Expected Service Life
The graph below is a plot of the thickness of the galvanized coating against the expected service life of the galvanized coating under outdoor exposure conditions. Most galvanized applications are a minimum of 4 mils of thickness per surface.
The expected service life is defined as the life until 5% of the surface is showing iron oxide (rust). At this stage, it is unlikely that the underlying steel or iron has been weakened or that the integrity of the structures protected by the galvanized coating have been compromised by corrosion.