Controlling Access With Interlocks and Mantraps

These devices are used where only one door may be unlocked or open at one time. Unlocking or opening one door automatically secures all other doors within the designated area.

Special door control features may be required for some access control projects. The markets or geographic area you serve will have a lot to do with your activities with respect to these special projects.



Lockdown systems permit the immediate disabling of request-to-enter devices (card readers, keypads) into a defined area. Schools and universities are implementing lockdowns in order to protect students and teachers in the event of violent behaviors.

The lockdown may also involve securing the premises against egress, such as in a detention or institutional setting. Lockdown systems can be triggered from a central location, and usually it is desirable that in the lockdown can be initiated from within the protected area.

In military, government detention and healthcare facilities, control of entry and egress may be allowable, while the usual life safety rules may be suspended.

In a crisis situation, it may be required to immediately take control of all movements in or out of a facility.



Sequencers (wireless and wired) are not emergency devices but may be used for convenience and environmental purposes. For example, both low and full energy automatic door operators used in vestibules may incorporate sequencers so passage through the vestibule may be accomplished with minimum effort for the end-user.

Sequencing the doors also helps to contain environmental air, to reduce heating and cooling costs, as well as enhancing the comfort of the building occupants.



Locking or non-locking interlocks can be used in a number of situations for a variety of reasons and may involve multiple openings.

The basic operation of a two-door locking interlock is that when one of the doors is open, the other cannot be opened. Non-locking interlocks can inhibit the operation of handicapped actuators, card readers or other request-to-enter devices if a door is not closed.

When individuals are entering or leaving secured areas, an interlock may be used to enforce the proper usage of access controls so movements can be documented and controlled to prevent piggybacking or passback.

Piggybacking and tailgating occur when an unauthorized person achieves access by following and authorized person through an access point.

Passback refers to the uncontrolled, consecutive unauthorized passage through an access point. Anti-Passback prevents misuse of a security door control system by establishing a specific sequence which must be followed in order for the system to grant access and in some applications egress. For every use of a card to enter, there be a corresponding use to egress before the card can be used to enter again. The Anti-Passback rule can be applied to a single access control point or globally to all access points within a system.



In clean room environments, it may be required that the perimeter around an area be secure at all times, so an interlock will be used to create an air lock between doors. This arrangement of doors and controls are also referred to as mantraps. Mantraps may be employed where hazardous substances are being moved.

Marshals are using mantraps in order to maintain law and order at entrances to Federal Courts and buildings. In detention and institutional situations, there may be a requirement to maintain external control over prisoner or patient movement, where an interlock system will allow safe and controlled movements.

In certain settings, there will be shared facilities such as bathrooms between adjoining spaces. Interlocks can be used to afford the desired convenience and privacy to users.

Research laboratories may wish to prevent the possibility of the unintentional entry or escape of radio frequencies. Specially designed radiation-proof enclosures and doors may also incorporate interlocks so the RF seal is maintained.

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