Corrosion protection in offshore and wind turbine industry
When steel must last decades under salt water and hard weather
Some surface treatment specialists find their specialty in the environments where corrosion protection requirements are the highest: offshore structures, port facilities and wind turbines. Here the steel must last for decades under constant salt exposure, UV radiation and changing weather – and failure in protection can be expensive to fix once the structure stands far out to sea.
§ISO 12944 – language for corrosion environments
The standard ISO 12944 divides atmospheric environments into corrosivity categories from C1 to C5, plus an extreme category CX for, among other things, offshore environments and direct saltwater contact. The higher the category, the more powerful a coating system is typically required.
| Category | Environment | Example |
|---|---|---|
| C1 | Very low corrosivity | Heated, dry indoor spaces such as offices |
| C2 | Lav korrosivitet | Rural areas, unheated rooms with low condensation risk |
| C3 | Moderate corrosivity | Urban and industrial environments or coastal areas with low salt content |
| C4 | High corrosivity | Industrial zones or coastal areas with moderate salt content such as ports |
| C5 | Very high corrosivity | Heavily polluted industrial zones or coastal areas with high salt content |
| CX | Extreme corrosivity | Offshore areas and direct saltwater contact |
§Im-categories — when the steel is submerged
Beyond the atmospheric categories, ISO 12944 operates with Im categories for immersion: Im1 for steel in fresh water, Im2 for steel immersed in salt or brackish water — for example sluice gates and offshore foundations — and Im3 for steel in soil, such as sheet piles, buried tanks and pipelines.
§Multi-layer systems last longer than one layer
In the high corrosion categories it is the norm to build the coating system up from several layers each with its own function: a zinc-rich primer that provides sacrificial galvanic protection like galvanizing an epoxy intermediate layer that functions as a thick tight barrier and a polyurethane topcoat (PUR) that provides UV and weather resistance so the underlying system is not broken down by sunlight and weather.
§Wind turbines — a growing Danish specialty
The expansion of green energy especially offshore wind increases demand for surface treatment specialists with experience in corrosion protection. Wind turbine towers and foundations must be painted or coated to last for decades under sustained salt exposure and changing temperatures and there is ongoing need for inspection and maintenance of the protection already on the structures.
Corrosion protection in these environments is therefore both a technical and physical discipline — but for those who become skilled at it, it is a specialty with good demand and long, exciting jobs.