One thing that really drives me nuts in movies is situations where a character needs to set off a fire alarm to create a distraction or something for him to get away or set of whatever his plan is. So he usually gets a lighter or starts a small fire or something to set off a fire sprinkler.
Now, setting off a fire sprinkler may be enough to set off a fire alarm once the system detects the change of pressure in the line but what it will not do is set off every single other fire sprinkler in the building! Fire sprinklers do not work that way. They only go off in the areas where there is actually fire because there is a piece of wax between the outlet of the sprinkler and it's body. Heat melts that wax.
If all of the sprinklers did go off by just one's wax melting there wouldn't be enough water pressure in the system to effectively extinguish the fire.
Now, setting off a fire sprinkler may be enough to set off a fire alarm once the system detects the change of pressure in the line but what it will not do is set off every single other fire sprinkler in the building! Fire sprinklers do not work that way. They only go off in the areas where there is actually fire because there is a piece of wax between the outlet of the sprinkler and it's body. Heat melts that wax.
If all of the sprinklers did go off by just one's wax melting there wouldn't be enough water pressure in the system to effectively extinguish the fire.