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.
