ISO 8251:2011 specifies the following three test methods: a) abrasive-wheel-wear test method, determining the wear resistance and the wear index of anodic oxidation coatings on flat specimens of aluminium and its alloys; b) abrasive jet test method, comparing the resistance to abrasion of anodic oxidation coatings on aluminium and its alloys with that of a standard specimen or, alternatively, a reference specimen, by use of a jet of abrasive particles; c) falling sand abrasion method, determining the abrasion resistance with falling sand applied to thin anodic oxidation coatings.The use of these methods for coatings produced by hard anodizing is described in ISO 10074.