Some factors effecting the selection of zinc coatings for building components Available to Purchase

Zinc coatings to combat corrosion in a wide range of structural steelwork and general metalwork are specified in the Greater London Council's (G.L.C.) Preambles to Bills of Quantities. Typical applications are on dustbins, children's playground equipment, structural sections and building components. Hot dip galvanising is generally preferred for protecting structural steel and ferrous metalwork in aggressive conditions or inaccessible places. The galvanised metal must comply with BS 729: 1971; after fabrication it is coated in one operation by complete immersion in the zinc bath and all excess is removed. The finished surface should be clean and uniform. Zinc coatings to BS 2989: 1982 are used for interior applications where it is normally dry. Zinc spray to BS 2569: Part 1: 1964 is specified where the size of members prohibits hot dip galvanising. Zinc coatings may be covered with paint or plastic coatings to provide additional protection and improve appearance. Designers are advised to consult BS 5493: 1977 or DD 24: 1973 for guidance on how to specify protective systems.