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Corrosion
Corrosion
ISO 9223: 2012 has established a classification system for atmospheric corrosion of various environments for alloys and metals. It defines the corrosion classes
of atmospheric, on the corrosion rate detected in environments for one year on standardised specimens. The norm provides dose-response functions for
estimating the corrosivity class, calculated based on normalised metals' annual loss from corrosion. It makes it possible to estimate maximum corrosion class
based on the local environment situation knowledge. These consist of the combined effect of temperature and humidity and pollution from sulfur dioxide and
salinity.
The reference standard does not consider other elements, such as wind speed, sand abrasion, accidental breakage of the protective layer, maintenance
frequency, and exposure level. The classifications in the areas shown do not identify solutions or test methods for their suitability.
The fittings located in or near coastal locations may suffer oxidation caused by the atmospheric conditions; this may affect the finish and appearance of the
luminaire, but not necessarily its electrical integrity.
However, the electrical integrity and safety of the fitting are paramount, which a suitably qualified persons should also check as part of the maintenance cycle.
It is usually recommended that a regular maintenance regime be undertaken in coastal locations. The fittings are frequently hosed down with clean water and a
liquid-based surfactant, which should be used to clean down the salty regularly deposits.
As third parties are involved and responsible for undertaking actions outside our remit, we wish to clarify that we cannot be held accountable for acts of nature
and offer this advice as best practice only.
Note: without prejudice – die-cast aluminium chemically pre-treated polyester powder coated products offer some protection, it is not a
total protection against a marine environment
Corrosivity category for typical external environments
Corrosivity
Category
Corrosivity
Typical environments
C1
Very low
Dry or cold zone, atmospheric environment with very low pollution and humidity time, e.g., certain deserts, Central Arctic / Antarctica.
C2
Low
Low-temperature zone, low pollution atmospheric environment (SO2* <5 μg / m3), rural areas, and small towns. Dry or cold location, atmospheric setting
with a short humidity time, e.g., deserts, subarctic areas.
C3
Medium
The temperate zone, atmospheric environment with medium pollution (SO2*: from 5 μg / m3 to 30 μg / m3) or some chlorides, e.g., urban areas, coastal areas
with low chloride deposition. Subtropical and tropical zone, quiet pollution atmosphere.
C4
High
Temperate zone, highly polluted atmospheric environment (SO2*: 30 μg / m3 to 90 μg / m3) or substantial effect of chlorides, e.g., polluted urban areas,
industrial areas, coastal areas without saltwater splash or exposure to the strong impact of antifreeze salts-subtropical and tropical zone, medium pollution
atmosphere.
C5
Very high
Temperate and subtropical zone, atmospheric environment with very high pollution (SO2*: from 90 μg / m3 to 250 μg / m3) and significant effect of
chlorides, e.g., industrial areas, generic coastal areas, sheltered locations on the coast.
CX
Extreme
Subtropical and tropical zone (very high humidity period), atmospheric environment with very high SO2* pollution (above 250 μg / m3) including
accompanying and production factors and the strong effect of chlorides, e.g., extreme industrial areas, coastal and offshore locations, and occasional contact
with salt spray. Category CX is to be considered for extreme situations where the corrosion rates exceed the upper limits in category C5. Indeed, CX refers to
specific marine and marine/industrial environments, such as bridges.
* SO2*: Sulphur dioxide – (not sodium chloride)
Corrosion
XXVIII
