How does a sprinkler head work?
In the movies, it’s a common trope to see a huge explosion of sprinklers go off in a commercial building when there’s a fire.
The implication is that, if one sprinkler head goes off, all of them go off, creating a huge mess even when the fire itself is relatively contained.
It makes for cool cinematography, but this really isn’t how sprinkler heads function in real life.
Most sprinkler heads are individually temperature-controlled, meaning that each head will only go off and allow water to flow if the temperature passes a certain threshold.
Most modern heads achieve this individual control through the use of a frangible glass bulb inside the head itself.
Inside the bulb is a tiny bit of liquid and an even smaller bubble. When heat increases, the liquid expands and the vapor compresses, breaking the bulb.
When the bulb breaks, the water inside the supply line releases and, the vast majority of the time, puts the fire out and restricts it to the initially effected area.
Pretty cool, right?