This International Standard specifies a chart rating system based on standard charts 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. This International Standard takes into account only pitting corrosion resulting from penetration of the protective anodic oxidation coating. NOTE ISO 8994[3] describes a similar rating system based on defined grids.