Electromagnets for hold-open systems
Regulations which apply allow fire and smoke check doors to be held open for a limited period of time by electromagnetic hold open devices which, in the event of a fire or smoke, are de-energised to release the door so as to enable automatic closing. They operate on 24Vdc supplied typically via a triggering device such as a fire panel located within the building.
Manual release
It must also be possible to manually release any hold-open device. According to the applicable guidelines for hold-open systems, a manual release pushbutton is necessary when employing electromagnets in such applications. The pushbutton employed must be red, carry the wording “Close door”, be located in the immediate vicinity of the door, and must not be hidden when the door is in its hold-open position.
