Abstract: Actuation circuitry causes emergency energization of a vehicle fire and explosion detection and suppression system when the vehicle is not in operation. The actuation circuitry includes a simple fire and/or explosion detector which draws a small amount of power relative to that required by the main fire and explosion detection and suppression system when operative. When the detector detects an event which may be a fire or explosion the actuation circuitry activates the main system which analyzes the event by its more sophisticated circuitry and acts accordingly. When such event is no longer detected by the detector of the actuation circuitry, the main system is shut down.

Abstract: Self-calibrating radiation detection apparatus comprising a detector element and calibration apparatus for maintaining a generally constant response of the detector element to a predetermined radiation input notwithstanding changes in the level of background radiation sensed by the detector element. There is also provided control apparatus for operating a plurality of radiation detectors including apparatus for disabling the output of the detectors in response to a continuing radiation input of predetermined duration.

Abstract: Discrimination apparatus for use in a fire and explosion detection and suppression system which includes plural detectors and suppression apparatus operated thereby and including apparatus for sensing detection by a first number of detectors within a predetermined time period and providing an output signal only when the first plurality of detectors detect within the predetermined time period and apparatus operative in response to the output signal for inhibiting operation of the suppression apparatus.

Abstract: A hand-held collet for holding a tool or the like within displaceable jaw pieces which are mounted on sprung rods accommodated within a hollow tubular handle.