a good friend is a broadway level stage manager and often has to get permits for special events. i asked her about this and she wrote this back - maybe its moot by now but here it is and in any case if you guys have more questions i can certainly go to her again.
I have certainly pulled generator permits for special events. These tend to be for the larger, curbside, truck mounted generators. I am not sure what kind of permit is required for one of the small red personal generators. I have heard recently if you have less than 1 gallon of gas you don't need approval or a permit BUT I cannot find this anywhere in writing. I assume this is what all of the street food vendors do. I also know they frown on refueling on site and also on storing additional fuel. If you gather the info for each generator: type of fuel (diesel or gas), power (kw usually), name brand and call FDNY and ask them about what you need for that for 'an event' they might give you more details. I couldn't say how the rules might change for a demonstration though. If you do find you need a permit, put all of the above info re fuel, etc plus a sponsor organization name and address, generator arrival and departure, location of generator, and expect usage time (could say continuously) in a fax. Find out who to address it to (call the phone numbers below but NOTE these numbers may not get you to the right person on the first try - say 'you want to find out about generators for special events in lower Manhattan' then if they are going to transfer you ask to what number in case you have to call back and to whom - get a name.) and what the fax number is. Then you fax it and call back the next day to speak to the person. Ask them if they have received it and if so, what the next step is (ie do you go pay and pick up or were you denied). If you are denied, find out why. Ask where the rules are listed. You can find the FDNY fire code online. I have not read it but maybe check that out first - what is allowed. What is within your right. A generator permit for a large, event, diesel generator is $125. Smaller, gas generators *I believe* just require notice/permission but there is not a cost associated. But... Going down the permitting road is a slippery slope. Technically you need a permit to hold a demonstration and/or have a gathering of more than 20 people in a park. You need a permit to have amplified sound (speeches, radios, etc). You need a permit to march up a street. Resource on permitting:http://www.nyc.gov/html/cecm/html/home/home.shtml
Gaseous Fuel Permit Fire Department New York City Phone: (718) 999-0320 or (718) 999-1007
Generator Permit Fire Department New York City FDNY Generator Notification: Portable, Truck-mounted or any other kind of generator Phone: (718) 999-0320 or (718) 999-1007