Commercial vent hood

[Bohica bob]

I have somehow avoided wiring a restuarant to this point in my career, and know im on the vent hood . My question is does the range and everything on the floor under the hood have to shut down with the shunt trip, and how is that done normally ?

 

[kwired]

They generally only place appliances that require said shut down under the hood. If it is an appliance that won't require shut down hood is too expensive utilize space under it for appliances that don't need shut down. So typically everything under it will normally be required to be shut down if the fire suppression system is activated.

There is basically two ways to do this. One is to have normally open held closed limit switch in the fire suppression system to control a contactor(s) for the equiment under the hood. If the fire suppression system is actuated, it opens the circuit and contactors drop out opening the circuit to the loads they control. The other option is to use the other function of the limit switch (normally closed held) - when the fire suppression system is actuated the switch closes and sends power to shunt trip breaker(s) trip coil supplying power to appliances under the hood - this trips the breakers which of course removes power from the appliances.

 

[hbiss]

In most cases electrically heated appliances don't need to be under a hood, only gas or propane fired. (Unless your code is different.) So there shouldn't be receptacles there, only the under hood lighting. Instead you are going to have a gas valve that will shut off the gas supply to everything when the fire suppression system activates.

-Hal

 

[kwired]

In most cases electrically heated appliances don't need to be under a hood, only gas or propane fired. (Unless your code is different.) So there shouldn't be receptacles there, only the under hood lighting. Instead you are going to have a gas valve that will shut off the gas supply to everything when the fire suppression system activates.

-Hal

I don't know codes, but most every conventional "fryer" I have ever seen triggers the need for a hood with fire suppression system regardless if it is gas or electric.

Have churches and other local organizations that have fish fry's during lent season, fire marshal in more recent years won't let them use fryers inside unless they install vent hoods. Many of them now have outdoor frying stations, or someone that has mobile equipment on a trailer that they do the frying on, usually propane fueled for mobility reasons.

Seen a few small convenience stores that sell burgers and fries and similar items that use an "AutoFry" appliance that is designed to not need an additional hood.

 

[hbiss]

I don't know codes, but most every conventional "fryer" I have ever seen triggers the need for a hood with fire suppression system regardless if it is gas or electric.

I agree that they all should (a grease fire is a grease fire) but most electric fryers are "table top". The codes for the installation vary from location to location. NG or propane also generates CO that you don't have with electric.

Probably @brantmacga would know more about this.

-Hal

 

[LarryFine]

General rules:

Exhaust fan must turn on or stay on
Make-up fan must turn off or stay off
Every appliance and receptacle must turn off
In most places, hood lights must turn off

Gas must shut down, electric or mechanical
Electric gas can turn on only if exhaust is on
Mechanical gas requires duct t-stat and timer
Most with standing pilots opt for mechanical