NFPA 72 code sections · Wiring & Circuitry
Survivability levels 0-3: how long a circuit keeps working in a fire
Pathway survivability is separate from circuit class. Level 0 means no special protection. Level 1 is a fully sprinklered building with the pathways in metal raceway. Level 2 is a 2-hour fire-rated cable or enclosure (or a listed 2-hour circuit integrity cable), and Level 3 combines the sprinklers of Level 1 with the 2-hour protection of Level 2. Chapter 24 is where the requirement bites: a system that relocates or partially evacuates occupants — a high-rise voice system that tells floor 20 to leave while floor 5 stays — needs Level 2 or 3 so the speaker circuits on untouched floors keep working while the fire floor burns.
NFPA 72 reference
Chapter 12 — Circuits and Pathways / Chapter 24
12.4 Pathway Survivability (12.4.1 Level 0, 12.4.2 Level 1, 12.4.3 Level 2, 12.4.4 Level 3); 24.3.14 pathway survivability for emergency communications systems with partial evacuation or relocation
References use NFPA 72 2019/2022 numbering — section numbers can shift between editions, so confirm in the edition your AHJ has adopted.
On the job
A 12-story office tower uses selective (floor-by-floor) voice evacuation. The speaker risers are ordinary FPLR in a shared telecom chase. Plan review returns it: with relocation messaging, the risers must meet Level 2 or 3 — the contractor switches to a listed 2-hour circuit-integrity cable in the rated stair shaft, and the amplifiers are relocated into a 2-hour enclosure.
Quick check
1. Pathway survivability Level 2 means:
2. Which system most clearly needs Level 2 or 3 survivability?
3. Level 3 combines:
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