NFPA 72 code sections · Advanced Topics: Addressable, Wireless & IoT
Listed wireless: 10 seconds to alarm, 200 seconds to notice a lost device, 7 days of battery warning
Low-power radio (wireless) fire alarm systems are permitted when they are listed and meet the special requirements of Chapter 23. An alarm from a wireless device must reach the control unit within 10 seconds. Every transmitter is supervised so that a loss of communication is annunciated as a trouble within 200 seconds. Device batteries must last at least one year, and a low-battery trouble must be sent while at least 7 days of normal operation remain. The system must identify interference that would block alarm reception, and removal of a device must cause a trouble just like a wired device.
NFPA 72 reference
Chapter 23 — Protected Premises Fire Alarm Systems
23.16 Special Requirements for Low-Power Radio (Wireless) Systems (23.18 in some editions): 23.16.2 listing; 23.16.3 alarm within 10 s, supervision of each transmitter within 200 s, 1-year battery life with low-battery trouble at ≥ 7 days remaining, interference indication
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 historic courthouse can't be re-wired without damaging plaster, so a listed wireless system is installed. During acceptance the AHJ removes a detector and starts a stopwatch: the trouble appears at 2 minutes 40 seconds — inside 200 seconds — and a pull station alarm reaches the panel in 4 seconds. The owner's ITM plan adds battery replacement at the manufacturer's interval, logged per device.
Quick check
1. A wireless initiating device's alarm must reach the control unit within:
2. Loss of communication with a wireless device must be annunciated within:
3. A wireless device's low-battery trouble must be sent with at least how much normal operation remaining?
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