ISO 4628-3:2003 describes a method for assessing the degree of rusting of coatings by comparison with pictorial standards.
The pictorial standards provided in this part of ISO 4628 show coated steel surfaces which have deteriorated to different degrees by a combination of rust broken through the coating and visible underrust.
NOTE 1 The pictorial standards have been selected from the European rust scale published by the European Confederation of Paint, Printing Ink and Artists' Colours Manufacturers' Associations (CEPE), Brussels. The correlation between the ISO scale and the European rust scale is given in an annex.
NOTE 2 The correlation between the ISO scale and the rating system of ASTM D 610, Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces, is also given in an annex.