Hot-dip galvanised steel has been effectively used for more than 150 years. The value of hot-dip galvanising stems from the relative corrosion resistance of zinc, which, under most service conditions is considerably better than those of iron and steel. In addition to forming a physical barrier against corrosion, zinc applied as a hot-dip galvanised coating protects exposed steel. Furthermore, galvanising for protection of iron and steel is favoured because of its low cost, ease of application, and the extended maintenance-free service that it can provide.
Below is an indication as to the “life to first maintenance” for galvanised steel, because very few real-life situations are as pure as the headings in the table would suggest, this tabulation is a significant over-simplification. Nevertheless, it does provide a useful guide. Many environments can be a combination of two or more of those shown. Furthermore, locally extreme conditions may exist, which could have a severely adverse effect on the performance of the zinc. In these instances further protection with a recommended paint is recommended.
Note 1: The recommendations for period to first maintenance are based on the premise that the strength and integrity of the sheet would diminish after the period specified, unless maintenance was carried out.
Note 2: Minimum average triple spot (including both surfaces).
Note 3: Further protection with a suitable paint is essential for this kind of application.
Note 4: The periods shown are based on theoretical weight loss as a result of natural weathering under test conditions.
PSP stock a range of galvanised sheets in various thicknesses ranging from 1mm to 3mm, and a variety of sheet sizes from 1000 x 3000mm to 1250 x 4000mm. 4000mm to 6000mm lengths is available upon request.