Steam FX

[spong8]

One way that we made steam effects is through the use of a pnumatics mixed with a fog machine. Basically we had a fog chamber where the fog machine pumped into. We had pvc pipe that lead from the box of fog and had drilled holes through and through the pipe where we wanted steam to appear. One was only large enough to fix an air nozzle to, the other was slightly larger, where the fog would exit. Basically when we fired the air it created a vaccume in the pvc which syphoned the fog out of the chamber and out of the hole in a whispy way.

You could use this at a simpler scale as well by using ducting and hoses. The trick IMO would not have a fan directly syphoning on the supply of fog but allow it to naturally make its way to the fan as it blows. I think the principle being used is air moving from a low pressure to a high pressured area. Highpressure being the air being blown by the fan.

 

[len]

Any atmospheric CAN activate a fire alarm. But it's impossible to say that a particular unit or type of atmospheric will trigger the alarm after X minutes. It depends on the output, airflow in the building, the type of alarm, how it is set, etc.

If you use an atmospheric (fog/haze), I'd find a way to control the building/space HVAC and turn the fans on to run constant during the show. It may get a little chilly, but you can turn up the temp a degree or two to compensate. Having the building hvac fans running constantly will help push air through the filters and decrease the particulate in the air. I don't think an off-the-shelf humidifier or 2 will give you the forced look you want. Remember that those steam trunks in big cities push the steam at over 70 mph, so there's a good deal of force behind them. A good hazer/fogger that can be vented to point up through the hole in the stage is probably the best bet. But I'd go with haze because most foggers are noisier.