How long must secondary power supplies for fire alarm systems support standby operation?

The requirement for secondary power supplies in fire alarm systems to support standby operation for 24 hours is based on industry standards, including those set forth by the National Fire Protection Association (NFPA). The reasoning behind this 24-hour requirement is to ensure that, in the event of a power outage or failure, the fire alarm system remains operational long enough to adequately respond to emergencies and alert occupants.

This duration allows for the possibility of extended electrical outages, ensuring that the system can maintain functionality not just during the initial power loss but also during potential recovery times before primary power is restored. Maintaining a fully functional fire alarm system during this period is crucial for safety and emergency response efforts.

The other durations presented (12 hours, 36 hours, and 48 hours) do not align with the standard safety protocols outlined for fire alarm systems. While having longer durations might sound beneficial, the established 24-hour requirement strikes a balance between practical operation time and the capability of the equipment.