Blast Cleaning-Sa

Surface preparation by blast-cleaning is designated by the letters "a".

Prior to blast-cleaning, any heavy layers of rust shall be removed by chipping. Visible oil, grease and dirt shall also be removed.

After blast-cleaning, the surface shall be cleaned from loose dust and debris.

Sa 1 Light blast-cleaning

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from poorly adhering mill scale, rust, paint coatings and foreign matter.

Sa 2 Thorough blastcleaning

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from most of the mill scale, rust, paint coatings and foreign matter. Any residual contamination shall be firmly adhering.

Sa 2.5 Very thorough blast-cleaning

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from mill scale, rust, paint coatings and foreign matter. Any remaining traces of contamination shall show only as slight stains in the form of spots or stripes.

Sa 3 Blast-cleaning to visually clean steel

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and shall be free from mill scale, rust, paint coatings and foreign matter. It shall have a uniform metallic colour.

Hand and power tool cleaningSt

Surface preparation by hand and power tool cleaning, such as scraping, wire-brushing, machine-brushing and grinding, is designated by the letters "St".

Prior to hand and power tool cleaning, any heavy layers of rust shall be removed by chipping. Visible oil, grease and dirt shall also be removed.

After hand and power tool cleaning, the surface shall be cleaned from loose dust and debris.

St 2 Thorough hand and power tool cleaning

When viewed without magnification, the surface shall be free from visible oil, grease and dirt, and from poorly adhering mill scale, rust, paint coatings and foreign matter.

St 3.0 Very thorough hand and power tool cleaning

As for ST2.0 but the surface shall be treated much more thoroughly to give a metallic sheen arising from the metallic substrate.

NOTES: Preparation grade "St 1" is not included as it would correspond to a surface unsuitable for painting.