g/m2

g/m2 (grams per square metre) is the standard unit of measure used internationally and within Indian standards (like IS 4736) to quantify the thickness and amount of zinc coating applied during the galvanizing of tubes and pipes.

Significance in Galvanizing

This unit represents the mass of zinc (in grams) deposited over one square metre of the steel surface area. It is the most reliable metric for two critical reasons:

Direct Correlation to Service Life: The longevity of a galvanized pipe—how long it resists corrosion—is directly proportional to the amount of sacrificial zinc present. By specifying a minimum mass in g/m2, the standard ensures the pipe has a guaranteed minimum reserve of zinc for corrosion protection.

Conversion to Thickness: While coating thickness is often cited in micrometres, g/m2 is the preferred regulatory unit because it accounts for the actual material volume. Due to the known density of zinc, g/m2 is easily converted to thickness. For instance, a coating mass of approximately 710 g/m2 typically corresponds to a minimum average thickness of 100 micrometres.