Wherever a ventilation duct crosses a fire separation, that separation would have a hole in it without measures. The fire damper solves that: in a fire, the damper closes the duct so fire and smoke cannot spread to another compartment via the ventilation system. A damper that does not close - or is not installed correctly - undermines the entire compartmentalization, no matter how well the rest of the separation is executed.
How does a fire damper work?
Most fire dampers work with a fusible link or a thermal sensor that closes the damper blade at a set temperature (usually around 72 °C), often assisted by a spring. In buildings with a fire alarm system, dampers are increasingly controlled electrically, so that they close at an early fire signal, before the temperature on site has risen.
Three standards play a role, each with its own function. A fire damper is tested in accordance with NEN-EN 1366-2 and classified in accordance with NEN-EN 13501-3, for example as EI 60 S, where the S stands for limited smoke leakage. The product standard NEN-EN 15650 describes the requirements for the fire dampers themselves, including the CE marking.
The surrounding seal is just as important as the damper
A common assumption is that a certified damper automatically results in a fire-resistant penetration. That is only true if the damper is also installed with the prescribed installation between the damper casing and the wall or floor. Depending on the damper and the construction, this is for example mortar, a mineral wool package or an approved dry installation kit, always in accordance with the installation instructions and within the damper's field of application. A damper that works technically but hangs loose in an oversized opening still lets smoke and flames past the casing in a fire.
How often should a fire damper be tested?
A fire damper needs a periodic function test, in which the closing mechanism is actually activated and checked. How often is determined first and foremost by the manufacturer, and differs per type. An example: for the FK2-EU type, TROX specifies a function test at least every six months; after two consecutive successful tests six months apart, the next test may follow a year later. That instruction applies to that type and must not be applied to other dampers without assessment.
The use of the building, the installation and any agreements with the insurer or manager also play a role. With dirty or greasy air, or in critical environments such as care and data centres, a shorter cycle may be needed. For building installations covered by Article 2.6 Bbl, manufacturers' instructions are an important starting point according to the Informatiepunt Leefomgeving.
| Check point during a function test | Why it matters |
|---|---|
| Does the damper close fully and on time | A partially closed damper offers no fire resistance. |
| Does the damper reopen after reset (where applicable) | Prevents unnecessary ventilation downtime after a test or fault. |
| Is the surrounding seal still intact | It sometimes gets damaged after renovations or nearby pipework. |
| Is the damper accessible for inspection | Dampers that have been built over or made inaccessible cannot be tested or maintained. |
Common mistakes
- Missing or incorrect installation. The damper itself is in order, but the connection to the wall or floor has not been made in accordance with the installation instructions.
- Skipping function tests. A jammed or corroded mechanism often only becomes apparent during a test - not during normal use.
- Making it inaccessible after renovation. A new suspended ceiling or fixed furniture blocking the inspection hatch makes maintenance impossible without demolition work.
Not sure whether all the fire dampers in your building still demonstrably work? We test, repair, and register them in a digital logbook, as a one-off visit or within a maintenance contract.
Frequently asked questions
According to the manufacturer's instructions, which differ per type. For the FK2-EU, for example, TROX specifies a function test at least every six months; after two consecutive successful tests the interval may be extended to a year. Use, air quality and agreements with the insurer or manager may call for a shorter cycle.
The installation counts just as much. Without the prescribed installation between damper and wall or floor, in accordance with the installation instructions, even a certified damper does not provide full fire resistance.
The fire separation is no longer intact at that point: fire and smoke can spread to the next compartment via the ventilation duct. A malfunctioning damper must be repaired or replaced as a priority.
Want to know more about fire dampers?
Installing, testing and maintaining fire dampers: automatic shut-off of ventilation ducts at every compartment boundary.
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