SSPC-SP5 / NACE 1 cleaning standard is most stringent in terms of what aspect?

The SSPC-SP5 / NACE 1 cleaning standard, known as "White Metal Blast Cleaning," is indeed the most stringent standard when considering staining levels on a surface. This standard requires that all visible rust, mill scale, and foreign contaminants be removed, resulting in a surface that is free from any discoloration or staining. Specifically, the guideline dictates that the surface must appear uniformly metallic and shiny, with no visible remnants of contaminants, which is crucial for optimal paint adhesion and overall coating performance.

Staining levels are critical because any residual staining could compromise the performance of the coating, potentially leading to adhesion failure, premature corrosion, and other issues. Thus, the emphasis on achieving the highest degree of cleanliness ensures that the subsequent coatings adhere well and perform according to their specifications.

While surface roughness, paint adhesion, and blast technique are important factors in the overall effectiveness of coating applications, they do not represent the primary focus of the SSPC-SP5 / NACE 1 standard in the same way as the requirement for stringent cleanliness regarding staining.