Corrosion handbook

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In Table 6 the environmental conditions given in the tables are described in more
detail. The underlying predominant corrosion categories and corrosion resistance
classes are also listed.
Corrosion categories according to ISO 9223:2012 Corrosion resistance class Stainless steel
Indoor applications
Dry indoor environments
(heated or air-conditioned areas) without condensation, e.g.
office buildings, schools
C1, C2 1
Indoor environments with temporary condensation
(unheated areas without pollutants), e.g. storage sheds
C1, C2 1
Outdoor applications
Outdoor, rural or urban environment with
low pollution
Large distance (> 10 km) from the sea
C2,C3 2
Outdoor, rural or urban environment with moderate
concentration of pollutants and/or salt from sea water
Distance from the sea 1-10 km
C2,C3,C4 2,3
Coastal areas
Distance from the sea < 1 km
C3, C4,
C5, CX
3,4
Outdoor, areas with heavy industrial pollution
Atmospheric SO
2 concentration > 10 μg/m3 as yearly
average (e.g. petrochemical, coal industry)
C4,C5,CX 3,4
Close proximity to roadways treated with de-icing salts
Distance from roadways < 10 m C3, C4, C5 3,4
Special applications
Special applications
Areas with special corrosive conditions, e.g. road tunnels
with de-icing salt, indoor swimming pools, special
applications in the chemical industry (exceptions possible).
Special
climates
not
covered by
C-classes
4,5
Table 6: Environmental conditions and their link to corrosivity categories and
corrosion resistance classes, per ISO 9223:2012.