This seems like a good place for a little anecdote that has been floating around our
theatre for quite a while. We have six
Altman Q-Lites hanging on our electrics that we use as work lights. (They're on whenever anyone is in the
theatre.) One day during lunch one of those pipes was at floor
level because the techies were adjusting the other instruments on the
batten for a show. The lunch bell caught the techie in charge of the effort, and he hurried off to his next class without flying the pipe back to
trim. Nobody came in the room for about three hours, and when someone finally did, the 100W Q-Lites had burned 6" holes in the
marley beneath, completely ruining a whole sheet of
marley. The instruments were at least 30" away from the floor at that time.
Keep in mind, this is direct light, pointed straight at the floor, and those suckers get really toasty. We're lucky this little gaffe didn't set the place on fire.
This shouldn't happen with most instruments, though. The
Q-Lite is one of the hottest things I've ever worked with. While
Altman ellipsoidals take about 5-10 minutes at full before they're too hot to touch, the
Q-Lite reaches that
level almost instantaneously. I was amazed when I found the wattage on the site I linked to above. I had thought that they used at least 500 watts, but it's only 100.