NACE WJ-4/SSPC-SP WJ 4 (R2021)

This joint standard is the first of four standards that describes the different degreees of surface cleanliness of coated or uncoated metallic substrates when using waterjet cleaning in preparation of applying a coating or lining. This standard describes Light Cleaning, which is used when the objective is to allow as much of the tighly adherent rust and other corrosion products, coating, and mill scale to remain as possible, but when the extra effort required to remove more of these materials is determined to be unwarranted. It includes procedures before and following a waterjet cleaning and immediately prior to coating or lining application, and appendices with explanatory notes, methods of assessing flash rust, and waterjetting equipment and operation parameters. This standard is maintained jointly by the SSPC and NACE Task Group 276.