Electromagnetic (maglock) locking systems have existed for several decades. One of the best features of maglocks is that there are no moving parts. Once installed, unless there is an extreme shifting and misalignment of the door and frame, maglocks will do their job for a long period of time.
Maglocks soon became a popular locking system after their first introduction. The units are normally mounted at the top of the door and out of normal view as compared with most other electronic locking systems such as electric strikes. There were fewer regulations regarding maglocks years ago and in some cases little thought was given to life safety consequences and maglocks were improperly installed in some situations.
One of the questions surrounding maglock installations involves how to unlock a door which is locked by a maglock. At one time the city of Chicago required a mechanical disconnect for locking devices. Since a maglock is held in a locked position by electric power, the only way to unlock a maglock is by disconnecting the power. Chicago has reportedly relieved some restrictions against maglocks. National building codes now provide better direction for maglock usage and current electromechanical locks and accessories are designed to conform to these rules. Before proceeding with any maglock installation it is always best to consult with the local authority having jurisdiction (LAHJ).
Maglocks are useful for both security and for movement control of pedestrians. Maglocks can be used in instances where other access control devices may be difficult or impossible to apply. Swinging or sliding doors, overhead doors and fence gate doors are just some of the instances where maglocks may provide the simplest access control solution.
Holding force is a consideration whenever a maglock is installed. In traffic control situations a 600 lb. holding force is usually sufficient. Security rated maglocks in the 1200 lb. holding range are normally used for security applications. Higher holding force maglocks are available. The amount of holding force can affect the size of a maglock and the current consumption.
Several factors affect the holding force. Correct voltage, proper alignment of the lock and armature and corrosion or foreign material on the surface of the magnet or armature will all affect proper operation. As a consequence, the holding force of a maglock may decrease after an extended period of time. Use of a maglock with a higher holding force can provide an added amount of security.
Doors and frames must always be inspected whenever a maglock installation is considered. Generally a maglock is mounted at the top of a hinged door. Since the pull or push handle is centered near waist height, the door must be rigid enough so it will not flex when someone tries to open the locked door. Most doors open towards the direction of egress. If an opening contains an exit sign and opens inward, installation of a maglock may just be adding to a code compliance violation. If the door is code-compliant, a maglock can be installed on either an outswinging or inswinging door by using the proper accessories.
Flat surface area on the header and door frame must also be checked to determine if there is enough space for a maglock installation. Maglock systems are also available for installing on vertical door jambs but this will narrow the door opening dimension and may affect the ADA width requirement of 32 inches. ADA height regulations require an 80 inch opening and may also prevent the installation of a maglock on the top door frame.
Maglocks have two primary parts, the magnet and the armature. Magnets (the maglock) is usually attached to the door frame. The armature is usually attached to the door. If the door is of solid wood or metal construction, drilling a single hole through the door for a sex bolt armature retainer is usually not a problem. Herculite doors or aluminum doors with very narrow top rails may not have an area suitable for drilling a cross-bore hole for the sex bolt. Accessory brackets are usually available for these special applications.
Maglock wiring basically consists of two wires to energize the electromagnet. Modern maglocks now contain many additional options. A door status monitor can signal when the door is left ajar. A bond sensor can signal a firm bond (locked position) between the armature and the electromagnet. A timer can be set to delay relocking of the maglock. A motion sensor can detect movement of a person walking towards the door and can automatically unlock the door for egress. Most life safety codes require an REX (request to exit) sensor for automatic unlocking for egress. A delayed egress function can be used to prevent immediate unlocking in cases such rear hidden exit doors in commercial stores or at mental health facilities.
Although not directly attached to the maglock, a power supply, usually of 24 volts, is required to provide power for the maglock. A manual push-to-exit button is often required as a fail safe feature in case of a motion sensor failure. According to customer requirements and the security situation, an electromechanical lock system can be the best possible solution.
