Which device is used to supervise the main control valve on an automatic fire sprinkler system?

• A. Tamper switches
• B. Water flow device
• C. OS and Y valve
• D. Outside horn and strobe

Answer: (A)

Tamper switches are used to supervise the main control valve because they provide a status signal to the fire alarm system whenever the valve is moved, opened, or closed. This ensures the system is aware if the valve has been tampered with or if it is not in its intended position, which is critical for maintaining a reliable water supply to the sprinklers. The valve type itself (OS&Y) describes how the valve looks and operates, but it isn’t a monitoring device. A water flow device detects actual water movement in the pipes, not the valve’s position. Outside horn and strobe units provide audible/visual alarms but don’t monitor valve status.