Blasting standards

This handy reference guide to industry blasting standards is also available in poster format from our Blastrite offices in Cape Town, Durban and Johannesburg.  

Rust grades
Steel surface largely covered with adhering mill scale but little, if any, rust. Steel surface which has begun to rust and from which the mill scale begun to flake. Steel surface on which the mill scale has rusted away or from which it can be scraped, but with slight pitting visible under normal vision. Steel surface on which the mill scale has rusted away and on which general pitting is visible under normal vision.
Light blast cleaning
A commercial blast-cleaned surface, when viewed without magnification, shall be free of all visible oil, grease, dust, dirt, mill scale, rust, coating, oxides, corrosion products and other foreign matter. Random staining shall be limited to no more than 33 percent of each unit area of surface and may consist of light shadows, slight streaks or minor discolorations caused by stains of rust, stains of mill scale or stains of previously applied coating.
Thorough blast cleaning
A commercial blast-cleaned surface, when viewed without magnification, shall be free of all visible oil, grease, dust, dirt, mill scale, rust, coating, oxides, corrosion products and other foreign matter. Random staining shall be limited to no more than 5 percent of each unit area of surface, and may consist of light shadows, slight streaks or minor discolorations caused by stains of rust, stains of mill scale or stains of previously applied coating.
Very thorough blast cleaning
A commercial blast-cleaned surface, when viewed without magnification, shall be free of all visible oil, grease, dust, dirt, mill scale, rust, oxides, corrosion products and other foreign matter.