Corrosion classes

Corrosion classes according to the standard PN-EN ISO 12944-2:2001

Corrosion classes		Examples of environments typical of temperate climates (for information only).
Corrosion classes		Inside	Outside
C1	very small	Heated buildings with a clean atmosphere, e.g. offices, shops, schools, hotels.	N/A.
C2	small	Unheated buildings where condensation may occur, e.g. warehouses, sports halls	Atmospheres slightly polluted; mainly rural areas.
C3	medium	Production rooms with high humidity and some air pollution, e.g. food plants, laundries, breweries, dairies.	Urban and industrial atmospheres, medium sulfur oxide (IV) pollution, e.g. coastal areas with low salinity.
C4	large	Chemical plants, swimming pools, ship and boat repair yards.	Industrial areas, coastal areas with medium salinity.
C5-I	very large (industrial)	Buildings or areas with almost constant condensation and heavy pollution.	Industrial areas with high humidity and aggressive atmosphere.
C5-M	very large (sea)	Buildings or areas with almost constant condensation and heavy pollution.	Coastal areas and areas far from the shore into the sea with high salinity.

**Information on determining the corrosion class for stainless and acid-resistant steel products: The classification of stainless steels for use in a given corrosive environment was based on the PN-EN 10088-1-5 standard, which describes the grades of corrosion-resistant stainless steels and on the basis of the characteristic properties of these steels. As a rule, it should be assumed that if chloride ions are present in high concentrations in the product's operating environment, an acid-resistant product (AISI 316L) should be selected. It should also be remembered that regular maintenance of the surface of the elements also contributes to achieving high corrosion resistance. The product is made of stainless steel (AISI 304) or acid-resistant steel (AISI 316L), as a rule, it is not painted. It is possible to paint such products.