BENEFITS
When iron is extracted from its ore, a fundamental tendency of nature is abruptly reversed. Unless protected, iron and steel will corrode in most environments, slowly returning to their natural state.
Corrosion prevention is an essential factor in the economic utilisation of steel. Provision of the appropriate protective coating can bring initial savings plus substantia! economies in service, due to reduction or elimination of maintenance and lost service time, and by deferring the replacement date of structures and equipment.
Galvanizing is the best solution for corrosion protection, offering significantly greater benefits than paint or any other coating system. In fact, when it comes to handling, durability, coating thickness, application and protection, there’s no comparison.
Architects and Engineers specify galvanizing because it’s the most effective corrosion system with a long, maintenance-free lifespan. And if you’re considering galvanizing, you might want to review the following major, measurable benefits:
| Long life Well-documented years of experience have proved the benefits of hot dip galvanized protection. At least 10-20 years are commonplace in industrial and marine environments, more than 25 years (frequently much more) in rural atmospheres. When maintenance eventually becomes necessary, it is straightforward: no complex preparation treatments are necessary. |
| Competitive first cost For many applications the cost of galvanizing is lower than that of applying alternative coatings. Furthermore, galvanizing has been getting steadily cheaper compared with painting. The reason is simple: alternatives – particularly painting – are very labour intensive compared with galvanizing which is a highly mechanized, closely controlled factory process. |
| Lowest lifetime cost Low initial cost and long life make galvanizing the most versatile and economic way of protecting steel for long periods (20+ years). There are bonuses from no maintenance or extended maintenance intervals: fewer problems of access in remote areas, difficult terrain or when buildings are closely packed together; also when there are safety restrictions e.g. electricity pylons. |
| Reliability The process is relatively simple, straightforward and closely controlled. The thicknesses (weights) of coatings formed are regular, predictable and simply specified. Galvanizing is one of the few coatings which is completely defined by a British Standard (BS EN ISO 1461). |
| Speed of application A full protection coating can be applied in hours; a complicated paint system can require a week. |
| Coating toughness Galvanizing is unique: the hot dip process produces a coating which is bonded metallurgically to the steel. No other coating process has this feature, and as a result galvanized steel has by far the greatest resistance to mechanical damage during handling, storage, transport and erection – an important factor where steelwork is to be shipped around the world. |
| Complete coverage Because it is formed by dipping steel in molten zinc, all parts of the surface of the steel are coated – inside, outside, awkward corners, and narrow gaps which would be impossible to protect in any other way. The coating actually tends to build up at vital corners and edges – rather than thinning out as do brushed, sprayed and other dipped coatings. |
| Three-way protection Galvanized coatings protect steel in three ways.
Cathodic (sacrificial) protection
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Coating thickness: μm measured from steel surface
1. Steel of >6mm section hot dip galvanized to EN ISO 1461
2. Thick hot galvanized coating
3. Centrifuge galvanizing to BS 7371 Pt.6
4. Zinc spaying toEN ISO 2063
5. Continuous galvanized sheet to EN 10346
6. Zinc plating to Fe/Zn5 of EN 12329
7. Sherardizing to grade 1 of BS 4921
8. Paint and coatings incorporazing zinc dust
Zinc coating compared in terms of coating thickness
| Ease of inspection Galvanized steel simplifies inspection of the protective finish. The nature of the process is such that if the coating looks continuous and sound, it is! Thicknesses – simply specified through BS EN ISO 1461 – can be easily checked with an electronic probe. |
| Faster construction Galvanized steel is ready for use. No further site surface preparation, painting, touch up or inspection is necessary. Once erected the galvanized steel is ready for use: and cladding can begin immediately, thus accelerating the construction programme |
| Versatile Usage Galvanizing provides an attractive finish and offers a superior foundation for a decorative topcoat. |
| Aesthetic Design Galvanizing provides an attractive finish and offers a superior foundation for a decorative topcoat. |
| Environmental Sustainability Zinc, like steel, is a natural substance that is recyclable. |
| Duplex coatings of galvanising-plus-paint are often the most economical solution to the problem of protecting steel in highly corrosive environments. Such systems provide a synergistic effect in which the life of the combined coatings exceeds the total life of the two coatings if they were used alone. |