The Corrosivity Categories
ISO 12944 is a globally recognised standard that provides guidelines on the protection of assets from corrosion. It covers the protective paint systems designed for application to abrasive blasted steel, hot dipped galvanised steel and thermally sprayed zinc steel.
The classification of the environment is given as per table:
Corrosivity Category | Application Area – Outdoors | Application Area – Indoors |
C1 (Very low) | Not Applicable | Inside heated rooms – offices, commercial buildings, schools, hotels |
C2 (Low) | Low pollution, mostly rural areas | Unheated buildings where condensation may occur – storage, facilities, sport centres |
C3 (Medium) | Urban and industrial areas, moderate pollution, coastal regions with low salt concentration | High humidity rooms with some air pollution – breweries, dairies, food production facilities |
| C4 (High) | Industrial areas, coastal regions with moderate salt concentration | Chemical plants, swimming pool, boat houses above sea water |
C5 – I (Very high) | Industrial areas with high humidity and aggressive atmospheres | Building and areas with ever present condensation and heavy pollution |
| C5 – M (Maritime) | Coastal and offshore regions with high salt concentration | Buildings and areas with ever present condensation and heavy pollution |
The durability categories of corrosion protection are as follow:
Low | Medium | High | Very High |
| Up to 7 years | 7-15 years | 15-25 years | More than 25 years |
To find out more information, please contact Exnovo’s team of experts to discuss the best surface protection for your transformer needs.
