SNZ AS/NZS 2312.2
Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings Part 2: Hot dip galvanizing
|Publication Date:||19 December 2014|
This Standard provides guidelines and recommendations regarding general principles of design, appropriate for articles to be hot dip galvanized for corrosion protection. The application of zinc coatings by hot dip galvanizing provides an effective method of retarding or preventing corrosion of ferrous materials. Zinc coatings are used in this regard because they protect iron and steel both by barrier action and by galvanic action.
The protection afforded by the zinc coating to the article will depend on the method of application of the coating, the design of the article (both of which directly influence the thickness of the zinc coating), and the specific environment to which the article is exposed. The zinc coated article can be further protected by application of additional coatings, such as organic coatings (paints or powder coatings). When applied to hot dip galvanized articles, this combination of coatings is often known as a 'duplex system'.
This Standard applies to hot dip galvanized coatings applied by the following processes:
(a) Hot dip galvanized coatings, applied after fabrication. (See Clause 5.1.2.)
(b) Hot dip galvanized coatings, applied onto continuous sheet. (See Clause 5.1.3.)
(c) Hot dip galvanized coatings, applied onto continuous cold-formed shapes. (See Clause 5.1.4.)
Other zinc coating processes covered in this Standard are the following:
(i) Mechanically plated coatings (see Clause 5.1.5).
(ii) Electrodeposited coatings (see Clause 5.1.6).
Specific product-related requirements (e.g. for hot dip galvanized coatings on tubes or fasteners, etc.) will take precedence over these general recommendations.