HAZARD DETECTION

摘要

In order to allow a smoke detector unit (1) to be utilised in, for example, a domestic kitchen environment, appliances (11, 21) whose operation is commonly associated with the generation of non-hazardous smoke or aerosols are connected to a conventional mains supply socket (7, 19) via a current monitoring unit (3, 15). The current monitoring units include a radio transceiver (13, 23) which transmits the operational status of the appliances (11, 21) to a corresponding transceiver (25) of the smoke detector unit 1. If the signals transmitted by the current monitoring units indicate that the appliances (11) and (21) are off, the smoke detector unit (1) generates a warning signal when the smoke density exceeds a lower threshold. If one of the appliances (11) and (21) is detected to be on, the smoke detector unit generates a warning signal only when a second, higher threshold of smoke density is exceeded. Optionally, when the higher smoke density threshold is exceeded, the smoke detector unit transmits the signal to the current monitoring unit to power off the appliances. The invention is also applicable to the detection of other characteristics of ambient fluid, such as temperature or the presence of a particular gas or vapour.