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Ductwork - fire dampers
A fire damper spends years doing nothing, waiting for the one moment it matters. That is exactly why it has to be tested - a device that only acts in a fire, and is never used in between, is a device you cannot assume still works.
The short answer
Recognised guidance, including BS 9999, points to fire dampers being tested at least once every twelve months by a competent person as part of planned maintenance, with more frequent testing where the ductwork is dust-laden or polluted - which includes grease-laden kitchen extract. The check is the drop test, confirming the damper closes fully and seals. This sits under the Regulatory Reform (Fire Safety) Order 2005, which requires the responsible person to keep fire safety provisions in working order.
What they do
Ductwork runs through a building, passing through walls and floors that are meant to be fire barriers. That creates a problem: a duct is a ready-made path for fire and smoke to travel from one compartment to another, straight through the barriers the building relies on to contain a fire. Fire dampers are the answer. Set where ducts cross fire-resisting walls and floors, they are held open in normal use and close automatically in a fire, sealing the duct and restoring the barrier the ductwork would otherwise breach.
So a fire damper is a small, normally-invisible device doing a critical job: keeping a fire from using the ventilation system as a route through the building. It preserves the compartmentation that gives people time to escape and firefighters a chance to control the fire. When it works, it is one of the things that stops a contained fire becoming a spreading one - and because it only acts in that emergency, whether it still works is not something anyone finds out in normal use.
Why testing
The defining feature of a fire damper is that it does nothing until there is a fire. A spring-operated damper is held open, and only releases and drops closed when a fire triggers it. That means it can seize, be painted over, be obstructed by debris, or have its mechanism corrode or clog - and none of it shows in day-to-day operation, because the damper is simply sitting there open as it always is. The failure is silent, and the moment it is discovered is the worst possible one: during a fire.
Testing is the only way to know a fire damper will actually work. Because it is never exercised in normal use, it has to be deliberately operated to prove it still closes and seals - which is exactly what a test does. This is why fire dampers, like other safety devices that only act in an emergency, are on a regular test cycle: not because they are used and wear out, but because they are not used and can fail unnoticed. The test substitutes for the operation the damper never otherwise gets.
How often
The recognised position, reflected in BS 9999, is that fire dampers should be tested by a competent person on completion of installation and thereafter at least once every twelve months as part of a planned maintenance programme. Annual testing is the baseline for a normal system. This all sits under the Regulatory Reform (Fire Safety) Order 2005, which places a duty on the responsible person to ensure fire safety provisions - fire dampers included - are maintained in efficient working order.
Crucially, the twelve-month baseline increases where the environment fouls the dampers faster. Guidance specifically notes that dampers in dust-laden or polluted atmospheres should be tested more frequently, at intervals suited to the degree of pollution - and grease-laden kitchen extract is exactly such an environment. Grease building up around a damper can clog or obstruct its mechanism, making it more likely to fail to close, so a damper in a kitchen extract system may well warrant testing more often than the annual minimum that suffices for cleaner ductwork.
The test
The core of fire damper testing is the drop test. The damper is released and operated to confirm the blade actually closes fully and seats properly within its frame, sealing the duct as it would in a fire. A damper that closes only partway, or does not seal, would not restore the fire barrier and has failed the test. The drop test is the direct proof that the damper does the one thing it exists to do - close the duct against fire and smoke.
Around the drop test, competent testing also inspects the damper's condition - checking for corrosion, obstruction, grease build-up or damage, and confirming the mechanism and any fusible link or actuator are sound - and records the result, with any dampers that failed identified for repair. In a grease-laden extract, that inspection often overlaps with the cleaning, since grease is a common cause of a damper failing to operate. A test that finds a seized or grease-clogged damper has done its job: it has revealed a silent failure before a fire could.
The takeaway
Fire dampers should be tested by a competent person at least every twelve months, and more often where the ductwork is dust or grease-laden - a kitchen extract being a clear case. The reason is the nature of the device: it does nothing until a fire, so it can fail silently, and only a deliberate drop test proves it still closes and seals. The duty to keep it working sits with the responsible person under the fire safety order.
For a building with ductwork crossing fire barriers, that makes fire damper testing part of the fire-safety regime, not an optional extra - and for a kitchen extract in particular, the grease environment is a reason to test more, not less. A tested damper is one you know will act; an untested one is a barrier you are only assuming is there. Regular drop testing turns that assumption into knowledge, before the fire that would otherwise reveal the truth.
Questions
Recognised guidance including BS 9999 points to testing at least once every twelve months by a competent person as part of planned maintenance - and more frequently where ductwork is dust or grease-laden, such as kitchen extract.
The core of fire damper testing - the damper is released and operated to confirm the blade closes fully and seals within its frame, as it would in a fire. A damper that closes only partway or does not seal has failed the test.
Because they do nothing until a fire, so they can seize, be painted over, be obstructed or corrode with no sign in normal use. The failure is silent, and a deliberate test is the only way to know the damper will actually close when needed.
Often yes. Guidance says dampers in dust-laden or polluted atmospheres should be tested more frequently, and grease-laden kitchen extract is such an environment - grease can clog the mechanism and stop it closing, so more frequent testing may be warranted.
The responsible person under the Regulatory Reform (Fire Safety) Order 2005, which requires fire safety provisions - including fire dampers - to be maintained in efficient working order. The testing itself must be done by a competent person.
The damper's condition - corrosion, obstruction, grease build-up, damage - and that the mechanism and any fusible link or actuator are sound, with the result recorded and any failed dampers identified for repair.
We clean ductwork including around fire dampers, clearing the grease build-up that can stop a damper closing - so it can do its job when a fire comes.
