Time to First Maintenance years 10 0 0 10 20 30 40 50 60 70 80 90 1 5 5 0 4 5 4 0 3 0 2 5 2 0 1 5 0 Rural Suburban Temperate Marine Tropical M a rine Industria l K e y Average Thickness of Zinc mils 3 Time to first maintenance is defined as the time to 5 rusting of the steel surface 1 mil 254m 056ozft 2 HDG coatings have a foreseeable servicelife Coating servicelife is foreseeable as long as climate conditions in which the coatings are exposed are known T he ASTM has published the results of a research conducted in different environments where zinc coatings could be exposed to a v ariety of climate conditions 13