I have worked in a few spaces like that. They laser is actually there to detect smoke. I was doing a ballroom type thing that had them and one of the decorators let go of some balloons and it just so happens balloons rise just like smoke, and it tripped the laser. Another space had a few in their grid, and we were hanging some new loft blocks and one of the people on the crew got their shoulder in the way and had the evacuate the entire building. But then again you do get to see the big red truck come!I was doing a Nike gig in Hollywood Florida. We're loading in this giagantic video screen, huge deck, tons of lights.... All of a sudden the fire alarm goes off. Evacuate, evacuate, Sounded kinda like a Dalek from Dr. Who. Anyway we found out later that the culprit was one of the rigging guys. The hotel had a fancy schmancy new fire alarm installed. It used lasers, frickin lasers man, < best dr. evil voice>. Anyway apparently you cant get within 9 inches of the ceiling or you break the beams on the lasers and it sets off the smoke dectectors. What a worthless system in a multi-use ballroom.
Dry ice gives off nothing but CO2 though, which immediatly sinks to the floor. Shouldnt set anything off. the lasers though, ive heard of them. We toured one of the histroical places round bout here with the fire dept. not long ago after they did a multimillion dollor upgrade. from what i gathered the lasers are so precise that they will sense a change in their refraction through the air cause by a change in temp. Supposedly really senstive and very hard to fool, unless someone breaks the beam. Good for museums and the like though since their considered to be dual purpose fire and burgular alarms. pricy though!The dry ice probably set off the alarm because of the particles in the air. You can itch and complain about these systems, but they're doing what they are designed to. If you know that there's a chance you might be tripping on of these alarms on accident, you might want to give your fire chief or central dispatch a call a head of time.
Allow me to explain this...Dry ice gives off nothing but CO2 though, which immediatly sinks to the floor. Shouldnt set anything off.
I'm sure you know this already, but if you're using flash powder make sure you have the local Fire Marshall come out and inspect exactly how you will be using it, as well as have stage managers on both sides of the stage with appropriate fire extinguishers. The Fire Marshall will also be able to tell you whether the flash powder will be a concern in terms of the fire detection system.I hope flash powder doesn't set off the fire alarm. That would stink since this is the first show in this theater.
All commercial CO2 foggers either my father or I have come across use the CO2 to cool vaporised heavy fog fluid. Our big fogger uses an air-con unit to cool it.Dry ice gives off nothing but CO2