If the primary power is disconnected, what is the minimum acceptable time for secondary power to operate the voice evacuation systems?

The minimum acceptable time for secondary power to operate voice evacuation systems is 15 minutes. This duration is critical because it ensures that in the event of a power failure, the system has enough backup time to operate effectively during an emergency situation.

Voice evacuation systems are essential for communicating evacuation instructions to occupants in a timely manner. A 15-minute backup power provision allows for extended use of the system, giving individuals sufficient time to evacuate the premises safely while still receiving real-time communication from the system.

Meeting this requirement is vital for maintaining safety standards in fire alarm systems, aligning with national codes and practices to ensure both reliability and compliance in emergency management. The other timeframes, while potentially usable in some contexts, do not meet the regulatory expectations outlined for essential safety communications in emergency scenarios.