Why does aluminum ductwork require closer hanger spacing than galvanized?

Aluminum has a significantly lower modulus of elasticity than galvanized steel, meaning it is much softer and more prone to bending, sagging, and warping under its own weight or internal air pressure. Hanger spacing must typically be reduced from 10 feet down to 4 to 6 feet max for wide aluminum lines.

['Aluminum has a significantly lower modulus of elasticity than galvanized steel, meaning it is much softer and more prone to bending, sagging, and warping under its own weight or internal air pressure. Hanger spacing must typically be reduced from 10 feet down to 4 to 6 feet max for wide aluminum lines.']

Stop if

• Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

Steps

• Stop and verify the approved detail, manufacturer instructions, foreman direction, and project specs before touching it.
• Aluminum has a significantly lower modulus of elasticity than galvanized steel, meaning it is much softer and more prone to bending, sagging, and warping under its own weight or...

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