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Scope:

This specification covers the galvanized coating applied to general steel articles, structural sections, fabricated steel assemblies and threaded fasteners.

Relevant Standards:

American Society for Testing and Materials (ASTM)

A123 Zinc (Hot Galvanized) Coatings on Products Fabricated from Rolled, Pressed, and Forged Steel Shapes, Plates, Bars and Strip
A143 Safeguarding Against Embrittlement of Hot Dip Galvanized Structural Steel Products and Procedure for Detecting Embrittlement
A153 Zinc Coating (Hot Dip) on Iron and Steel Hardware
A767 Zinc Coated (Galvanized) bars for concrete reinforcement
A780 Repair of Damaged Hot Dip Galvanizing Coatings

 

Products:
  1. Steel members, fabrications, and assemblies shall be galvanized after fabrication by the hot dip process in accordance with ASTM A123 or CSA G164-1981M.
  2. Bolts, nuts, washers and iron and steel hardware components shall be galvanized in accordance with ASTM A153 or CSA G164-1981M.

Coating Requirements:
  1. Weight: The Weight of the galvanized coating shall conform with ASTM A123 or ASTM A153 or CSA G164-1981M (see table below) as appropriate.

  2. Surface Finish: The galvanized coating shall be continuous, adherent, as smooth and evenly distributed as possible and free from any defect that is detrimental to the stated end use of the coated article.

    The integrity of the coating shall be determined by visual inspection and coating thickness measurements.

  3. Adhesion: The galvanized coating shall be sufficiently adherent to withstand normal handling during transport and erection.

Fabrication:

Fabrication practices for products to be galvanized shall be in accordance with the applicable portions of ASTM A 143.A 384 and A 385, except as specified herein. Care shall be taken to avoid fabrication techniques which could cause distortion or embrittlement of the steel. Before fabrication proceeds, the Architect/Engineer shall be notified of potential warpage problems which may require modification in design.

Table 1

Mass of Zinc Coating for Various Classes of Material

Classification of Material Minimum mass of zinc coating g/m² (oz/ft²) Equivalent minimum thickness
µm (mils)
1 Castings iron and steel 550 (1.80) 78 (3.00)
2 Rolled, drawn, pressed, or forged steel articles (except Classifications 3, 4, and 5 listed below)
1 mm (0.039 in) and up to but not including 2 mm (0.078 in) 260 (0.85) 37 (1.44)
2 mm (0.078 in) and up to but not including 3 mm (0.118 in) 400 (1.31) 57 (2.22)
3 mm (0.118 in) and up to but not including 4 mm (0.157 in) 500 (1.64) 71 (2.77)
4 mm (0.157 in) and up to but not including 5 mm (0.196 in) 560 (1.84) 80 (3.13)
5 mm (0.196 in) thick and heavier 610 (2.00) 87 (3.40)
3 Screws, bolts, nuts, rivets, nails, and similar fasteners 10mm (0.394 in) and under in diameter

Washers under 5 mm (0.196 in) thick

260 (0.85) 37 (1.44)
4 Screws, bolts, nuts, rivets, nails, and similar fasteners over 10mm (0.394 in) and up to 12 mm (0.0472 in) diameter

Washers 5 mm (0.196 in) to 6 mm (0.236 in) thick

300 (1.00) 42 (1.64)
5 Bolts, nuts, and threaded fasteners over 12 mm (0.472 in) diameter

Washers over 6 mm (0.236 in) thick

460 (1.50) 65 (2.54)
Notes:
(1) Based upon mathematical calculations, 100 g of zinc per m² of surface corresponds to a coating thickness of 14.3 µm (2 oz/ft² of zinc corresponds to a coating thickness of 3.4 mils)

(2) The mass of coating in this Standard is in terms of grams per square metre of surface area. In the continuous galvanized sheet and strip industry, mass of coating is defined in terms of grams per square metre of sheet, both sides inclusive.

(3) In the case of products galvanized after being assembled from various material classifications listed in Table 1, the coating mass of each class shall be as shown in Table 1.