Everyone has seen the part of the Die Hard movie where John McLean uses a plastic lighter to set off a sprinkler system in a building to evade capture from the bad guys? I am often asked; ‘Can this really happen in a home with a residential style sprinkler system’?
Thanks to Hollywood, most people believe that you could activate every sprinkler in an office building by pulling a fire alarm switch, shooting one sprinkler head or holding a cigarette lighter up to one sprinkler head. Fortunately, that is not how automatic fire sprinklers work. While it is possible to activate ONE sprinkler head with a cigarette lighter, the sparks from a sword fight will not turn the parking garage at Madison Square Garden into a flood zone!
Residential systems are different; Residential Sprinkler heads are designed to discharge at a preset temperature and can be protected from any tampering by a cover plate. It would be difficult to set off such a head with a butane lighter. There is a small vial of glass within the head that bursts when heated to a temperature that would exist if there were a sizable flame on the floor below. In fact, residential sprinklers in new homes are designed to go off independently. The head (or in some cases 2 heads) will go off closest to the heat. New homes do not have a ‘deluge’ system where all heads go off simultaneously, nor can they be set off by a smoke detector. The Home Fire Sprinkler Coalition has a great website to show how sprinklers work (Click here to view that link).
It is also important to note that residential sprinklers are not set off by smoke. My sunday morning burning toast may set off the smoke detector, but not the sprinklers!
Dear John: although you are probably one of my favorite characters in a movie, your little distraction would probably only work in a high-rise.
Yippie kai yay!