Question:
Had a rather bizarre occurence tonight in a venue. Just put a pair of strobes up on the rig to use for a lightning effeect, nothing serious. testing the strobes to find a decent trigger time for lightning the fire alarm went off - ok, nothing wrong there. evacuate bulding, when allowed back in went back to sorting strobes out - alarm goes off again. Town halls caretaker comes in and tells us something we are doing is setting the fire alarms of - fire pannel was showing heat had set off the detectors (there some form of beam type detectors). Nothing we were using was generating much heat so put it down to a fault. used the strobe again - lo and behold the fire alarm went off again. rather strange. Anybody else ever found that they have set fire alarms (detector beam type) off with strobe lighting??

Answer: Certain types of fire detectors are basically photocells that only detect certain frequencies of light ( IIRC, the frequencies emitted by burning carbon ) and use a bit of processing to decide if the light detected is a fire or not. So it is possible. Until this issue is fixed, all strobes need to be banned from this venue. The detectors need to be changed to ones that are not set off by strobe lights.