Fire Dampers insulation

[afa13]

Hey everyone,
I need your help on the following.
Do fire dampers (motorized) need insulation when they are installed in the supply or return line to prevent heat loss and condensation?
In the fresh air ductwork, you don't but I'm afraid that on the supply and return you might need to insulate the damper so as to prevent unwanted condensation. Am I right?
Thanks!

 

[chicopee]

As long as it does not overheat the motor or interfere with the linkage operation, I would be inclined to say go ahead. I know that we had to insulate the vent line of one of our hot air furnaces as the condensation would freeze and block the vent line. So I understand your predicament.

 

[afa13]

Chicopee,
The sides of the damper are insulated.
The motor is not so that heat can be dissipated to the surrounding air instead of it being trapped between the motor and the duct which might lead to condensation.
I did not want for the damper to be completely exposed to surrounding air, which might also lead to condensation.
I will apply the same thing for blast dampers and other motorized dampers on the supply/return line.
Linkage/blades locking mechanism are not affected because I kept that area insulation free. Do you agree?
Thanks for your answer!

 

[dbill74]

What does the fire damper manufacturer recommend?

 

[afa13]

The manufacturer says that it is o.k as long as the insulation doesn't interfere with the motor's operation much like what Chicopee said.

 

[Ziggypump]

It's a fire damper. How much heat is it going to generate? It should only operate to close the damper in the event of a fire, which the insulation will probably be gone. If the damper runs long enough to generate enough heat to prevent it from working, there's something wrong with the controller.

 

[rogzog]

IF it has a motor it is a Fire/Smoke damper. The motor is to close the damper when a smoke detector in the system detects smoke and the damper has a fusible link on the inside that will break when the internal air temperature gets too high allowing springs to close the damper independent of the motor. Just do not interfere with the linkage.

 

[rogzog]

Also check with your State or whatever Mechanical Inspector. It would be his call.

 

[Ziggypump]

rogzog, just had to deal with this on a project of mine. Not all fire/smoke dampers use a fusible link. There are some out there with an internal temperature sensor or something that will activate the motor. We were expecting a fusible link for the fire damper portion, but it's not there. So be careful in reviewing the combo dampers in the future.

 

[rogzog]

Ziggypump, yes sir you are absolutely right. I had only seen them shortly before I retired. They fail closed on power loss.