Fire suppression systems

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cnelectricllc

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Hello to everyone, I'm just starting to get more involved in these fire suppression systems and I want to double check to make sure I'm understanding them correctly. Any electric associated with the cooking area should be tripped under a fire situation. Once fire trips and sets off alarm it will shut down gas, hood lights, hood fan, and electric within a certain distance of grill, than any air being supplied in room gets cut off make up air ,ac and so on. Am I wrong with hood fan shutting down it sounds like this process would choke out the fire, any one that would like to give some input would be great.

Thanks for all who responds
 
cnelectricllc said:
Hello to everyone, I'm just starting to get more involved in these fire suppression systems and I want to double check to make sure I'm understanding them correctly. Any electric associated with the cooking area should be tripped under a fire situation. Once fire trips and sets off alarm it will shut down gas, hood lights, hood fan, and electric within a certain distance of grill, than any air being supplied in room gets cut off make up air ,ac and so on. Am I wrong with hood fan shutting down it sounds like this process would choke out the fire, any one that would like to give some input would be great.

Thanks for all who responds
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All kitchen suppression systems are listed for exhaust fan on OR off. That said, many, if not most jurisdictions want the fan ON. Why would you do that, you say? With the exhaust running, the air flow tends to pull the fire and smoke away from the front of the cook line. If that's the only exit path from the kitchen, you'll appreciate that in retrospect.
 
Also any grease burning in the exhaust ducting has it's heat forced out the exhaust instead of getting hotter inside the duct as it continues to burn, helps keep duct exterior from being heated enough to ignite materials outside the duct. Sort of turns it into a forced air heater instead of just a fire in a container.
 
I have wired many hood systems, both new and upgrade. When system trips:

The exhaust fan must turn on (in night mode) or stay on.

The make-up air must turn off or stay off (in night mode).

Any electrical appliance or outlet under the hood must lose power.

If gas w/solenoid valve w/reset box, exhaust must be on for gas to flow.

If gas w/mechanical valve, must have T-stat in hood activate exhaust.

Horn/strobe or connection to building fire alarm system must activate.
 
kwired said:
Also any grease burning in the exhaust ducting has it's heat forced out the exhaust instead of getting hotter inside the duct as it continues to burn, helps keep duct exterior from being heated enough to ignite materials outside the duct. Sort of turns it into a forced air heater instead of just a fire in a container.
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Equally as well, there are nozzles in the duct or at the bottom of it and the flow of air pulls the fire suppression agent up into the ductwork and fan.

LarryFine said:
If gas w/solenoid valve w/reset box, exhaust must be on for gas to flow.

If gas w/mechanical valve, must have T-stat in hood activate exhaust.
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Gas valve must turn off when system trips. Must be manually reset. Reason for having to manually reset gas is because most appliances use a standing pilot or may have been left on. So the resumption of gas must be supervised. Usually, but not always there is a T-stat in hood to turn exhaust and makeup fan on if they haven't been manually turned on already. Nothing to do with gas valve, you just don't want some pin head using the burners without turning on the fans.

Nickhxc4life said:
Are we talking strictly ANSUL systems for kitchen hoods here or fire supression in general for buildings? Two different animals.
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ANSUL systems.

-Hal
 
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hbiss said:
Gas valve must turn off when system trips. Must be manually reset. Reason for having to manually reset gas is because most appliances use a standing pilot or may have been left on. So the resumption of gas must be supervised. Usually, but not always there is a T-stat in hood to turn exhaust and makeup fan on if they haven't been manually turned on already. Nothing to do with gas valve, you just don't want some pin head using the burners without turning on the fans.
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Absolutely, I forgot to mention that part, as the reset is usually wired into the system that way already.
 
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