Electromagnetic locks

               When the exit must be controlled, it is necessary to provide a fail-safe device, such as an electromagnetic lock, that will keep the door locked not only on the entry side but also on the exit side of the door.

               In the past, the installation of electromagnetic locks may have been considered to be less costly than the installation of door strikes. As a result, the market for electromagnetic locks has grown exponentially over the past few years. Unfortunately, a great number of electromagnetic lock installations were not done according to regulations and in some instances were actually jeopardizing the safety of occupants. The proliferation of electromagnetic lock installations has caused great concern amongts safety regulators and, now, stringent local regulations and site inspections are common. This has caused a substantial increase in cost of using electromagnetic locks. Because of these extra costs, the use of electromagnetic locks may be more appropriate in situations where they are the only alternative, such as locking a controlled exit door.

Regulations
               National and local building codes and fire ordinances usually regulate the use of locking devices. One must remember that these are usually minimum requirements and that the local authorities may have the last word in interpretation and exceptions. Always check with local authorities before installing any locks. Once installed, it can be quite expensive to replace the locks and repair doors and door frames.

Other locking devices
               Mechanical devices (such as electric deadbolts) that prevent free exit are usually not permitted for use in access control applications. Check with local authorities

DROPBOLT
               If the door is pushed/pulled in the direction of swing against an electric strike that is not energized, the keeper (or lip) part of the strike plate folds back and releases the latch, allowing the door to open. This device does not provide positive latching when it is de-energized.