The secondary power supply for in-building fire emergency voice/alarm communications must operate under quiescent load for at least how many hours?

The secondary power supply for in-building fire emergency voice/alarm communications must operate under quiescent load for at least how many hours?

• A. 6
• B. 12
• C. 24
• D. 48

Answer: (C)

When the building loses power, the emergency voice/alarm system must keep running in its idle state, delivering power at the standby (quiescent) level. This quiescent load is the normal, non‑alarm current the system draws while idle. The backup/secondary power supply is specified to sustain that standby operation for twenty-four hours, ensuring the system remains able to function during extended outages or delays in restoring power. Shorter durations wouldn’t guarantee readiness for longer outages, and longer durations would require more battery capacity than necessary.

When the building loses power, the emergency voice/alarm system must keep running in its idle state, delivering power at the standby (quiescent) level. This quiescent load is the normal, non‑alarm current the system draws while idle. The backup/secondary power supply is specified to sustain that standby operation for twenty-four hours, ensuring the system remains able to function during extended outages or delays in restoring power. Shorter durations wouldn’t guarantee readiness for longer outages, and longer durations would require more battery capacity than necessary.