An automatic sprinkler is a fire-suppression or fire-control device with a heat-activated element. The sprinkler operates automatically when the air temperature rises to or above the device's specified temperature rating. When that happens, the sprinkler discharges water over a specified area.
1 – Heat from the fire causes the glass bulb to break
2 – Cap releases
3 – Water releases onto the diffuser
4 – Water puts out the fire