When installing an exhaust duct for a downflow domestic range hood, which component is required?

When installing an exhaust duct for a downflow domestic range hood, which component is required?

• A. Backdraft Damper
• B. Fire Dampers
• C. Duct Cap
• D. Noise Silencer

Answer: (A)

A backdraft damper is needed because it acts as a one-way valve in the exhaust duct, letting air flow out only when the hood is on and preventing outside air from being drawn back into the kitchen when the hood is off. This protects against drafts, odors, and energy loss in a downflow domestic range hood where the duct vents to the outdoors. Fire dampers are used where ducts pass through fire-rated protections and aren’t a standard requirement for typical residential hood installations. A duct cap is an exterior termination cover, not the device that controls backflow. A noise silencer reduces sound and is optional, not a mandatory component for proper venting.

A backdraft damper is needed because it acts as a one-way valve in the exhaust duct, letting air flow out only when the hood is on and preventing outside air from being drawn back into the kitchen when the hood is off. This protects against drafts, odors, and energy loss in a downflow domestic range hood where the duct vents to the outdoors.

Fire dampers are used where ducts pass through fire-rated protections and aren’t a standard requirement for typical residential hood installations. A duct cap is an exterior termination cover, not the device that controls backflow. A noise silencer reduces sound and is optional, not a mandatory component for proper venting.