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Extraction cleaning - fire dampers
A fire damper is a small device with one critical job: to slam shut and block fire from travelling through your ductwork. Drop testing is how you prove it still will - and it has a schedule you are expected to keep.
The short answer
A fire damper sits in ductwork where it passes through a fire barrier and is designed to close automatically in a fire, stopping flames and smoke spreading through the duct. Drop testing releases the damper to confirm it still closes fully and reseals. BS 9999 calls for testing on installation and at least annually thereafter - and more often, typically every six months, in dust-laden or high-risk settings like commercial kitchen extract.
What a fire damper does
Buildings are divided into fire compartments - walls and floors designed to hold a fire in one area for long enough to protect people and property. The problem is that ductwork passes straight through those barriers, giving fire and smoke a ready-made route from one compartment to the next. A fire damper is what closes that route.
Set into the duct where it crosses a fire barrier, the damper is held open in normal use and closes automatically when a fire is detected - usually when a fusible link melts at a set temperature or an actuator triggers. Once shut, it restores the integrity of the fire barrier the duct had breached. It is a small component doing a critical safety job, out of sight.
What drop testing is
Because a fire damper spends its whole life held open and only ever needs to work once, in a fire, there is no everyday sign of whether it still functions. Drop testing is how that is checked. A competent person releases the damper to confirm it drops fully closed under its own mechanism, reseals properly, and can be reset - and inspects its condition, linkages and any springs or actuators.
The test matters because dampers fail silently. Grease and dust can clog the mechanism, linkages seize, springs weaken, and a damper that looks fine can be one that will not close when it is needed. Drop testing is the only way to know the barrier will actually restore itself in a fire rather than staying jammed open.
How often
The recognised standard, BS 9999, sets the frequency. Fire dampers should be tested by a competent person on completion of installation and at least annually thereafter. Newly fitted dampers are tested within a year of installation as a commissioning check, and testing is also needed after any alteration to the building, the ductwork or the fire strategy that could affect them.
In dust-laden or high-risk environments the interval shortens. Commercial kitchen extract systems are a prime example: the grease and debris that build up in kitchen ductwork are exactly what clogs a damper mechanism, so testing every six months is typically expected rather than annually. The dirtier and higher-risk the system, the more often the damper needs proving.
Where it overlaps cleaning
Fire damper testing and duct cleaning are closely linked, especially in kitchens. The grease build-up that a TR19 Grease clean removes is the same build-up that seizes a fire damper, so a system kept clean is a system where the dampers can actually close. A neglected, greasy duct is doubly dangerous - it is fuel for a fire and it is jamming shut the very device meant to contain one.
Access is shared too. Reaching a damper to test it needs access to the ductwork, the same access that cleaning requires, so the two jobs often make sense together. Keeping the ductwork clean and the dampers tested is a combined defence: less fuel for a fire, and working barriers to stop it spreading if one starts.
Why it matters
A building's fire strategy assumes the compartments hold - and a fire damper that fails to close breaks that assumption at the worst moment, letting fire and smoke travel the ductwork through barriers that were supposed to stop them. The consequences of a single stuck damper can be far out of proportion to the small device it is.
That is why the testing is not a paperwork exercise. Regular drop testing, at the right interval for the system, is what keeps the fire compartmentation actually working where ductwork crosses it. For a kitchen operator it sits alongside grease cleaning as part of managing the same underlying fire risk - and keeping the evidence that it has been done is part of demonstrating the duty is met.
Questions
Releasing a fire damper to confirm it still drops fully closed under its own mechanism, reseals and can be reset - plus inspecting its condition, linkages and springs. It proves the damper will actually close in a fire.
BS 9999 calls for testing on installation and at least annually thereafter, and typically every six months in dust-laden or high-risk settings such as commercial kitchen extract systems.
Because they spend their life held open and only need to work in a fire, with no everyday sign of failure. Grease and dust can clog the mechanism, so a damper can look fine but not close when needed.
Because grease and debris in kitchen extract ductwork are exactly what clogs a damper mechanism. The higher build-up and fire risk mean six-monthly testing is typically expected rather than annual.
Closely. The grease a TR19 Grease clean removes is the same build-up that seizes fire dampers, so a clean system is one where the dampers can still close. The access needed to test them overlaps with cleaning access.
It breaks the building's fire compartmentation, letting fire and smoke travel the ductwork through barriers meant to stop them. A single stuck damper can have consequences far out of proportion to its size.
We clean the extract system that clogs fire dampers and can check them where the ductwork is opened.
