Kitchen hoods

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Sra328 said:
In my experience there will be a hood control panel which is provided separate from the ansul cabinet, i wouldn’t call the cabinet where the ansul bottles live a control panel per se.
In my area captiveair is the big name for kitchen hoods/CP’s
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The ones I've done usually do have the control box inside the same cabinet as the tanks.
 
As a side point, many of the gas valves are not electric, but mechanically connected to the fire suppression system to close when the system is activated, so don’t freak if you see no wires on it.
 
gadfly56 said:
I'm with Sra328 about consolidating the shunt feature in a panel with a main shunt. If you do, make sure the exhaust fan doesn't wind up on this panel! Power the shunt coil from one of the devices being shut down. This means putting two hots at one of the breakers; make sure that it's listed for putting two conductors under one screw.
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Or give it its own circuit, but with a control box, there are usually shunt-trip terminals.
 
brantmacga said:
If there’s a remote hood there should also be a whip for the thermocouple that needs to connect to the control panel.
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If you mean a thermal switch in the hood, that's normally required with mechanical gas valves.

Your gear seems to be already setup with the required shunts but as an fyi you don’t have to shunt all electric power, only that to heat-producing equipment.
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Here, every source of electricity must shut off; every receptacle, used or not; even the lights.
 
LarryFine said:
If you mean a thermal switch in the hood, that's normally required with mechanical gas valves.


Here, every source of electricity must shut off; every receptacle, used or not; even the lights.
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If you go back and forth between NFPA 17A and NFPA 96 there is a certain amount of circular reasoning going on. I agree it should only be for heat-producing equipment, but AHJ's in my area have a different opinion.
 
hillbilly1 said:
As a side point, many of the gas valves are not electric, but mechanically connected to the fire suppression system to close when the system is activated, so don’t freak if you see no wires on it.
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Right. There are mechanically-held valves and solenoid valves.

With mechanical valves, preferred when there are standing pilot lights, there is a thermal switch in the hood that activates the fan(s) if someone starts cooking without turning on the exhaust.

With solenoid valves, the gas won't flow unless the exhaust is turned on.
 
gadfly56 said:
If you go back and forth between NFPA 17A and NFPA 96 there is a certain amount of circular reasoning going on. I agree it should only be for heat-producing equipment, but AHJ's in my area have a different opinion.
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Many commercial cooktops and appliance bases have refrigeration compartments.

I think electrical shock is also a concern.
 
LarryFine said:
If you mean a thermal switch in the hood, that's normally required with mechanical gas valves.


Here, every source of electricity must shut off; every receptacle, used or not; even the lights.
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thermocouple in the duct is required by NFPA 96 8.2.3.3 "The exhaust fan shall be provided with a means so that the fan is activated when any heat-producing cooking appliance under the hood is turned on." That's the easiest way to accomplish this; it senses the temp rise and turns the fan on, but also makes sure it keeps running when the equipment is off until all the heat is gone. You can interlock the fan through the cooking equipment but you've got to order specific equipment for that. It usually comes as an additional 5-wire twist-lock plug. There's also the option of using a contactor on the power for hood equipment so it's only on if the fan is on, but I really haven't seen that utilized.

NFPA 96 10.4.1 -- "Upon actuation of any fire-extinguishing system for a cooking operation, all sources of fuel and electric power that produce heat to all equipment protected by the system shall automatically shut off. "

I know there are inspectors that want everything off as I've had those arguments as well.
 
Here's the relevant info from NFPA 96.... I keep this saved as a note on my phone.

8.2.3.1 A hood exhaust fan (s) shall continue to operate after the extinguishing system has been activated unless the fan shutdown is required by a listed component of the ventilation system or by the design of the extinguishing system.

8.2.3.2* The hood exhaust fan shall start upon actuation of the extinguishing system if the exhaust fan and all cooking equipment served by the fan have been shut down, unless the fan shutdown is required by a listed component of the ventilation system or by the listing of the extinguishing system.

