Which feature is specifically designed to increase rigidity and reduce vibration in rectangular ductwork?

Which feature is specifically designed to increase rigidity and reduce vibration in rectangular ductwork?

• A. Dampers
• B. Return-Air
• C. Air handler
• D. Cross break

Answer: (D)

Rectangular duct panels can flex and vibrate as air moves through them, especially over long runs. Cross breaks are interior folds or ribs that subdivide the wide panel into smaller sections. These stiffening features act like supports, making the duct more rigid and raising its resistance to bending, which reduces vibration and the associated noise. Dampers change how much air flows or how it is distributed, which can influence noise but don’t inherently strengthen the duct itself. Return-air paths and the air handler are system components, not features that stiffen rectangular ductwork. So the feature designed to increase rigidity and reduce vibration is the cross break.

Rectangular duct panels can flex and vibrate as air moves through them, especially over long runs. Cross breaks are interior folds or ribs that subdivide the wide panel into smaller sections. These stiffening features act like supports, making the duct more rigid and raising its resistance to bending, which reduces vibration and the associated noise.

Dampers change how much air flows or how it is distributed, which can influence noise but don’t inherently strengthen the duct itself. Return-air paths and the air handler are system components, not features that stiffen rectangular ductwork. So the feature designed to increase rigidity and reduce vibration is the cross break.