Fire dampers and smoke dampers are easy to confuse. Both sit inside ductwork, both close to stop fire or smoke spreading through the building, and both need regular testing. But they work in different ways, and they’re tested in different ways too. This guide explains what each one does, how they’re tested and what to keep on record.
What a fire damper does
A fire damper is fitted where a duct passes through a fire-resisting wall or floor. It keeps the fire resistance of that wall or floor intact. Most fire dampers are held open by a fusible link, a small metal link that melts at a set temperature. When it melts, a spring or gravity drops the blade and closes the duct.
Fire dampers are passive. They don’t need power or a signal from the fire alarm. They react to heat in the duct. That makes them simple and reliable, as long as nothing stops the blade from dropping all the way down its guides.
What a smoke damper does
A smoke damper is designed to control the spread of smoke. Smoke dampers are usually motorised and controlled by the fire alarm or a building management system. When the alarm goes off, the damper closes (or, in some smoke control systems, opens) to manage where smoke goes.
Some dampers do both jobs. These combined fire and smoke dampers are motorised, respond to the alarm and also close at a set temperature.
How each is tested
Fire dampers are drop tested. The fusible link or release mechanism is triggered so the blade drops, proving it closes fully. The damper is then reset, and the result is recorded, ideally with photos. See our fire damper testing guide.
Smoke dampers are tested through their controls. The damper is operated by its motor, often by simulating an alarm signal, to check it moves fully and that its position is signalled back correctly. This usually needs coordination with whoever looks after the fire alarm or building controls. We offer smoke damper testing as well as fire damper testing.
Need it done? Duct Doctor cleans and tests kitchen extract and ventilation systems across London and the South East, with a certificate and photo report after every clean. Get a fixed quote.
How often they should be tested
BESA says all fire dampers should be tested by a competent person when they’re installed and at least annually after that, and that spring-operated dampers need annual testing as a minimum (BESA, Fire Damper Testing Requirements). Your fire risk assessment or the building’s fire strategy may set a shorter interval for some dampers, particularly those in demanding environments.
Common faults
- Dust, grease or corrosion stopping the blade from closing fully. BESA highlights all three.
- Damaged or painted fusible links.
- Blades that stick or springs that have weakened.
- No access panel, so the damper can’t be reached or tested.
- Motor or wiring faults on smoke dampers.
Dampers in kitchen extract ducts are especially at risk from grease. Failed dampers should be repaired or replaced. Duct Doctor carries out fire damper repairs on dampers that fail testing.
Who is responsible
BESA notes that the responsible person, whether that’s the employer, owner, landlord, facilities manager or managing agent, has a legal duty to keep fire safety systems, including dampers, working. Keep a register of every damper, its location, type and test history, so nothing is missed. See the responsible person under the Fire Safety Order.
Quick answers
Are fire and smoke dampers the same thing?
No. Fire dampers react to heat. Smoke dampers are usually motorised and controlled by the fire alarm. Some dampers do both.
How often should fire dampers be tested?
BESA says at least annually, and on completion of installation.
What happens if a damper fails its test?
It’s recorded and should be repaired or replaced as soon as possible.
Related services
More advice
- Fire Damper Testing: A Guide for Building Owners
- The Responsible Person Under the Fire Safety Order
- Duct Access Panels: Why They Matter for TR19
- Hotel Kitchen Ventilation and Extract Cleaning
- All advice
This guide is general information. It isn’t legal or insurance advice: check your own policy wording and lease, and speak to a qualified adviser about your fire risk assessment.