Exhaust Fan Backdraft Damper
Exhaust fans need backdraft dampers to prevent reverse airflow when fan is off.
What You Might Be Looking At
damper with blades that close by gravity or spring when exhaust fan stops
Apprentice words: flap on fan, one-way damper, gravity damper, exhaust check valve
Trade terms: backdraft damper, gravity damper, relief damper, exhaust damper
Check First
What Not To Do
Don't install exhaust fans without backdraft dampers where required. Don't use wrong damper type for the application.
What can go wrong: Reverse airflow, odor transfer, energy waste, cold air infiltration, fan damage from wind
Better Foreman Question
For this exhaust fan, is a backdraft damper required? And what type — gravity or spring-loaded?
Verify With
Reference type: project specs, manufacturer install instructions
Source to verify: Exhaust fan manufacturer guide, project exhaust system details
Safe wording: Backdraft damper requirements vary by exhaust type and local code.