Electrical door surveillance is the simplest way of providing a deterrent against misuse of escape routes. In this system, the escape door is not locked in the direction of escape, but the door status is monitored.
A door contact monitoring device can easily detect if a door is being misused and then trigger an optical and audible alarm. In networked systems the alarm is also activated centrally. A pre-alarm function can be included when locks are combined with a handle monitoring system.
Compared with electrical locking systems on doors along escape routes, having only a door monitoring system is less of a deterrent against misuse. Most fire or smoke protection doors can also be retrofitted with such a system without losing certification, provided the system is limited to a door contact being installed on the door (e.g. magnetic contact).