Which of the following refers to the thorough hand and power tool cleaning level considered in the inspection process?

The selection of the standard that refers to thorough hand and power tool cleaning in the inspection process is accurate in identifying ISO St 3. This standard outlines the requirement for the preparation of steel surfaces by employing tools such as grinders, sanders, or other power tools to remove all rust, mill scale, and other contaminants to achieve a clean substrate suitable for coating application.

ISO St 3 specifies that the surface must be virtually free of all visible rust and mill scale, ensuring that any remaining contaminants are minimal and will not compromise the performance of the coating. Achieving this level of cleanliness is crucial in preparing surfaces to promote optimal adhesion and durability of the coating system that will be applied afterward.

In contrast, other standards referenced in the options address varying degrees of surface preparation that may not reach the same thoroughness as ISO St 3. Some may involve less rigorous cleaning methods, allowing for certain residues to remain, which would not be suitable for the highest quality coating application where surface integrity is paramount. This distinction emphasizes the importance of thorough cleaning in ensuring the success of coating longevity and performance.