Optical smoke detectors have always been recognised as good detectors for general use. They are regarded as particularly suitable for smouldering fires and escape routes. The performance of Orbis Marine optical detectors is good in black as well as in white smoke. In this respect Orbis detectors are different from traditional optical smoke detectors which perform far better in white smoke than in black. Orbis I.S. Optical Smoke Detectors are also designed to reduce significantly the incidence of false alarms through over-sensitivity to transient phenomena. Orbis I.S. Optical Smoke Detectors are recommended for use as general purpose smoke detectors for early warning of fires in most areas