| Corrosion class | C1 | C2 | C3 | C4 | C5 | CX | |
| Environmental corrosion | Very low | Low | Average | High | Very high | Extreme | |
| Examples of environments | Indoors | Heated areas with arid atmosphere and insignificant quantities of pollutant, e.g. offices, shops, schools and hotels. | Non-heated areas with fluctuating levels of temperature and humidity. Few instances of condensation and low levels of airborne pollution, e.g. sports halls and warehouses. | Average levels of humidity and some airborne pollution resulting from production processes, e.g. breweries, dairies, laundries. | High humidity and considerable airborne pollution as the result of production processes, e.g. chemical plants, swimming pools and dockyards. | Buildings with almost permanent condensation and with high pollution | Industrial buildings with extreme humidity and aggressive atmosphere. |
| Outdoors | Atmospheres with low levels of airborne pollution. Rural areas. | Atmospheres containing some salt or average levels of air-borne pollution. Urban and light industrial areas. Areas affected by coastal conditions. | Atmospheres with average salt content or discernible levels of airborne pollution. Industrial and coastal areas. | Industrial areas with high humidity and aggressive atmosphere, and coastal areas with high salinity | Offshore areas with high salinity, industrial areas with extreme humidity, and aggressive atmospheres, sub-tropical or tropical atmospheres. | ||
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Wibe Group designation
Exceeds requirements. Extremely high durability.
Recommended very high durability ( >20 years)
Possible alternative. High durability (10-20 years) |
Electro-galvanized (EG) |
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| Pre-galvanized (PG) |
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| Zinc+ (Z+) |
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| Hot-dip galvanized (HDG) |
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| Zinkpox (ZP) |
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| Stainless steel AISI 304L(SS304) |
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| Stainless steel AISI 316L (SS316) |
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| Glass Fibre Reinforced Polymer (FRP/GRP) |
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This table shows estimated values.
For more detailed advice, please contact technical support at Wibe Group