Receptacles beneth Hood

[augie47]

I realized this is not directly NEC but I have been asked about a job where there is no building inspector/fire marsahll input.
A new restaurant has a hood protected by a dry chemical 'Ansul' system. The only electrical under the hood consist of a pizza oven with two motors operated off a twist lock outlet.
The motors themselves are not heat producing. Do the appropriate Code require the receptacles be de-energiized when the Ansul system activates ?
(The air systems are handled thru a pre-fab controller but there is disagreement concerning the under hood electrical)

 

[MasterTheNEC]

Now I am going off memory but I believe that all electrical under the hood has to de-energize on activation. I have my ICC Fire book at home and can look when I get off work but I believe that was the case.

Check this Section...

[F] 904.11.2 System interconnection.
The actuation of the fire suppression system shall automatically shut down the fuel or electrical power supply to the cooking equipment. The fuel and electrical supply reset shall be manual.

 

[retire09]

No. The only electric that is required to shut down is that which is the fuel for the cooking appliances under the hood.

 

[gadfly56]

No. The only electric that is required to shut down is that which is the fuel for the cooking appliances under the hood.

If the only codes in question were NFPA 17A and NFPA 96, you would be correct. However, if a jurisdiction uses the IBC or IMC, their requirements are more strict. So yes, the outlets would have to be turned off. It's ridiculous, but there you go.

I'm more concerned about a "new" restaurant having a hood protected by a dry chemical suppression system, if the OP is in fact correct on this. Dry chemical systems have been verboten for new installs since 1994. If the restaurateur was trying to save a buck by scavenging something from e-bay, he won't be a happy camper in the event of a fire. First, it likely won't put the fire out, and second, when the insurance company finds out, they won't pay a dime on the claim.

 

[augie47]

If the only codes in question were NFPA 17A and NFPA 96, you would be correct. However, if a jurisdiction uses the IBC or IMC, their requirements are more strict. So yes, the outlets would have to be turned off. It's ridiculous, but there you go.

I'm more concerned about a "new" restaurant having a hood protected by a dry chemical suppression system, if the OP is in fact correct on this. Dry chemical systems have been verboten for new installs since 1994. If the restaurateur was trying to save a buck by scavenging something from e-bay, he won't be a happy camper in the event of a fire. First, it likely won't put the fire out, and second, when the insurance company finds out, they won't pay a dime on the claim.

The OP (me) was opening mouth with foot close-by
When the question was posed to me I asked if the system was "wet or dry" and was told "dry". I have no first hand info the exact particulars.. I've seen the hood but there is no suppression system there yet.
What chemical is used these days ?

 

[david]

The OP (me) was opening mouth with foot close-by
When the question was posed to me I asked if the system was "wet or dry" and was told "dry". I have no first hand info the exact particulars.. I've seen the hood but there is no suppression system there yet.
What chemical is used these days ?

I wonder why they put the pizza oven under the hood in the first place, is equipment that is required to be protected in this way?

 

[augie47]

Low bid G/C, no drawings, used equipment, non-English speaking restaurant management on site "assisting", 'residential' electrician etc.
The refrigerator may end up under the hood

 

[retire09]

The IBC, IFC and IMC all refer to the fuel for the cooking appliances.
I would still say a 120 volt outlet for uses other than fuel to heat cooking appliances would not apply.

 

[LIM]

I wonder why they put the pizza oven under the hood in the first place, is equipment that is required to be protected in this way?

Pizza Ovens usually require a type 1 hood by the AHJ. All outlets serving the equipment would need to lose power through a shunt or other device upon activation of the suppression system. The owner's ANSUL system most likely is not dry. They at one time produced a white powdery substance, now it is more of a wet foam.

 

[Npstewart]

I realized this is not directly NEC but I have been asked about a job where there is no building inspector/fire marsahll input.
A new restaurant has a hood protected by a dry chemical 'Ansul' system. The only electrical under the hood consist of a pizza oven with two motors operated off a twist lock outlet.
The motors themselves are not heat producing. Do the appropriate Code require the receptacles be de-energiized when the Ansul system activates ?
(The air systems are handled thru a pre-fab controller but there is disagreement concerning the under hood electrical)

This would be in either NFPA 96 or NFPA 17.

NFPA 96 - 2011, 10.4.1 is attached. Going by the word of the code, I would say the conveyors dont have to be shut off because they dont produce heat but over the years I think this section has been interpreted as any electrical.

 

[mopowr steve]

Something tells me a number of years ago we did a pizza restaurant and the pizza oven sat under a simple hood that was merely only to exhaust heat and fumes and the exhaust blower was connected to a relay that would actuate "off" if duct smoke detectors in a tempered MAU that supplied air to an area nearby (So as to not create negative pressure in the restaurant and not draw in cold air).
No chemical fire suppression. After all how would it be aimed at anything? At the big stainless steel box pizzas are baked in?
The gas valve may have also been connected to relay but I Don't recall the receptacles that powered the pizza oven being shunt tripped or controlled by relay, after all if there was an alarm condition the gas would have been shut down.
Pizza ovens are pretty well enclosed I think, so fire spread should be minimal to non-existent.

