SSPC SP 7
Brush-off Blast Cleaning
|Publication Date:||1 January 2007|
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 who may be responsible for defining a standard degree of surface cleanliness.
The focus of this standard is brush-off blast cleaning. White metal blast cleaning, near-white metal 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 cleaning and a brush-off blast cleaning is that the objective of a brushoff blast cleaning is to allow as much of an existing adherent coating to remain as possible and to roughen the surface prior to coating application, whereas the purpose of the industrial blast cleaning is to remove most of the coating, mill scale, and rust, while the extra effort required to remove every trace of these is determined to be unwarranted.
This joint standard was originally prepared in 1994 and revised in 2000 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. It was reaffirmed in 2006 by the SSPC Surface Preparation Committee, and NACE Specific Technology Group (STG) 04, Protective Coatings and Linings: Surface Preparation.
In SSPC/NACE standards, shall and must are used to state mandatory requirements. Should is used to state that which is considered good and is recommended but is not absolutely mandatory. May is used to state that which is considered optional.