AS/NZS4600 requires that cold-formed sections must
be adequately protected from corrosion attack. The
protection options range from basic painting through to
heavy galvanised systems.
Before specifying the type of purlin, you need to consider
the type of structure, climatic conditions, the proximity to
salt sprays and maintenance provisions.
The zinc coating and quality-controlled galvanising
process used in GALVASPAN® steel ensure a high
standard of corrosion protection.
The two standards of corrosion protection used in
GALVASPAN® steel are 350g/m² zinc coating weight and
450g/m² zinc coating weight.
The zinc coating weight is the total weight of zinc on the
base steel, and is usually referred to by the coating class, that is 350g/m² of zinc is class Z350. The respective coating classes represent approximate coating thickness of Z350 - 24μm and Z450 - 31μm of zinc on each side of the strip. Z450 purlins should be specified for environments requiring additional corrosion protection.