There are two representative international standards for cleaning levels: one is the "SSPC-" formulated by the United States in 1985; the second is the "Sa-" formulated by Sweden in 1976, which is divided into four levels: Sa1, Sa2, , Sa3, is the international common standard.

　　Level is commonly used in industry and can be used as acceptance technical requirements and standards. The technical standard of grade treatment: the same as the first half of Sa2 requirements, but the defect is limited to no more than 5% per square meter of the surface, which may include slight shadows; A small amount of slight discoloration caused by defects and rust; oxide scale and paint defects.

　　Details are as follows:

　　Sa1 level-equivalent to the US SSPC-SP7 level. The general simple method of manual brushing and emery cloth polishing is the lowest level of the four cleanliness. The protection of the coating is only slightly better than that of the untreated workpiece.

　　Technical standard for Sa1 treatment: Oil, grease, residual scale, rust, and residual paint should not be seen on the surface of the workpiece.

　　Sa2 level-equivalent to the US SSPC-SP6 level. The sandblasting method is adopted, which is the lowest level in sandblasting, which is a general requirement, but the protection of the coating is much higher than that of manual brushing.

　　Technical standard for Sa2 treatment: no greasy, dirt, scale, rust, paint, oxide, corrosives, and other foreign substances (except flaws) shall be visible on the surface of the workpiece, but the flaws shall be limited to no more than per square meter 33% of the surface may include slight shadows; slight discoloration caused by defects and rust; oxide scale and paint defects. If the original surface of the workpiece has dents, slight corrosion and paint will remain on the bottom of the dents.

　　Sa3 level-the level is equivalent to the US SSPC-SP5 level, is the highest processing level in the industry, also known as the white cleaning level (or white level). The technical standard of Sa3 level processing: as with the level, 5% shadows, defects, rust, etc., all have to exist.