In which type of sprinkler system does the detection system play a crucial role before water release?

The preaction system is specifically designed to require confirmation of a fire before water is discharged through the sprinkler heads. In a preaction system, there are two triggering events needed for the release of water: the activation of the detection system and the opening of the sprinkler heads, which are typically closed until there is a confirmed fire condition. This feature is particularly beneficial in environments where water damage must be minimized, such as data centers or museums, as it prevents accidental discharge that could occur in other systems.

In contrast, the other systems do not rely on detection in the same manner before releasing water. For example, wet pipe systems automatically release water as soon as a sprinkler head is activated due to heat, without the need for an intermediate detection signal. Dry pipe systems also release water immediately following activation, but they do so from pressurized air systems rather than relying on a direct confirmation of a fire. Deluge systems are activated collectively and discharge water simultaneously when a fire detection system triggers, but they do not utilize separate detection and activation steps like preaction systems do. Thus, the preaction system's unique requirement for detection makes it stand out in this context.