What must accompany the reserved power supply for the extinguishing system?

• A. Manual backup switch
• B. Battery indicator
• C. Audible alarm only
• D. Monitored supervisory alarm

Answer: (D)

When a forced extinguishing system relies on a reserved power supply, it must be continuously watched for faults. A monitored supervisory alarm provides that ongoing oversight by signaling any problem with the backup power—such as a voltage drop, failure, or disconnection—to the fire alarm control system or supervising personnel. This ensures the system will actually operate during a power outage and that maintenance or repairs can be prompted immediately if the backup power isn’t healthy.

Other features don’t give this level of reliability. A manual backup switch is just a way to activate the backup manually and doesn’t tell you when the reserve power is failing. A battery indicator shows battery status but not the overall health or operability of the power supply tied to the extinguishing system. An audible alarm only warns occupants and doesn’t provide supervisory feedback about the power supply’s condition to the monitoring system.