This document specifies a method for assessing the degree of rusting of surfaces coated with paints and varnishes (organic coatings), with metallic coating plus an organic coating (duplex coating) and with metallic coatings only (e.g. hot-dip galvanized steel) by comparison with pictorial standards. The standard can also be used for bare metal surfaces. The pictorial standards provided in this document show surfaces which have deteriorated to different degrees by a combination of rust broken through the coating and visible under-rusting. The assessing of the degree of rusting of this document is only an estimation of the affected area on specimen. Edges are not included. 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 Annex C, Table C.1. NOTE 2 The correlation between the ISO scale and the rating system of ASTM D610-08 is given in Annex C, Table C.2. ISO 4628-1 describes the system used for designating the quantity and size of defects and the intensity of changes in appearance of coatings and outlines the general principles of the system. This system is intended to be used, in particular, for defects caused by ageing and weathering, and for uniform changes such as colour changes, for example yellowing.