A man trap consists of two doors on either end of a vestibule. With man traps, the doors are electronically locked, and only one door can be opened at any given time. Because of this, unauthorized users can not gain entry by simply “tail gating” or following an authorized user. As secure as this is, it requires addressing certain life-safety issues.
For example, if a fire occurs inside the building, there needs to be an override enabling both doors to open and let people exit freely. Usually, there is an emergency door release on the inside which unlocks both doors, and one on the outside which unlocks only the outer door. Ensuring compliance with local code authorities is very important before setting up a man trap. In fact, fewer and fewer districts are allowing the any type of man traps installations in their buildings; so be sure to do your homework before having a man trap installed.
For more information about man traps and other access control topics, please check out Thomas L. Norman’s book “Electronic Access Control”.