Why are "flow-switch" devices used in sprinkler systems?

Flow-switch devices are utilized in sprinkler systems primarily to automatically detect the flow of water within the system and trigger alarms or activate specific system responses. When a sprinkler head operates due to heat from a fire, water begins to flow through the pipes. The flow-switch senses this movement of water and, upon detection, sends a signal to the fire alarm control panel or other monitoring systems. This prompt response ensures that alarms are activated, notifying building occupants or authorities about the presence of a fire incident.

The other options, while related to sprinkler systems, do not accurately describe the primary function of flow-switch devices. Regulating pressure is managed through separate components, temperature measurement is accomplished by heat sensors, and controlling the supply to individual sprinklers is achieved through different types of valves and controls unrelated to the detection of water flow. Therefore, choosing the answer that designates flow-switch devices for detecting water flow and triggering alarms correctly identifies their vital role in fire safety systems.