SSPC-SP5/NACE 1 is the standard for white metal blast cleaning, which is one of the highest levels of surface cleanliness in the coatings industry. This standard specifies that the surface must be free of all visible oil, grease, dirt, dust, rust, mill scale, and other foreign matter. In terms of staining, the specification limits any staining to 0% per unit area. This means that there should be no discernible staining on the surface, ensuring that the substrate is in optimal condition for coating application. Achieving a completely clean surface is critical for proper adhesion and performance of the coating.
Other choices reflect allowances for certain levels of staining, which do not apply to the stringent requirements of SSPC-SP5/NACE 1. This emphasis on a flawless surface condition ensures that the applied coatings will achieve their intended protective and aesthetic functions effectively.