This joint standard covers the use of blast cleaning abrasives to achieve a defined degree of cleaning of steel surfaces prior to the application of a protective coating or lining system. This standard is intended for use by coating or lining specifiers@ applicators@ inspectors@ or others whose responsibility it may be to define a standard degree of surface cleanliness. The focus of this standard is brush-off blast cleaning. White metal blast cleaning@ near-white blast cleaning@ commercial blast cleaning@ and industrial blast cleaning are addressed in separate standards. Brush-off blast cleaning provides a lesser degree of cleaning than industrial blast cleaning (SSPC-SP 14/NACE No. 8). The difference between an industrial blast and a brush-off blast is that the objective of a brush-off blast is to allow as much of an existing coating to remain as possible@ and to roughen the surface prior to coating application while the purpose of the industrial blast is to remove most of the coating@ mill scale and rust@ when the extra effort required to remove every trace of these is determined to be unwarranted. This joint standard was prepared by the SSPC/NACE Task Group A on Surface Preparation by Abrasive Blast Cleaning. This joint Task Group includes members of both the SSPC Surface Preparation Committee and the NACE Unit Committee T-6G on Surface Preparation (now STG 04).