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).