Hot Dip Galvanizing has the lowest first cost than many other commonly specified protective coatings for steel. (The application cost of labour intensive coatings such as painting has risen far more than the cost of factory operations such as hot dip galvanizing).

Even in cases where the initial cost of galvanizing is higher than alternative coatings, hot dip galvanizing is almost invariably cheapest in the long term (because it lasts longer and needs less maintenance). Also, maintenance causes problems and adds to costs when structures are located in remote areas, and when plant shutdown or disruption to production is involved.

Acid pickling is part of the process, so ensuring a good final coating. Organic coatings should be applied over a suitably prepared surface (generally SABS 8501-1:1988 to SA 2½) normally verified by third party inspection. Additionally, the application of organic coatings is limited in terms of ambient conditions of temperature and humidity. Therefore first cost of organic coatings is increased.

A full protective coating can be applied in minutes; a 4-coat paint system requires a week. The galvanizing process is not dependent on weather conditions.

Galvanized coatings are assessed readily by eye, and simple non-destructive thickness testing methods can be used. Inspection of organic coatings is required after preparation and each stage of coating application to ensure good quality. The galvanizing process is such that if coatings appear sound and continuous, they are sound and continuous.

Every part of a galvanized article is protected, even recesses, sharp corners and inaccessible areas. The coating is as thick over sharp corners and edges as on flat surfaces. Thickness, coating adhesion and uniformity are features of the process. No coating applied to a structure or fabrication after completion can provide the same protection.

Galvanized coatings corrode preferentially to steel, providing cathodic or sacrificial protection to small areas of steel exposed through damage. Unlike organic coatings, small damaged areas need no touch up.

A galvanized coating has a unique metallurgical structure which gives outstanding resistance to mechanical damage in transport, erection and service.

Galvanizing is carried out to SANS121 (ISO1461) and standard, minimum coating thicknesses (55um) are applied (see spec). Coating life and performance are reliable and predictable.

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