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If a fire alarm control panel, burglar alarm control panel, or similar emergency system is triggered, it will cut electrical power to the electromagnetic door holders under its control. The door holders release, allowing the doors to close automatically using door closers. [1] [2] The electric power to keep the doors open is typically 12 VDC ...
The standard details requirements for a range of alarm systems including central station burglar alarms, police station connected alarms, local alarms, proprietary systems, holdup alarms, and digital alarm communicator system units. It also covers power supplies essential for burglar-alarm equipment operation.
Many exit control locks are based on magnetic locks. One type, delayed egress magnetic locks, will not allow the door to open immediately. This allows a guard to get to the door before the door opens. It will also release if there is a fire alarm or power failure, but otherwise these locks hold the exit doors shut. These units are common in ...
The first modern direct-pull electromagnetic lock was designed by Sumner "Irving" Saphirstein in 1969 [6] [7] [8] for initial installation on doors at the Montreal Forum. [9] Fire concerns by local authorities in locking the doors at the Forum prompted management to find a locking solution that would be safe during a fire incident.
Depressing the bar unlatches the door, allowing occupants to quickly leave the building. [3] Modern fire standards often mandate that doors be fitted with crash bars in commercial and other occupancies where mass evacuation may be slowed by other types of door openers. They are sometimes intended solely for emergency use and may be fitted with ...
Electromagnetic fire door holders may also be hard-wired into the fire panel, radio-controlled, triggered by radio waves from a central controller connected to a fire panel, or acoustic, which learns the sound of the fire alarm and releases the door upon hearing this exact sound. [20]
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This is exactly the same principle as a child safety door lock which is installed on car doors. Electric strikes on AC allow someone outside the door to hear when the door is open. The buzzing noise is typically made by applying alternating current (AC) to the strike instead of direct current (DC). When using a DC powered strike, the sound is ...