TV and Movie BS

My number one pet peeve with TV and Movies has got to be the portrayal of fire suppression sprinklers in buildings.

Lets get this straight right now! STUPID TV LISTEN TO ME!!!

If you take a torch or other heat source to a sprinkler that sprinkler and ONLY that sprinkler will trigger. It will NOT trigger the whole damn building to dump water everywhere. First off, how the hell could that happen? A sprinkler is triggered when a low temperature material melts and opens a valve. That happens ONLY on that valve. Secondly, why the hell would an entire building trigger? The idea of a sprinkler is to put out a fire. There is a finite amount of water pressure in a sprinkler system, if you open every valve in a system the pressure would drop and very little water would get to the area that needs it.

* edit: 5/17 *

As a few people have pointed out to me, it triggers the zone, and that makes perfect sense. However my point was more that it triggered the entire building… on multiple floors…