scope:

This International Standard specifies the key factors in the atmospheric corrosion of metals and alloys. These are the time of wetness (T), pollution by sulfur dioxide (SO₂) (P) and air-borne salinity (S). Corrosivity categories (C), which are defined on the basis of these three factors, are used for the classification of atmospheres.

The classification given in this International Standard can be used directly to evaluate the corrosivity of attnospheres for metals and alloys under known conditions of time of wetness, pollution by sulfur dioxide (SO₂)and/or airborne salinity.

This International Standard does not chracterize the corrosivity of specific service atmospheres, e.g. atmospheres in the chemical or metallurgical industries. The pollution and time of wetness characterization of these environments cannot be generalized.

The classified pollution and corrosivity categories can be directly used for technical and economical analyses of corrosion damage and for a rational choice of protection measures.

Annex A summarizes the technical content of this International Standard in an easily read form.