 

[gadfly56]

Pizza Ovens usually require a type 1 hood by the AHJ. All outlets serving the equipment would need to lose power through a shunt or other device upon activation of the suppression system. The owner's ANSUL system most likely is not dry. They at one time produced a white powdery substance, now it is more of a wet foam.

NO!! Pizza ovens require Type II hoods and DO NOT need to be covered by a suppression system. Type I hoods are required only for appliances that produce "grease-laden vapors". Pizza ovens are not considered to be in this category, no matter how much pepperoni and extra cheese you like on your pie. If the only thing under this hood is a pizza oven then no suppression system is required, local laws excepted.

 

[MasterTheNEC]

FYI- My reference was to a Type I hood....The inspectors did not determine which it needed to be as that was done by the Mechanical Engineer and Mechanical and Gas Plan Reviewer. The inspectors just verified and I believe the ones I saw where not pizza ovens...they were Type I hoods and did shut down all power to the units...if they were plugged in then it shunted it down to the receptacles.

But that was many moons ago......so I don't dabble in those codes anymore...just the NEC and UL Standards

 

[gadfly56]

The OP (me) was opening mouth with foot close-by
When the question was posed to me I asked if the system was "wet or dry" and was told "dry". I have no first hand info the exact particulars.. I've seen the hood but there is no suppression system there yet.
What chemical is used these days ?

Either potassium acetate or potassium carbonate. In fact, Pyro-Chem's product line uses "PCL" as the prefix for each cylinder model, as in Potassium Carbonate Liquid. Both have fairly high pH's and will irritate your skin and REALLY irritate your eyes. Both compounds are slicker than soap when dissolved in water, and you have to move very slowly over a floor if the system's let loose in the kitchen. Clean up is basically just rinse it away.

 

[guitarman21632]

All power under the hood needs to be shut off regardless of what it is for. Typically it should also shut down the make-up air fan so as not to bring oxygen to the fire and shut down the exhaust fan too so it doesn't suck the dry chemical out. I have seen some jurisdictions have the exhaust stay on though to act as a smoke evacuation system

 

[electricalist]

I know very little on the subject but the ones I have worked on everything electrical under the hood was shunted except the exhaust air. Incoming air was shunted. Again it's from memory.
If there's a fire and it's the plug in question it could spread when the exhast came on.

 

[LIM]

NO!! Pizza ovens require Type II hoods and DO NOT need to be covered by a suppression system. Type I hoods are required only for appliances that produce "grease-laden vapors". Pizza ovens are not considered to be in this category, no matter how much pepperoni and extra cheese you like on your pie. If the only thing under this hood is a pizza oven then no suppression system is required, local laws excepted.

I agree with your explanation. Our locals do require a type 1 hood

Something tells me a number of years ago we did a pizza restaurant and the pizza oven sat under a simple hood that was merely only to exhaust heat and fumes and the exhaust blower was connected to a relay that would actuate "off" if duct smoke detectors in a tempered MAU that supplied air to an area nearby (So as to not create negative pressure in the restaurant and not draw in cold air).
No chemical fire suppression. After all how would it be aimed at anything? At the big stainless steel box pizzas are baked in?
The gas valve may have also been connected to relay but I Don't recall the receptacles that powered the pizza oven being shunt tripped or controlled by relay, after all if there was an alarm condition the gas would have been shut down.
Pizza ovens are pretty well enclosed I think, so fire spread should be minimal to non-existent.

They have to extend the heads down to spray into the conveyor area of the oven. I have seen may Domino's like this around here.

 

[fmtjfw]

All power under the hood needs to be shut off regardless of what it is for. Typically it should also shut down the make-up air fan so as not to bring oxygen to the fire and shut down the exhaust fan too so it doesn't suck the dry chemical out. I have seen some jurisdictions have the exhaust stay on though to act as a smoke evacuation system

In uor jurisdiction the make up air fan is forced off and the exhaust fan is forced on if the supression system trips (detects a fire). YMMV

 

[jap]

Most new designs show to shut down all the electrical within the boundary of the hood regardless of what it feeds.
As far as the exhaust and supply fan, the supply fan is shut down if the system is activated to keep from feeding the flames, but the Exhaust fan is left running to draw the smoke and fire retardant up through the exaust vent.

JAP>

 

[augie47]

All power under the hood needs to be shut off regardless of what it is for. Typically it should also shut down the make-up air fan so as not to bring oxygen to the fire and shut down the exhaust fan too so it doesn't suck the dry chemical out. I have seen some jurisdictions have the exhaust stay on though to act as a smoke evacuation system

Have a Code reference ? Note post #10, with reference, addresses electrical power to heat producing equipment,
The discrepancy it the heart of the problem