Which statement best reflects the required minimum hours for non-alarm operation of a standard fire alarm secondary power supply?

Which statement best reflects the required minimum hours for non-alarm operation of a standard fire alarm secondary power supply?

• A. 12 hours
• B. 18 hours
• C. 24 hours
• D. 36 hours

Answer: (C)

The main idea is how long the fire alarm system must run on its secondary power source when the normal supply is lost and no alarms are active. For a standard fire alarm, the required minimum standby (non-alarm) duration is 24 hours. This means the secondary power supply, typically a battery, must be able to keep the panel and its normal monitoring functions operating for a full day without mains power. This ensures continuous supervision, fault indication, and readiness to respond if conditions change, while the system remains safe and detectable during a power outage. The other options don’t meet the standard: they’re shorter than the required 24 hours (or longer than the defined minimum, which isn’t the prescribed minimum).

The main idea is how long the fire alarm system must run on its secondary power source when the normal supply is lost and no alarms are active. For a standard fire alarm, the required minimum standby (non-alarm) duration is 24 hours. This means the secondary power supply, typically a battery, must be able to keep the panel and its normal monitoring functions operating for a full day without mains power. This ensures continuous supervision, fault indication, and readiness to respond if conditions change, while the system remains safe and detectable during a power outage. The other options don’t meet the standard: they’re shorter than the required 24 hours (or longer than the defined minimum, which isn’t the prescribed minimum).