There are a number of specifications that have been developed over the years for hot-dip galvanizing in order to produce a high-quality coating. The most common specifications used in North America are ASTM specifications. However, some design engineers and/or fabricators will call out international or other specifications published by independent organizations, such as AASHTO.

How to Obtain & Update HDG Standards (Specifications)

There are three main governing ASTM specifications for hot-dip galvanized steel:

• ASTM A123/A123M: Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products
  • Single pieces of steel or fabrications with different types of steel products
• ASTM A153/A153M: Standard Specification for Zinc Coating (Hot-Dip) on Iron and Hardware
  • Fasteners and small products that are centrifuged after galvanizing to remove excess zinc
• ASTM A767/A767M: Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement
  • Reinforcing steel or rebar

Additionally, there are several important supporting specifications all design engineers, fabricators, and steel detailers should familiarize themselves with, as they pertain to design best practices, steel selection, and other important topics. The following pages will provide more detail on all of these specifications.

For a further explanation of the above standards:

• Overview of ASTM A767/ A767M Appendixes
• ASTM A123 vs. ISO 1461
• ASTM A123 vs. CSA G164
• ASTM A123 vs. A53
• ASTM A153 vs. ASTM F2329
• Continuous Sheet Galvanizing (ASTM A653 G60, G90) vs. Batch Hot-dip Galvanizing (A123)