The amount of rusting beneath or through a paint film is a significant factor in determining whether a coating system should be repaired or replaced. This practice provides a standardized means for quantifying the amount and distribution of visible surface rust.

The degree of rusting is evaluated using a zero to ten scale based on the percentage of visible surface rust.

The distribution of the rust is classified as spot rust, general rust, pinpoint rust or hybrid rust.

1.1 This practice covers the evaluation of the degree of rusting on painted steel surfaces. The visual examples which depict the percentage of rusting given in the written specifications form part of the standard. In the event of a dispute, the written definition prevails. These visual examples were developed in cooperation with SSPC: The Society for Protective Coatings to further standardization of methods. The photographs can be used to estimate the percentage of other coating defects on various substrates. This standard does not include evaluation of rust propagation around an initially prepared scribe, score, or holiday.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.