Standardised Typology

In the 1970s, in order to facilitate the comparison of results, corrosion experts started to calibrate their outdoor testing stations on the basis of measurements taken on identical specimens of several metals and alloys such as steel, zinc, copper and aluminium. They were exposed in each participating testing station. These stations were thus classified based on their aggressiveness and the results compared. 

Another approach consists of establishing a link between the level of aggressiveness of a station, and more generally of a zone, and several meteorological criteria as well as 

Type of atmosphere General characteristics Rank of increasing aggressiveness 

Rural Low level of pollution. Inorganic dust CaS04, CaCOs, along with dust of plant origin 1 

Tropical Low level of pollution, or no pollution at all. Very high level of relative humidity, 80% or more 2 

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