What is one requirement for fire alarm systems regarding battery backup?

Fire alarm systems are designed to ensure life safety and property protection even during power outages. Therefore, having emergency power is essential for maintaining the operational integrity of the system. This requirement ensures that the fire alarm system can continue to function and provide alerts during a power failure, which is critical in a fire emergency where timely notifications can save lives.

The necessity for emergency power typically includes battery backups, allowing the system to remain operational, alert occupants, and coordinate with emergency services until power is restored or emergency personnel can take over. This is in compliance with NFPA 72, which emphasizes the importance of having reliable power sources for alarm systems to ensure their effectiveness in emergencies.

In contrast, options that suggest functions without battery backup or do not require any backup power miss the core principle of maintaining fire alarm operability during critical times.