Semiconductor Based Line Type Heat Detector Following European EN54-22 Standard

Abstract

Line type heat detectors (LTHD) are important for temperature based fire detection in applications with a large number of detection points. Preferably they are used in aggressive environments showing extreme temperatures, high humidity, dust exposure, aggressive gases, or others. Typical applications are in traffic tunnels, cable channels, or conveyor belts. Europe is actually preparing the new EN54-22 standard for resettable line type heat detectors (LTHD). This new standard includes a classification of the various types of detectors, reaction classes, and test procedures. It will allow more adequate testing compared to the actual procedure based on EN54-5 for point detectors. It will cover all types of resettable LTHD as semiconductor cables, fiber optic cables, pneumatic systems, and analog cables. The paper presents an overview on the actual draft of the standard. During the last years, Metaphysics has developed a new semiconductor sensor based LTHD. In contrary to other types of LTHD it is using discrete semiconductor temperature sensors such allowing an exact localization of the fire and highly flexible programming of the alarm functionality. Due to a special, patented high-speed bus system it has been shown in several public tests that this system is significantly faster than other LTHD systems. After first experience in the field, more features like loop setups with increased availability and network solutions have been added recently. The paper shows the physical principle of this approach and its system design completed by test reports and application examples.