For ductwork less than 18 inches wide, hangers are usually made from which material?

• A. 1-inch strips cut from 22-gauge galvanized iron
• B. 2-inch strips cut from 18-gauge steel
• C. 1/2-inch strips of aluminum
• D. Flat metal straps riveted to the duct

Answer: (A)

For ductwork under 18 inches wide, hangers are kept lightweight and corrosion-resistant, using a material that provides enough strength without adding unnecessary bulk. A 1-inch wide strip cut from 22-gauge galvanized iron hits the right balance: it’s thin enough to minimize weight and obstruction, yet sturdy enough to support the duct, and the galvanizing protects against rust in the humid environment typical of HVAC installations. Using a wider, thicker strip would add unnecessary weight and cost, aluminum strips lack the standard galvanic protection and may not be as economical or compatible with common fasteners, and riveted flat straps attached directly to the duct can damage the duct surface and isn’t the usual method for these small ducts.