In harsh environments the lifetime of electronic equipment is reduced due to the corrosiveness of the atmospheric environment. To
increase the lifetime of the PCB’s, they can be conformal coated according to IEC 61721-3-3. There are not many US standards available
on the levels of conformal coating so we comply with the more difficult IEC standards from the European Union.
There are three classes of coating according to the above mentioned IEC standard:
• Class 3C1: Applies to rural and urban areas with low industrial activities and moderate traffic. Be aware of that salt mist may be
present in sheltered locations of coastal areas
• Class 3C2: Applies to locations with normal levels of contaminants, experienced in urban areas with industrial activities
scattered over the whole area, or with heavy traffic.
• Class 3C3: Applies to locations in the immediate neighborhood of industrial sources with chemical emissions.
The corrosive levels are listed below: