Only the sprinkler closest to the fire will activate, spraying water directly on the fire. Ninety percent of fires are contained by the operation of just one sprinkler.
Home fire sprinklers are technologically very advanced, but the basic way they work is very simple. Fire sprinklers have no moving parts and act simply as a water plug that releases at a particular temperature.
A residential fire sprinkler system is basically maintenance free. The only testing required on a regular basis is opening the drain/test valve to check the alarm operation. The rest of the system is designed to operate properly for 20 years or more without any maintenance. Some basic precautions to safeguard your fire sprinkler system are:
Avoid painting or otherwise covering the fire sprinkler devices, as that will affect their sensitivity to heat.
Do not hang decorations, plants or other objects from the sprinkler or piping.