The durability of hot dip galvanizing is at the core of its many advantages. The average performance of an 85 μm hot dip galvanized coating can give an average maintenance free life of 60 years across the UK and Ireland. The upper band of this can be as high as 170 years.
This is coupled with the fact that the coating is measurable and highly predictable, as zinc dissipates in a linear fashion. So if exact predictions of its ultimate performance need to be made, this is possible after steelwork has been galvanized.
Nondestructive initial coating thickness measurements can be made using thickness gauges. Annual thickness coatings can then be taken at the same points over a period of a few years. This can be used to obtain an annual corrosion rate for the local environment. By dividing this with the initial coating thickness, the performance of the coating in the specific local environment can be calculated. This relationship will hold as long as the environmental conditions remain stable.