The common rating thicknesses for zinc as a coating on galvanized steel are G60 and G20.

• A. True
• B. G60 and G20 are used for other coatings
• C. G60 and G20 indicate copper content
• D. False

Answer: (D)

The numbers on a galvanized coating tell you how thick the zinc layer is, in terms of coating weight per area. In practice, the most common ratings you’ll see for structural galvanized steel are G60 and G90, where higher numbers mean a thicker, more durable coating. G20 is a much thinner coating and isn’t considered a typical, standard pairing for general structural uses. So the statement is not accurate because the common combination is G60 with G90, not G60 and G20.