NFPA 72 code sections · Fire Alarm System Integration
Magnetic door holders release on alarm — and on power loss
Smoke doors and fire doors held open by magnets have to close when they are needed. The fire alarm system releases the holders on activation of the smoke detectors covering the door opening, on any fire alarm signal where the building code requires full closure, and automatically on loss of power to the holder — fail-safe. The release circuit is an emergency control function: a listed relay or module near the holder, monitored wiring from the panel, shown on the I/O matrix and tested at acceptance and annually.
NFPA 72 reference
Chapter 21 — Emergency Control Function Interfaces
21.8 Door and Shutter Release (release on actuation of detectors protecting the opening, on fire alarm signal where required, and on loss of power); 17.7.5.6 smoke detectors for door release; 21.2 general ECF requirements
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 hospital corridor door is held by a magnet fed from a janitor's closet receptacle. During a smoke event the door stays open because the detector module controls a relay in a different closet that lost power when a cleaner unplugged a floor machine. The holder is re-fed from the fire alarm power supply through a monitored module, and a loss of power now closes the door instead of leaving it open.
Quick check
1. A magnetic door holder must release the door when:
2. Door release is treated as:
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