or light, tight residues or paint or coating may remain. At least 95 percent per square inch of surface area must be free of all visible residues. The remaining surface area must have limited discoloration from the residues. A near-white blast is a practical surface preparation for existing plant facility maintenance.