4
Parts and function
Tunnel fire dampers are used as safety related compo-
nents in ventilation systems. The fire damper is used as
a shut-off device to prevent fire and smoke from
spreading through ducting. During normal operation the
damper blade is open to enable air passage through the
ventilation system.
If the temperature increases in the event of a fire, the
damper blade closes. Closure is triggered at 72 °C. If
the damper blade closes due to a temperature increase
(i.e. in the event of a fire), it must not be reopened.
To ensure proper functioning of the fire damper, a test
can be carried out.
4.1 FKT-EU with spring return actuator
Fig. 3: FKT-EU with spring return actuator
①
Damper blade (calcium silicate)
②
Travel stop, damper OPEN
③
Casing (calcium silicate)
④
Installation subframe
⑤
Fixing screws for sealing strips (during transport)
⑥
Thermoelectric release mechanism BAT
⑦
Spring return actuator
⑧
Intumescent seal
⑨
Sealing strips
⑩
Rating plate
⑪
Travel stop, damper CLOSED
Functional description
The spring return actuator enables the motorised
opening and closing of the damper blade; it can be acti-
vated by the central BMS. As long as power is supplied
to the actuator, the damper blade remains open. In the
event of a fire, the internal thermoelectric release mech-
anism closes the damper blade when at least one of the
following is true:
Temperature in the fire damper > 72 °C
Ambient temperature outside the release mecha-
nism > 72 °C
The power supply is interrupted (power off to close)
As standard, the spring return actuator is equipped with
limit switches that can be used to indicate the damper
blade position.
Parts and function
FKT-EU with spring return actuator
Tunnel fire damper Type FKT-EU
11
