The exhaust fans are supposed to continue running to pull the smoke out. I beg to differ with you, electure, about the electrically held contactors. IMHO Shunt trip breakers should be on all the electrical equipment under the hood. Any gas equipment should have valves that shut off as well. I don't like the idea of cooking equipment being dependant on an electrically held contactors. I submit this for your consideration, sir, with the utmost respect.
I am very interested because we are currently doing a commercial kitchen. It was engineered so that only the supply air is cut off. Electric range, lights, etc. all stay on.
I believe all electrically powered cooking loads / recepticles / lights have to be de-energized when the ansul dumps. Nothing can be live under the hood when it goes.
All of this is subject to the inspectors interpetation.
You should take a look at nfpa 96 for a clearer understanding.
The last couple of commercial kitchens I have done required a fire alarm tie in. They also had a "ventilation control panel" which allowed the chef to manually turn on and off hoods but in the case of a fire alarm signal, all supply fans shut down and exhaust fans turn on. I agree with the shunt trip route opposed to the contactors. Also wanted to put my 2 cents in that all electrical needs to be shut down when the local Ansul station is activated. Makes sense if you figure the foam may have some sort of electrical conductance as well as shutting off whatever appliance may be involved. I say local because the kitchens that I have done have more than one Ansul cabinet.
Watt Doctor, I was just about to post the same note, about 8 years ago, a kitchen in one of the high rise office buildings had a fire gut it, underwriter inspection showed, someone put relay in place of required shunt breaker. It failed to operate. Cost to building owner $250,000
