Which items are considered supervisory signals on a fire alarm system?

• A. Power supply, smoke detector, and horn
• B. Water flow, OS&Y, and control values
• C. Tamper switches, bells, and strobes
• D. Water pressure, valve actuator, and signal strength

Answer: (B)

Supervisory signals indicate a monitored device or system component is not in its normal ready state and needs attention to keep the system ready to operate. In a fire alarm system, keeping tabs on valve status, water movement, and control readings helps ensure the system can deliver water when needed and that nothing essential is out of place.

Water flow is watched to catch situations where water is moving through the piping in a way that could affect system readiness—it's a non-normal condition that must be supervised. The position of the control valve (often shown as OS&Y) tells you whether the valve is open or closed, and knowing that status is critical for confirming the system can deliver water or that a valve isn’t inadvertently shut. Control values encompass the monitored readings from the system’s sensors and equipment (such as pressures or other panel values) that, if out of range, signal a condition requiring service.

In contrast, devices like smoke detectors and audible/visual notification appliances (bells or strobes) are initiating or signaling devices that trigger alarms or alerts, not statuses that require supervision.