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Colt Defender is a motorized fire damper suitable for use in all types of HVAC ductwork. It has been designed to prevent the passage of fire from one area to another.

Defender is operated by the fire detection system, with the additional back-up of a thermal link which closes the damper at a pre-determined temperature. In the event of a fire, the local Colt control panel closes the Defender in the specific duct. When all clear the damper will motor open.

24 volt DC motors are recommended, so that a simple battery back up system can incorporated to ensure the damper operates in the event of a mains failure.

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Standard product features


1.5 mm welded galvanized mild steel flange case incorporating 2 mm stainless steel interlocking blades and frame side seals, providing a four-hour fire rated assembly to BS 476-20 (1987).


Airtight to Class C according to DW 144.


200 x 200 mm up to 1000 x 1000 mm. Intermediate sizes and multiple assemblies available.


  • Precision blade linkage mechanism.
  • High free area.
  • Tested and approved to BS 476-20, providing a four hour fire rating and a 50,000 lifecycle test with damper fully operational at the test conclusion.


- Motor:

The damper is actuated by a drive in, drive out 24v DC or 230 v AC motor fitted to either the front, rear or the side.

- Closing:

A thermal link closes the damper at 720°C. Alternatively the damper will close when a signal is received from a fire detection system or when electrical supply fails.

NBS Specification

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This product is associated with the following NBS Create clause:
90-45-25/420 Fire and smoke dampers

NBS Specification

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This product is associated with the following NBS clauses:

Product specification

An important note about specifying



Colt International Ltd


+44 (0)23 9245 1111

Product reference

Defender motorized fire damper

Damper motor

 - Type:
[24 v DC]
[230 v AC]
 - Position:


[Electrical supply failure]
[Signal from fire detection system]
[Thermal link]

Manufacturer details

Colt House,
Ridgeway Office Park,
Bedford Road,
Hampshire, GU32 3FQ
Tel +44 (0)23 9245 1111
Fax +44 (0)23 9245 4220
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