maglock

An electromagnetic lock, magnetic lock, or maglock is a locking device that consists of an electromagnet and an armature plate. There are two main types of electric locking devices. Locking devices can be either "fail safe" or "fail secure". A fail-secure locking device remains locked when power is lost. Fail-safe locking devices are unlocked when de-energized. Direct pull electromagnetic locks are inherently fail-safe. Typically the electromagnet portion of the lock is attached to the door frame and a mating armature plate is attached to the door. The two components are in contact when the door is closed. When the electromagnet is energized, a current passing through the electromagnet creates a magnetic flux that causes the armature plate to attract to the electromagnet, creating a locking action. Because the mating area of the electromagnet and armature is relatively large, the force created by the magnetic flux is strong enough to keep the door locked even under stress.

(wikipedia.org)

In 2009, IBC included a new section called “Electromagnetically Locked Egress Doors”.

Section 1008.1.4.4 basically states that when a maglock is used, two other devices need to be installed:

1)A Request-to-Exit Motion (REX)
2)An auto-resettable emergency push button that is NOT tied into the access control system but wired directly to the lock

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DayCare Information Life Safety International Building Code

“Do we have to use the motion detector?”

Yes, the motion detector “sees” someone approaching and unlocks the door so that there is no “thinking” exiting the building. There should never be any special or secret knowledge to leave a facility.

“If you put in that motion detector, a child could leave through that door!”

Correct, as there should never be any special or secret knowledge to leave a facility.

“We already have an exit button”

Many access control systems have exit buttons, but unfortunately, these buttons are tied into the access control system; if the system malfunctions, so does the button. The reason that the code states “independent of the access control system electronics” is to avoid a malfunction in such a manner. It’s very important to verify the button installed is correct.

1008.1.4.4–Access-controlled Egress Doors

•applies to entrance doors in a means of egress and entrance doors to tenant spaces;

•allowed in Use Groups:

– A (Assembly);

– B (Business);

– E (Educational);

– I-2 (Institutional–Hospitals and Nursing Homes);

– M (Mercantile);

– R-1 (Residential–Hotels, Motels, and Boarding Houses); and

– R-2 (Residential–Apartments and Dormitories);

•a sensor must be mounted on the egress side to detect an occupant approaching the doors (doors must unlock upon a signal from the sensor or loss of power to the sensor);

•loss of power to the lock must unlock the doors;

•ready-access manual unlocking device (e.g. push-button) results in direct interruption of power to the lock, independent of the access control system electronics (when the push button is actuated, the doors must remain unlocked for at least 30 seconds);

•push-button must be located 1016 to 1219 mm (40 to 48 in.) vertically above the floor, within 1.5 m (5 ft) of the doors, and accompanied by signage stating, “Push to Exit;”

•if the building has a fire alarm/sprinkler/fire detection system, its activation must automatically unlock the doors until reset; and

•entrance doors in buildings with occupancy in Groups A, B, E, or M shall not be secured from the egress side during periods the building is open to the general public.