IPS-E-TP-100-8.4.9 Metal plus paint system
Metal-Coated steel is painted only when:
a) the environment is very acidic or very alkaline (i.e. when pH Value is outside the range 5-12
for zinc or 4 to 9 for aluminum); or,
b) the metal is subject to direct attack by specific chemicals (see Note under 184.108.40.206); or,
c) the required decorative finish can be obtained only by paint; or,
d) when additional abrasion resistance is required.
The thickness of the paint is related to the type of environment, generally one or two coats of paint
(dry film thickness, 100 microns) may be sufficient except in abnormally aggressive environments
(like acid environment). Sealed sprayed metal is usually preferable to painted sprayed metal.
Appropriate paints usually have a longer life on metal coating than on bare steel, and rusting and
pitting of the steel is reduced or prevented.