Surface Cleaning Standards

The four main standards of blast cleaning for steel surfaces include Brush Off, Commercial, Near White Metal and White Metal, with each reaching a different level of cleaning. Please consult with your local standards organisation to obtain complete specifications regarding the degrees of surface cleanliness for your country.

Brush Off

SA-1
SSPC-SP7
NACE No. 4
Swedish Standards Organisation
Steel Structures Painting Council (USA)
National Association of Corrosion Engineers
 

Brush Off Blast Cleaning is the standard of surface preparation, which when viewed with magnification is free of all visible oil, grease, dirt, dust, mill scale, rust, paint and coatings. Tightly adherent mill scale, rust, old paint and coatings may remain on the surface. Mill scale rust, old paint and coatings are considered adherent if they cannot be removed by lifting with a blunt putty knife.

Commercial

SA-2
3rd Quality
SSPC-SP6
NACE No. 3
Swedish Standards Organisation
United Kingdom Standards (BS 4232)
Steel Structures Painting Council (USA)
National Association of Corrosion Engineers
 

Commercial Blast Cleaning is the standard of surface preparation, which when viewed with magnification is free of all visible oil, grease, dirt, dust, mill scale, rust, paint and coatings. Generally, evenly dispersed very light shadows, streaks and discolorations caused by stains of rust, mill scale or previously applied paint or coatings may remain on no more than 33% of the surface. If the original surface is pitted, slight residues of rust, paint and coatings may also be left in the craters of pits.

Near White Metal

SA-2.5
2nd Quality
SSPC-SP10
NACE No. 2
Swedish Standards Organisation
United Kingdom Standards (BS 4232)
Steel Structures Painting Council (USA)
National Association of Corrosion Engineers
 

Near White Metal Blast Cleaning is the standard of surface preparation, which when viewed with magnification is free of all visible oil, grease, dirt, dust, mill scale, rust, paint and coatings. Generally, evenly dispersed very light shadows, streaks and discolorations caused by stains of rust, mill scale or previously applied paint or coatings may remain on no more than 5% of the surface.

White Metal

SA-3
1st Quality
SSPC-SP5
NACE No. 1
Swedish Standards Organisation
United Kingdom Standards (BS 4232)
Steel Structures Painting Council (USA)
National Association of Corrosion Engineers
 

White Metal Blast Cleaning is the standard of surface preparation, which when viewed with magnification is free of all visible oil, grease, dirt, dust, mill scale, rust, paint and coatings. It is assumed that prior to treatment, the steel surface has been cleaned of dirt and grease, and that the heavier layers of rust have been removed by chipping.ST2 - Thorough scraping and wire-brushing - machine brushing - grinding - etc. The treatment shall remove loose mill scale, rust and foreign matter. Finally, the surface is cleaned with a vacuum cleaner, clean dry compressed air or a clean brush. It should have a faint metallic sheen. The appearance shall correspond to the prints designated ST2.


It is assumed that prior to treatment, the steel surface has been cleaned of dirt and grease, and that the heavier layers of rust have been removed by chipping.

ST2 - Thorough scraping and wire-brushing - machine brushing - grinding - etc. The treatment shall remove loose mill scale, rust and foreign matter. Finally, the surface is cleaned with a vacuum cleaner, clean dry compressed air or a clean brush. It should have a faint metallic sheen. The appearance shall correspond to the prints designated ST2.