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#92191 - 03/05/05 12:38 PM shunt trips for kitchen hood  
triple  Offline
Joined: Apr 2002
Posts: 184
I'd like to find the NFPA article that requires these breakers or at least some automatic form of circuit de-energizer for electrical equipment under a grease hood.

Do the following devices fall under this rule?

- General-use, 120V receptacles
- Fully enclosed ("weather tight") lights supplied with the hood
- Exhaust fans
- Hvac supply to room

Where can I buy the particular NFPA article concerning this issue? I already did a search here on this subject but nobody has provided the article.

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#92192 - 03/05/05 01:42 PM Re: shunt trips for kitchen hood  
George Corron  Offline
Joined: May 2001
Posts: 717
Lorton, Va USA
Wow, you caught me at work on Saturday.
NFPA 96 7-4.1 Upon activation of any fire extinguishing system for a cooking operation, all sources of fuel and electric power that produce heat to all equipment requiring protection by that system shall automatically shut off.

7-4.2 Any gas appliance not requiring protection, but located under the same ventilating equipment, shall also automatically shut off upon activation of any extinguishing system.

7-4.3 Shutoff devices shall require a manual reset.

Close enough?

What's the outlet for? If it has a waffle iron plugged in (or has the potential) it is included.

the lights you quote do not produce fire causing heat - FM here would say no.

Exhaust fans - hmm, let's think, I've got a fire, so the best thing I can do is to suck it up into a greasy duct and provide fresh air as well, NO, it shuts down when everything else does.

HVAC supply to room, they do not make us do that locally, I can find no code reference to it.

Hope that helps.

#92193 - 03/05/05 02:35 PM Re: shunt trips for kitchen hood  
triple  Offline
Joined: Apr 2002
Posts: 184
Excellent response! Thanks allot! Now where can I purchase this article?

#92194 - 03/05/05 02:49 PM Re: shunt trips for kitchen hood  
mhulbert  Offline
Joined: Oct 2004
Posts: 132
Anaheim, CA USA
Some FM's want the exhaust fans to remain on. If there is a fire up in the ducting, some of the Ansul will get sucked up in there. Also, it gets the smoke out of the kitchen.

Make Up fans/HVAC get shut down for sure, no need to keep feeding the fire with fresh oxygen, or suck it into the rest of the restaurant.

#92195 - 03/06/05 10:01 AM Re: shunt trips for kitchen hood  
Roger  Offline
Joined: May 2002
Posts: 1,716
Triple, you can purchase the NFPA 96 at the link below.


[This message has been edited by Roger (edited 03-06-2005).]

#92196 - 03/07/05 11:09 PM Re: shunt trips for kitchen hood  
e57  Offline
Joined: May 2003
Posts: 2,876
The HVAC and Hood fans always seem to change at whim. Sometimes they want it all off including the hood. Sometimes just fire/smoke dampers on HVAC with hood on full. I have come to not take anything for granted, and ask up front.

As far as things on the line it seems best to do it all on shunts or relays. (Except lights)

Mark Heller
"Well - I oughta....." -Jackie Gleason

#92197 - 03/08/05 01:01 AM Re: shunt trips for kitchen hood  
nesparky  Offline
Joined: Jun 2001
Posts: 642
Like e57 said check with the AHJ before you install a hood electrical system.
Last resturant we did the FM required the exhaust fans to stay running, and all electric and gas to shut down including the lights. He also required the fresh or make up air unit to shut down. He also wanted the hoods ansul system to cause an alarm condition in the fire alarm panel
His explanation was that all sources of heat or power were to be off no fresh air in and the smoke to be exhausted. The alarm was to cause the building to be evacuated and the alarm company to call in the fire to the local 911 center.


#92198 - 03/08/05 07:22 PM Re: shunt trips for kitchen hood  
golf junkie  Offline
Joined: Apr 2001
Posts: 507
York, NE
I have done many of these over the years. They have always been set up like NEsparky describes. Intake air goes off, exhaust keeps runnng.


#92199 - 03/08/05 09:55 PM Re: shunt trips for kitchen hood  
electure  Offline

Joined: Dec 2000
Posts: 4,260
Fullerton, CA USA
I've been in the same boat as e57, and have had to do it both ways.

I prefer electrically held contactors to shunt trip C/Bs.
1.) The breaker supplying the power to the trips themselves might get turned off (even with a lockon) and go unnoticed [Linked Image]
2.) Breaker space is usually at a premium in kitchens, never seems to be enough. The shunt trip needs an extra pole space.
3.) Contactor = less $$, and easier to get.

#92200 - 03/10/05 02:50 PM Re: shunt trips for kitchen hood  
tdhorne  Offline
Joined: Mar 2001
Posts: 345
Maryland, USA
The kitchen exhaust system standard requires that the exhaust fan come on or stay on when the suppression system discharges unless the fire extinguishing system manufacturer requires shut down as part of the instructions included with the listing and labeling of the hood system. Use the hood system dry contact to re energize the exhaust fan motor contactor. If the exhaust fan is controlled by a manual motor control switch wire a load rated contactor in parallel with the manual switch and use the hood system dry contact to control the contactor.
Tom H

Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison

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