Two-hour protection of circuits as a survivability level corresponds to which level?

• A. Level 0 survivability
• B. Level 1 survivability
• C. Level 2 survivability
• D. Level 3 survivability

Answer: (C)

Survivability levels describe how long critical circuits must stay powered and usable during adverse conditions like a fire or power loss. Two-hour protection means the system is designed to keep essential circuits running for at least two hours. This level is chosen to provide a reliable window for detection, signaling, and control to function while the building is being protected or evacuated, using features such as redundant power feeds, sufficient battery backup, and separation from nonessential loads. Level 2 is the middle option in the range, longer than Level 1 but shorter than Level 3, which is aimed at even longer protection. Level 0 provides no survivability for circuits. So two hours aligns with Level 2 survivability.