connecting smoke damper actuators 2

[wtlive]

By code does the power feeding smoke damper actuators need to be on emergency power?

 

[davidbeach]

Only if you are doing active smoke control using fans on emergency power. Smoke dampers are held open and close on loss of power.

 

[waross]

100% with david beach with the 99.99% of the time with following exception.
I saw some smoke dampers years ago that were gravity operated and held open with fusible links. There was an integral electric heater to melt the link. They were of course "One Time Only Devices" and had to be replaced after every use. We lost a couple during test and commissioning. They would operate on either a high ambient temperature or from a signal from the fire alarm panel. They were powered from the fire alarm system.

 

[davidbeach]

What you are describing waross is a fire damper. Used to be that HVAC systems used fire dampers where crossing zone boundaries, but for quite a while now the requirement is for smoke dampers.

 

[waross]

Thanks for the info davidbeach
I've been away from North America for quite awhile now and away from comercial for even longer. And yes, I do remember now that it was a fire damper. I stand corrected.