8.2.3.3 The exhaust fan shall be provided with a means so that the fan is activated when any heat-producing cooking appliance under the hood is turned on.

8.3.2 When the fire-extinguishing system activates, makeup air supplied internally to a hood shall be shut off.

10.4.1 Upon actuation of any fire-extinguishing system for a cooking operation, all sources of fuel and electric power that produce heat to all equipment protected by the system shall automatically shut off.

10.4.2 Steam supplied from an external source shall not be required to automatically shut off.

10.4.3 Gas appliances not requiring protection but located under the same ventilation equipment where protected appliances are located shall also be automatically shut off upon actuation of the extinguishing system.

10.4.4 Shutoff devices shall required manual resetting prior to fuel or power being restored.

10.4.4.1 Where an electrical gas valve is used for shutting off gas appliances, a manually reset relay shall be used to restore electrical power to the gas valve.

10.4.5 Solid fuel cooking operations shall not be required to be shut down.
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brantmacga said:
thermocouple in the duct is required by NFPA 96 8.2.3.3 "The exhaust fan shall be provided with a means so that the fan is activated when any heat-producing cooking appliance under the hood is turned on." That's the easiest way to accomplish this; it senses the temp rise and turns the fan on, but also makes sure it keeps running when the equipment is off until all the heat is gone.
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I was always given a thermal switch set at 100 deg. and a timer module I adjusted to 10 minutes.

This automatic operation was sometimes referred to as "night mode".
 
LarryFine said:
This is a good idea if the breakers are not already in place.
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agreed, he said it was new construction. not sure how far along his project is in terms of submittals/procurement. This was always one of the first things one of my old PM's looked at if there was more than a handful of 1P/20A ckts. It's now just second nature for me to do the same for my foremen when we are awarded a job with a commerical kitchen involved.

here, every inspector i have dealt with has required all circuits to open on ansul activation. I was always told it was due to the ansul product being a good conductor of electricity 🤷‍♂️

Hopefully OP returns with good news.
 
Sra328 said:
agreed, he said it was new construction. not sure how far along his project is in terms of submittals/procurement. This was always one of the first things one of my old PM's looked at if there was more than a handful of 1P/20A ckts. It's now just second nature for me to do the same for my foremen when we are awarded a job with a commerical kitchen involved.

here, every inspector i have dealt with has required all circuits to open on ansul activation. I was always told it was due to the ansul product being a good conductor of electricity 🤷‍♂️

Hopefully OP returns with good news.
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You are far more likely to wind up with a concussion from slipping on the suppression agent that winds up on the floor than suffer an electric shock. That stuff is slippery as heck, and you'll be doing the old man shuffle anywhere it lands.
 
How can you upload images here? Trying to upload a drawing I found online I wired it exactly the same and it works but suppression system guy said I used both of the micro switches now trying to figure out how to wire system with only one micro switch and contactors.
 
FZ91 said:
How can you upload images here? Trying to upload a drawing I found online I wired it exactly the same and it works but suppression system guy said I used both of the micro switches now trying to figure out how to wire system with only one micro switch and contactors.
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Click on the icon above the reply box that looks like the state of VA, or mountains and the sun.
Click on Drop Image if it's on your computer, or click on the chain if it's a URL on the web.
 
You should need to wire only one micro-switch to the control box in most instances.

The control box should have a trio of terminals for one. What did you connect each of yours to?

Normally, you just wire everything to terminals in the control box, especially if it as fan contactors.
 
brantmacga said:
If there’s a remote hood there should also be a whip for the thermocouple that needs to connect to the control panel.



Your gear seems to be already setup with the required shunts but as an fyi you don’t have to shunt all electric power, only that to heat-producing equipment.


Sent from my iPhone using Tapatalk
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I tried telling that to various people on my job and everyone disagreed and rejected that. fire department and their independent inspecting company.

I probably learned about what you mentioned by you on here. I did learn it on here
 
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