What system holds back water from the piping and is triggered by a separate fire detection system?

The system that holds back water from the piping and is triggered by a separate fire detection system is the preaction system. This system is specifically designed to enhance the safety and effectiveness of fire protection in environments sensitive to water damage, such as data centers or art galleries.

In a preaction sprinkler system, the water is not immediately released into the piping; instead, the piping is filled with air. This system employs a fire detection component, such as smoke detectors, to sense a fire condition. Once the detectors activate due to the presence of smoke or heat, a signal is sent to open a valve, allowing water to flow into the piping. Only once water is present in the pipes will the sprinklers activate if a fire has reached a point where the heat level triggers the sprinkler heads. This two-step procedure reduces the potential for accidental discharge of water and helps mitigate water damage while ensuring the system is ready to react promptly to a legitimate fire event.

In contrast, other systems like wet, dry, or deluge each operate under different principles and do not employ the same mechanism of delaying water presence until a fire condition is confirmed.