Restaurant Fire Suppression controls

[powerplay]

Hello all,

I am installing an Potter Releasing Panel for Water and Agent Extinguishing System in an Restaurant, which shuts down the Make-Up Air system and leaves the exhaust fans running during a fire. The place has a) 2 exhaust fans
b) 2 make-up air units
c) 1 kitchen exhaust
d) 2 HVAC units (used to be 2 addresses)

If I control the Low voltage controls, the make up air and HVAC that have Heat Exchangers may run over a minute to allow the heat exchanger to cool down automatically, but during a fire the fresh oxygen needs to stop and the exhaust continue to remove smoke and steam. An option I am considering is to intercept the fans within the units on the rooftop itself to immediately cut off the fresh air, instead of waiting for the unit to cool down to shut off in case of fire...would this cause an issue if the exchanger isn't allowed to cool down before the fresh air is stopped during extinguishing statem activation?

Thanks again ! ...Powerplay

 

[benaround]

pp,

I don't think any issues would arise, but, the local inspector of the system is going to be

the only real answer.

 

[76teach]

I too have contemplated this, could there be damage to the hvac unit when anual testing is done without the actual emergency. I have as many schematics have shown broke control power in hvac units at the transformer output, thius dumping everyting. I know there are consequences when droping a boiler hot, it gains heat internally.

Some things I've been asked to do just make it hard to sleep at night

 

[powerplay]

One more thing that was pointed out by a friend is that if I cut off all the make-up air immediately, and continue exhaust...would there be a danger of a flashback when the door is opened and air entering the building? ..I know..it's an mechanical engineer question, but I figure we have some answers here?

 

[61333]

Sounds like you need to ask your Fire inspector, Electrical inspector and the mechanical engineer how to do this. Just to be on the safe side or hope that the company you work for has lots of insurance.

 

[One-eyed Jack]

You should not have a problem dropping the makeup air even if the source is heated as long as the heat drops at the same time. The same thing would happen if you had a power outage,even a momentary one. The yearly test does not necessarily have to have heat to test unless the Fire Marshal insists.

 

[powerplay]

Thanks for the replies.

The safety features are in place, such as the air verification switch which will disable the heater when the air doesn't flow. i was more curious if it damages anything within the make-up unit when it doesn't have moving air to cool it like a car radiator ...I suppose the fire below would be hotter...

 

[One-eyed Jack]

Thanks for the replies.

The safety features are in place, such as the air verification switch which will disable the heater when the air doesn't flow. i was more curious if it damages anything within the make-up unit when it doesn't have moving air to cool it like a car radiator ...I suppose the fire below would be hotter...

Don't trust this to drop gas valve . I have seen an install that had two air handlers in series with dampers etc on the discharge and the air flow switch was set for positive pressure to prove air flow. On activation the dampers would close, the heater fan would shut down but the outside air fan did not and kept pressure on system with no air flow. Heat continued until it shut down on high temp. This was solved by breaking the common side of all of the control transformers. Shut down of everthing was instant.