New galvanized products should be handled, transported and stored with the normal care given to any other surface finished building material. New galvanized steel surfaces which have not yet developed the protective patina are highly reactive and susceptible to premature corrosion under poor conditions of exposure.
Transport should be under dry, well ventilated conditions. When stored on site, material should be covered where possible and raised clear off the ground on dunnage or spacers. When shelter is not possible, material should be stacked to allow drainage of rainwater. Storage in contact with cinders, clinkers, unseasoned timber, mud or clay will lead to surface staining and in severe cases, premature corrosion.
Clearance for ventilation between stacked galvanized products is necessary under damp or humid conditions to avoid the possible development of wet storage stain, a bulky white corrosion product. Attack of the galvanized coating which produces the white corrosion is caused by the retention of water (e.g. condensation or run-off) between the contacting surfaces under conditions of restricted air circulation. The attack is frequently superficial despite the relative bulkiness of the corrosion product, but may be objectionable because of its appearance. In severe cases, corrosion product should be removed to allow the natural formation of a protective zinc carbonate patina.
During the quenching process after galvanizing, a simple chromate conversation coating is formed on the galvanized surface which will minimise the occurance of wet storage stain. If the finished product needs to be free of chromates, air cooling should be specified. Under severe conditions, the chromate coating should not be relied on and new galvanized products should be packed carefully as well as protected for shipment and storage.
Hot dip galvanized coatings can withstand chains used during transport, although straps are preferred for thicker coatings which are usually more susceptible to damage.
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