Locking and unlocking doors is the basic application of any access control system. The system remotely controls the lock to permit or deny access into an area. The controlled doors may be secured all the time or only during user selected schedules. To do this, electrical locking devices are linked to the door controllers provided with the access control system.
The most common locking devices used in the access control industry are electric door strikes and electro-magnetic locks. To select which locking device should be used on a specific job, the installer must begin with an evaluation that will take into account not only the security requirements, but also the regulations imposed by local or national authorities having jurisdiction.
Simple rules for most cases:
For Free Exit doors, use electric strikes. Compliance with regulations is usually easier.
Add an electromagnetic lock if you want to prevent free exit or to control exit with a card reader or a keypad. Note that you want to add an electromagnetic lock and keep the door strike (to provide physical security) if, as a result of regulations, the electromagnetic lock must be deactivated during a fire alarm signal or a building power failure.
Always check with local authorities having jurisdiction before installing any locks. Once installed, modifications of systems or removal of locks can be very expensive.
Because of potential regulations affecting the use of other devices, a door strike will generally be the most economical locking mechanism.
Always order electric strikes as:
fail locked (fail-secure) which means the strike will be locked when you remove power;
continuous duty; These specifications correspond to the requirements of access control. Electric strikes are generally more difficult to install than electro-magnetic locks and the services of a competent locksmith may be required.
If the door strike is installed on a fire rated door, it may have to be approved for such use to maintain the fire rating of the door.
On double doors, the door strike will be installed on the inactive door which should be bolted down. A door cord or electric-conductive hinge will carry the power to the strike.
It may not be possible to install door strikes on special doors such as full glass doors. The only alternative may be to install an electro-magnetic lock.
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.
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.