Sheet Metal & Air Conditioning Contractors’ National Association

Papers and Guidelines


These papers are copyrighted by SMACNA. SMACNA grants single user permission to download and use. Any further use in part or in whole requires permission.


Effects of Imposing a Universal Requirement on All Components of Ductwork

This technical paper reviews the HVAC Duct Construction Standards, 2nd edition, 1995, specifications and requirements for zinc coating on galvanized steel ducts. Paragraph and page references from the HVAC-DCS manual are provided along with the text. Commentary in the form of italicized text has been added to clarify the meaning, scope or intent of the manual. In addition the paper reviews zinc coating thickness variations, as commonly used in trade practice, for sheet, reinforcements, tie rods and fasteners. Also included in the paper are the burdensome effects of imposing a universal requirement of G-60 and/or G-90 coating for all components. Wide distribution of this technical paper in the construction community is encouraged.