Self-testing fire door

A self-testing fire door system comprising:

• a door frame;
• a fire door attached to the door frame via one or more hinges, wherein the fire door is moveable between a closed position, in which the fire door covers an opening in the door frame, and an open position, in which the opening in the door frame is uncovered;
• a first distance sensor arranged to measure a first distance between a top portion of a non-hinged side of the fire door and the door frame, wherein the first distance sensor comprises a first sensor member arranged on the door frame and a second sensor member arranged on the fire door adjacent to the first sensor member when the fire door is in the closed position, wherein the first distance sensor and the second distance sensor are in communication via a hardwired connection, and wherein the first distance sensor comprises an analogue to digital converter;
• and
• a processor configured to:
• measure, via the first distance sensor, the first distance;
• and
• output the first distance;
• wherein the first distance sensor comprises three Hall effect sensors arranged such that each Hall effect sensor is aligned along different axes to each of the other Hall effect sensors in a triaxial arrangement,
• wherein the system further comprises a second distance sensor arranged to measure a second distance between a bottom portion of the non-hinged side of the fire door and the door frame, wherein the second distance sensor comprises a first sensor member arranged on the door frame and a second sensor member arranged on the fire door adjacent to the first sensor member when the fire door is in the closed position,
• wherein the first distance is a first distance between a first surface at the top portion of the fire door and a portion of the frame, and the second distance is a second distance between the first surface at the bottom portion of the fire door and the portion of the frame, and
• wherein the processor is further configured to detect a warp or twist in the door or frame based on the measured first and second distances.