ISO 12944-5:2018 describes the types of paint and paint system commonly used for corrosion protection of steel structures. ISO 12944-5:2018 also gives guidelines for the selection of paint systems available for different environments (see ISO 12944-2) except for corrosivity category CX and category Im4 as defined in ISO 12944-2 and different surface preparation grades (see ISO 12944-4), and the durability grade to be expected (see ISO 12944-1).