A hold-open system (FSA or TFA) can keep the door leaves open during normal operation and closes them after pressing a hand button or in the event of a fire, triggered by a fire detector. It is used when a door element should or must be open at least temporarily due to its use, e.g. for the transport of goods, but a self-closing door is required by building regulations. In this case, hold-open systems are provided so that users do not engage in inadmissible (and punishable) manipulation of the locking mechanism.
Hold-open systems in the form of a correspondingly approved extended overhead door closer with integrated hold-open (e.g. in the slide rail) and integrated smoke detector are widespread. However, they are also available as separate electric holding magnets that are combined with conventional door closers and keep the door open. The approval regulations must allow the combination of all individual products (holding magnets, door closers, buttons and smoke detectors) with each other. Hold-open systems require an electrical connection, as the closing process is triggered electrically (via hand switches or automatic smoke detectors). When using hold-open systems on double-leaf doors, it must be ensured that the stationary leaf closes in front of the opening leaf by means of a so-called closing sequence control in order to prevent the door rebates from tilting and thus the door element from closing completely.
Source: bauwion
