Hold-open devices are apparatuses or apparatus combinations that are fit to gracefully inactivate the functions of closing means. In case of reaction of a related release device in case of fire or during alternative release open shutters are automatically closed by the closing means.
A hold-open device consists of at least one fire detector, one release apparatus, one hold-open mechanism and a power supply.
The hold-open device must prove its suitability for the employment as part of track-bound conveyor systems by a general building inspectorate approval with No. Z-6.5-1705.