ASTM International has announced ASTM A90 / A90M - 11 standard test method for weight [mass] of coating on iron and steel articles with zinc or zinc alloy coatings.

This test method provides a standard method for determining the weight [mass] of coating for comparison with specification requirements. A coating of zinc on iron or steel articles provides protection against corrosion. As the protection is provided by sacrificial loss of zinc, the degree of protection is proportional to the weight [mass] of zinc coating. Specifications for zinc-coated articles frequently provide for different classes of coating so that the purchaser can select the coating weight [mass] most suitable to his needs.

This test method covers procedures for determining the weight [mass] of coating on iron or steel sheet, wire, and other articles in which the coating is zinc or a zinc alloy, such as zinc 5 % aluminum (including zinc 5 % aluminum mischmetal and zinc 5 % aluminum 0.1 % magnesium), zinc aluminum magnesium (including zinc 5 to 9 % aluminum magnesium and zinc 9 to 13 % aluminum magnesium) or 55 % aluminum zinc. In the body of this test method, reference to zinc coating shall be interpreted to also include zinc alloy coating except where specifically stated otherwise.

The final results determined by this test method shall be expressed in inch pound units or SI units, depending on the units used in the material specification to which the results are to be compared. Certain portions of the procedure involving determination of specimen weight [mass] have traditionally been performed in SI units, and corresponding inch-pound units are not included.

For sheet products, the final results are expressed as either coating weight [mass] total both sides, or coating weight [mass] separately on each side, depending on the specified requirements.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

(Sourced from ASTM International)