Very low corrosion risk. Indoors with humidity below 60%.
Slight risk of corrosion. Items for use indoors, in unheated and ventilated rooms.
Medium corrosion risk. Items for use indoors, at changing temperatures and humidity. Items for outdoor use in climates far from the sea and industry.
High risk of corrosion. Items for use in densely populated areas and in connection with industrial areas. Above water and at shores.
Very high corrosion risk. Items in constantly humid climate as well as by and in heavy duty industry.