ISO 8994:2011 specifies a grid rating system that provides a means of defining levels of performance of anodic oxidation coatings on aluminium and its alloys that have been subjected to corrosion tests.
This rating system is applicable to pitting corrosion resulting from
- accelerated tests,
- exposure to corrosive environments, and
- practical service tests.
ISO 8994:2011 takes into account only pitting corrosion of the basis metal resulting from penetration of the protective anodic oxidation coating.