In a combined dry-pipe/preaction system, if the heat detection system fails, how will the system operate?

In a combined dry-pipe/preaction system, the function of the heat detection system is critical to its operation. When the heat detection system fails, the system defaults to its design characteristics as a dry-pipe system. This means that the system remains filled with pressurized air, and the water does not flow into the piping until an activation event occurs, such as the opening of a sprinkler head or manual activation.

In the absence of a functioning heat detection system, there is no signal to the valve to allow water into the system, preserving the dry environment that is typical of dry-pipe systems. The design of dry-pipe systems aims to prevent accidental water discharge, which is particularly important in areas where water damage could be exacerbated, such as unoccupied spaces or areas with sensitive equipment.

The other options represent different types of systems with distinct operational characteristics. A preaction system typically requires both heat detection and additional action (like a sprinkler activation) to flow water. A deluge system involves a fully opened valve that allows water to flow into all connected sprinklers simultaneously, which would not apply here. A wet-pipe system, on the other hand, means the pipes are constantly filled with water, which is not the case when relying