What is always open in a deluge system?

In a deluge system, the sprinkler heads are designed to always remain open. This is a critical feature because deluge systems are used in scenarios where rapid discharge of water is essential to control a fire, particularly in high-hazard areas. Unlike traditional sprinkler systems, which are activated by heat from a fire and only release water from individual sprinkler heads, deluge systems have all their sprinkler heads open at all times and are activated by a fire detection system or a manual trigger.

The constant open state of the sprinkler heads allows for maximum water coverage and immediate response in the event of a fire, helping to effectively suppress flames quickly over a wide area. This design also eliminates the lag time associated with individual sprinkler activation, making deluge systems very effective for certain types of fires.