What type of valves should control the supply of a fire sprinkler system?

In a fire sprinkler system, the primary role of indicating valves is to show the position of the valve (whether it is open or closed) and allow for easy identification during an emergency. These valves are crucial for ensuring that the fire suppression system can be effectively operated by the fire department or on-site personnel. Their design typically includes visual indicators or flags that provide a clear signal about the valve status, which is essential during high-pressure situations where time is critical.

While isolating valves can be used to shut off water to specific sections of the system for maintenance or repairs, they do not provide the same clarity of indication as indicating valves. Check valves are used to prevent backflow in the system, and ball valves are a type of isolating valve that allows for a quick shut-off. However, these options do not fulfill the critical function of clearly indicating the operational status of the system as indicating valves do.

Thus, indicating valves are the optimal choice for controlling the supply in a fire sprinkler system, ensuring that the system remains functional and that firefighters have the necessary information to act swiftly in an emergency.