For 70 years, the science and real-world experience was clear: greater corrosion resistance was best achieved by coating the chosen metal with a weightier layer of zinc. In many cases, studies went so far as to suggest that the relationship between corrosion resistance and the amount of zinc coating was linear; if a company doubled the weight of the zinc layer, they could double the life of the material before the appearance of red rust. Some additional time could be bought for galvanized metal with chemical treatments and other passivations, but if further protection was needed or desired, zinc was the only viable option for additional rust protection. Before InterCoat®ChemGuard was introduced to the market, that is.
To protect manufacturers, assure end users and standardize uniform conditions of rust protection expectations, updated specifications are required. Having concrete, standardized specifications takes the guesswork out of what rust protection processes should be used under certain conditions. As a necessary tool in this field of work, these specifications are not just guidelines. They represent a standard industry minimum that allows industry professionals to mathematically predict the approximate life for galvanized products while providing their customers with reasonable expectations.
If the assumptions based on outdated methods are no longer valid, if the previously-assumed linear relationship between zinc weight and rust protection has been superseded by new technology, industry specifications will have to be rethought, recalibrated and rewritten. A simple fix would be to add “or equivalent” as a two-word amendment to industry specifications; such additional wording would cover new technologies like InterCoat®ChemGuard and prevent the need for additional modifications in the future.
If the focus shifts from zinc coating weight to life expectancy of the product, this seems a natural step. When other, more effective options are available, there’s no need to specify more zinc than is actually required.