Hold-open devices for single leaf doors

A hold-open system is a mechanism by which fire doors are held open electronically. Door leaves can thus be held in the open position until they are released, either manually or in the event of fire via the smoke detectors, and the door closes. 

A hold-open system is made up of

• A trigger mechanism (processes the signals issued by the fire alarm system)
• Fire alarm
• Hold-open mechanism (door closer with electrical hold-open or holding magnet)
• Power supply

In the event of a fire, fire and smoke doors that are being held open are closed automatically. In Germany, hold-open systems on fire and smoke doors require a general construction permit from the Deutsche Institut für Bautechnik (DIBt), Berlin.