601P detectors are capable of detecting the visible smoke produced by materials which smoulder or burn slowly, i.e. soft furnishings, plastic foam etc; or "smoke" produced by overheated but unburnt PVC. These detectors are particularly suitable for general applications and areas where cable overheating may occur, e.g. electrical services areas.
Optical only detectors are not suitable for detecting fast burning fires producing little visible smoke or very black smoke.
The novel design of the asymmetrical sampling chamber and signal processing techniques stop unwanted alarms caused by very small insects, i.e. thrips. Smoke entering the sampling chamber scatters the infra-red light pulses onto a photodiode.
These pulses are converted to an electrical signal which is compared against a preset alarm level or transmitted as an analogue value.