An ancillary function of many fire alarm systems is the automatic closure of fire doors in the event of a fire. On larger systems, however, it is not always practical to globally shut all of a building’s fire doors, particularly if the fire is consigned to a distant, secure area. With this in mind, in addition to demanding the installation of a standard fire alarm system, an increasing number of specifications are also calling for independent, self-contained door release systems sited locally to each set of fire doors. C-TEC’s BF375PEK is one such system. The system includes a compact 24V 250mA double gang power supply featuring an on-board detector circuit, two optical smoke detectors and bases and one electromagnetic door retainer. In normal conditions, the power supply energizes the door retainer to hold the fire door open. On each side of the door, a smoke detector is installed. Should one or more of the detectors go into alarm, the door will close. For added protection, depending on how the system is wired, the door will also close if one or both of the smoke detectors is removed from its base, if there is an open or short circuit, if the mains fails, if the power supply’s on-board manual release button is pressed, or if an (optional) external manual release button is activated Although only one electromagnetic door retainer is supplied with the BF375PEK, additional magnets can be connected. In most instances however only two magnets will be required to handle one set/pair of fire doors.