A locking system ensures that fire protection closures or Smoke closures are kept open in normal business operations (this means that heavy doors do not have to be opened again and again) and in the event of a fire or smoke development, the doors are automatically closed. In connection with the door mechanism, a locking system must be connected to at least one fire detector, an optical smoke detector or a smoke switch. As a rule, complete fire protection systems are used.

Door adhesive magnets are used as a locking device to hold fire protection ends when opened. They must be coupled with a smoke alarm system that switches off the holding current in the event of a fire in order for the doors to close.