This standard describes a test method for the determination of the resistance to carbonation of coatings and paints (UNE-EN 1504-2, EN 1504-1, EN 1504-3) applied on concrete, as well as the equivalent thickness with respect to the concrete, paste or mortar used as substrate or reference. The method does not measure the resistance to carbonation that may result from the absorption of gases (e.g. S02, HCl) other than carbon dioxide. This standard does not cover cores taken from existing construction works.