GG, typically, everything under the hood (gas and/or electric appliances, hood lights, and make-up air fan) must shut down, and the exhaust fan must come on, regardless of fan switch positions.
Also, either a horn/strobe or a building alarm must sound. Additionally, in some places, the gas must shut down even upon manual exhaust-fan shut-down, unless a T-stat or an LP bypass is used.
Gas solenoid valves also require a latching relay control for restoring the gas flow. The rules vary a bit in different jurisdictions, so check with the authority who will be enforcing the requirements.
PM me for my phone number if you'd like more specific help.
Well good luck, and get the local code. Here in mass you have to tie a gas solenoid valve, the hood fan and two CO detectors into the system. I love to see the EC who is asked to help on this and does not know what the deal is. I normally get asked to help finish it out. Its not hard, as long as everything is installed correctly.
Of course this is in restaurants, not computer rooms. Those have abort and manual dump switches.
Generally all heat producing appliances under the hood and the make up air must shut off on activation with the exhaust turned on. A notification (alarm)device must activate when the ansul system is activated and if there is an alarm system in the building it must activate. Also the hood must turn on automatically when heat appliances are used. These requirements are found in NFPA 17, IBC and IMC and in other codes as well.