NFPA 72 Emergency Control Functions, Elevator Recall and Protected Premises Systems
(Chapters 21 and 23)
NFPA 72-2019 National Fire Alarm and Signaling Code (DBPR CIB reference list); read in the NFPA free-access viewer 2026-09-21 · Reviewed 2026-09-21
Chapter 21 is what the fire alarm system does besides ringing bells — recall elevators, shut down fans, release doors, unlock egress doors. Chapter 23 is the building system itself: circuit classes for IDC/NAC/SLC, presignal, positive alarm sequence, alarm verification, and the wiring limits on waterflow and supervisory devices. Numbers: 3 ft, 21 ft, 24 in., 10 minutes, 1 minute, 15 s / 180 s, 0.7, 5 / 20, 1 year / 7 days / 4 hours / 60 s / 200 s / 20 s.
1. Emergency control function interfaces — 21.2
- Functions may be automatic; they never interfere with power for lighting or elevators.
- The interface device (relay/module) is located within 3 ft of the component it controls unless the control circuit is Class D (fail-safe); wiring from the control unit to the interface is Class A, B, D, N or X; the interconnection is monitored for integrity (12.6); the interface-to-equipment connection is per NFPA 70 (listed contacts, an SLC, or other listed means).
- On a life-safety network, a missed heartbeat/poll causes a trouble within 200 seconds.
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