Paint Corrosivity

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Description

According to ISO 12944-2 Corrosivity Classes with Environmental Examples

Corrosivity Class

Environmental

Corrosivity

Examples of typical environments (informative)

 

 

 

Outdoors

Indoors

C1

Very Low

 

Heated spaces with dry air and insignificant amounts of pollutants, for example offices, stores, schools and hotels.

C2

Low

Atmospheres with low levels of pollution. Rural areas

Non-heated areas with fluctuating temperature and humidity. Low frequency of moisture condensation and low content of impurities, such as sports halls and warehouses.

C3

Moderate

Atmospheres with some salt or moderate air pollution. Urban and light industrial areas. Areas with some influence from the coast.

Areas with moderate humidity and a certain amount of air pollution from production processes, such as breweries, dairies and laundries.

C4

High

Atmosphere with a moderate amount of salt or significant amounts of air pollution. Industrial and coastal areas.

Areas with moderate humidity and a certain amount of air pollution from production processes, such as chemical plants, swimming pools and shipyards

C5 - I

Very High (Industrial)

Industrial areas with high humidity and aggressive atmosphere.

Areas with almost permanent condensation and high levels of air pollution

C5 - M

Very High (Maritime)

Coastal and offshore areas with high salinity.

Areas with almost permanent condensation and high levels of air pollution


Environmental factors which affect the useful life of Lindab Colour Coated paint coat: 

  • ​Exposure to salt water
  • Industrial emissions
  • Traffic emissions
  • Oil-fired plant emissions

​​Sun affects

​Ultraviolet radiation accelerates aging of the paint coating and it also heats the paint. Light colours will last longer than dark colours as the sun has an effect on the useful life.

A shallow pitched roof facing south is affected more seriously than north-facing surfaces by the sun.

How to treat corrosion damage on sheet metal

  1. ​Scrape, sand or sand blast off any loose organic material.
  2. Remove any rust through sandblasting or by sanding the sheet metal completely clean in the damaged area.
  3. Clean with alkaline degreaser, for example 5% caustic soda with the addition of a little detergent. Carefully rinse the surface with water and allow to dry.
  4. Paint with a zinc-rich undercoat.
  5. Apply a suitable paint over this.​