When an electromagnetic lock is installed on a door in a means of egress, there are two options for code-compliant releasing operations. One option is for the mag-lock to be released by door-mounted hardware (and also upon power failure). The other is for the mag-lock to be released by a sensor, along with a push button, power failure, and the fire alarm system. Sometimes a system incorporating a sensor can be problematic, because traffic moving past the door can inadvertently unlock the mag-lock.
Jeff Dunham of BEA Inc. sent me these photos of a door with a sensor that was intended to release the mag-lock. The sensor has been rendered useless by black electrical tape, so the door would not unlock for egress unless the push button beside the door was pushed. It sounds like the push button may have been wired incorrectly as well, since there was a 2-second delay before the lock would release. The IBC requires the following with regard to the push button: “When operated, the manual unlocking device shall result in direct interruption of power to the lock—independent of other electronics—and the doors shall remain unlocked for not less than 30 seconds.”
Ironically, the doors were serving a room that was being used for a product liability seminar.