Commercial Kitchens hood and shunt trip breakers

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george nicholson

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I have been doing commercial kitchens since 1969. Here is what I have always done regarding disconnecting when a fire system is activated for the hood:

1) make-up air fan on hoods are disconnecetd when ANSUL fire system is activated --- exhaust fan still runs as do light.

2) the plumber has a mechanical valve in gas line to disconnect all gas appliances with ANSUL activation

3) if there are "HEAT PRODUCING" electical items under the hood I disconnect those with a shunt trip breaker activated via the ANSUL system. Like an electric fryer, electric grill, etc.

4) I do NOT disconnect general purpose receptacles that supply refrigeration power, timer power, or other non-heat generating electrical items that are under the hood.

Recently I have had 2 separate ANSIL fire protection companies tell me that under "NFPA96", NEC 2008, and "NFPA56 ?" that any outlet under the hood must be on shunt trip breakers even if its for a refrigeration. They will not tag their systems until we put all receptacles under the hood on shunt trip breakers even the ones not in use. I do NOT think this is required under any code.

I do have all GFCI's under the hood so that there is no liquid issue when the hood fire system is activated or when walls are being washed.

Can I please get some response as I do not want to install shunt trips where I do not feel they are required.
 
You can look in the NFPA codes online for free.

www.nfpa.org

Look at 10.4 of NFPA 96. I am inclined to agree with you, but it could be clearer.
 
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that way I just did my last one....

exhaust stays on, makeup air off, lights under hood off, any and all recepts under hood off, mechanical gas valve shut off with cable pull, electrical conrolled from micro switch on extinquisher canister
 
That's really the way I've seen it done also (all the power under the hood shut off).

But looking at NFPA 96, it says something like "all electrical for heat producing equipment" should be shut off.

Of course, there could be some other code that says all power must be shut off.

Steve
 
receptacles under commercial venthood

receptacles under commercial venthood

Why would a refrigerated base for a gas griddle be required to be disconnected? The receptacle is not producing heat? I am missing something.

What about a timer for a steamer that is gas fired? the gas is already disconnecetd by gas valve so all that is on by electrical power is a clock display?

*******************************************************
NFPA 96 2004 Edition, Section 10.4 Fuel Shut Off reads in:
Section 10.4.1 ? 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.
Section 10.4.3 ? Any gas appliance, not requiring protection, but located under the same ventilation equipment shall also automatically shut off upon activation of any fire extinguishing systems.
Section 10.4.4 ? Shut off devices shall require manual reset.
 
That's covered under NFPA 17 for dry chemical and NFPA 17A for wet chemical, but they both read the same:

2-4.3 Shutoff Devices.
2-4.3.1 Upon activation of any cooking equipment fire extinguishing
system, all sources of fuel and power to all equipment
protected by the system shall be shut down.
Gas appliances not requiring protection but located under
the same ventilation equipment shall also be shut off.

If you have a fridge under that hood, you can shut it down if you want to, but you're not required to.
 
And what's really fun with shunt-trip breakers is when the EE doesn't know each breaker takes up an extra space in the panel.

shunttripbreaker.jpg

Makes for laying out circuits according to the prints reeeeeeal fun.
 
480sparky said:
And what's really fun with shunt-trip breakers is when the EE doesn't know each breaker takes up an extra space in the panel.
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I've tended to favor a little sub for the underhood stuff, and just shunt trip the feeder breaker for that sub. Way cheaper that way. If it's just a couple circuits, I still favor a contactor. Maybe that is an engineering change, but I just mark it on the as builts and let someone else stress over it.
 
mdshunk said:
That's covered under NFPA 17 for dry chemical and NFPA 17A for wet chemical, but they both read the same:

2-4.3 Shutoff Devices.
2-4.3.1 Upon activation of any cooking equipment fire extinguishing
system, all sources of fuel and power to all equipment
protected by the system shall be shut down.
Gas appliances not requiring protection but located under
the same ventilation equipment shall also be shut off.

If you have a fridge under that hood, you can shut it down if you want to, but you're not required to.
Click to expand...


our local Firemarshall requires all power under the hood along with the lights to be shunt protected (or contactors) for saftey of the firefighters in event of responding to a fire under the hood...
 
ultramegabob said:
our local Firemarshall requires all power under the hood along with the lights to be shunt protected for saftey of the firefighters in event of responding to a fire under the hood...
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Every time I hear statements like that, I sorta get knotted up inside. Don't suppose you ever asked them what legally enforcable document they're basing that request on?
 
I suppose if I really wanted to make a stink about it, I could win a battle, but I dont really need the war.... and there is some logic to thier thinking, and as long as they require it across the board for everyone, and not just pick and choose when to enforce it, I dont really have a problem with it.....
 
ultramegabob said:
I suppose if I really wanted to make a stink about it, I could win a battle, but I dont really need the war.
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That's not at all what I'm talking about. I'm talking more about an educational inquiry. Maybe there is some basis for their request, and it would be nice to know.
 
Bob....as a fire fighter/fire inspector I understand the premis but we secure utilities when we're going in on a fire (for a kitchen fire it depends on what the first in finds). While I understand the premis, I do not concur with your FI's request unless there is a local ammendment to 96.
 
Marc, not to "knot you up" more, but our local Fire Mashall requires ALL electric to be disconnected on WET systems and only "heat producing" on dry systems. I've not pressed the point as the distinction seemed reasonable, in fact, so much so, that until you told me differently, I thought NFPA17 vs 17A were wqorded that way.

I have notice on a lot of the "factory wired" systems, the exhaust fan is wired to start wheh the system trips. Do you have any input on that ??
 
augie47 said:
Marc, not to "knot you up" more, but our local Fire Mashall requires ALL electric to be disconnected on WET systems and only "heat producing" on dry systems. I've not pressed the point as the distinction seemed reasonable, in fact, so much so, that until you told me differently, I thought NFPA17 vs 17A were wqorded that way.

I have notice on a lot of the "factory wired" systems, the exhaust fan is wired to start wheh the system trips. Do you have any input on that ??
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makeup air off so your not feeding fresh air to fire, exhaust on to remove smoke....
 
augie47 said:
I have notice on a lot of the "factory wired" systems, the exhaust fan is wired to start wheh the system trips. Do you have any input on that ??
Click to expand...
NFPA 96, 8.2.3.2 says that the exhaust is not required to start from a stopped condition on fire system activation if all the cooking appliances served by the hood have been previously shut down. Since there's not really any reasonable way for the relays to know if the stove or the fryer is on or not, they just start the fan. Not required, but not prohibited by any means. Just an extra step that sometimes might not be necessary and doesn't hurt a thing.
 
mdshunk said:
That's not at all what I'm talking about. I'm talking more about an educational inquiry. Maybe there is some basis for their request, and it would be nice to know.
Click to expand...


ultramegabob said:
for saftey of the firefighters in event of responding to a fire under the hood...
Click to expand...


I can appreciate that, but as kkwong stated if there is enough fire that we can't take care of it with a dry chem extinguisher, then we are going to shut of electrical and gas service to the entire building anyway so water and recepts will not be an issue.
 
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