SA 1 indicates which level of blast cleaning?

The designation SA 1 refers to a specific standard of surface preparation known as "Light Blast Cleaning." This level indicates that the surface has been cleaned to remove rust, mill scale, and other contaminates effectively. In this case, the surface is not stripped to its bare metal but is adequately prepared for the application of coatings.

In the context of surface preparation standards, SA 1 signifies using abrasive materials to achieve a light clean, which often means some foreign materials remain but to a significantly reduced degree compared to unprepared surfaces. It is commonly used in situations where a complete removal of contaminants is not necessary, offering a balance between efficacy and efficiency.

Understanding SA 1 is crucial for coatings inspectors, as it directly influences the type of coating that can be applied to a surface, the adhesion properties, and ultimately the longevity and performance of the coating system. The other options represent different levels of surface preparation, each with specific purposes, which is why they do not accurately represent the SA 1 classification.