The secondary power supply capacity for supervising station facilities and equipment shall be capable of supporting operations for a minimum of _________________.

The requirement for a secondary power supply capacity for supervising station facilities and equipment to support operations for a minimum of 24 hours is largely based on the need for reliability and safety in critical situations. Fire alarm systems must remain operational during emergencies, such as power outages or natural disasters, which may extend beyond short periods of disruption.

A 24-hour duration ensures that the system can function adequately for an entire day without external power, allowing for effective monitoring and response during emergencies. This duration aligns with industry standards that prioritize maintaining system integrity and communication capabilities over longer interruptions to allow for appropriate emergency responses.

In addition, specifying a minimum duration of 24 hours gives time for responders to address the situation, and it covers substantial time frames that are commonly anticipated for power restoration in many scenarios.