METHODS FOR ASSESSING THE MAINTAINED AND INITIAL DETECTION PERFORMANCE OF OCCUPANCY SENSORS

As installations of occupancy sensors become more common, concerns reg arding their performance characteristics arise. People claim that ''th e lights turn off while the room is occupied,'' that ''the lights turn on when the room is unoccupied,'' or that ''the lights do not turn on when the room is entered.'' These anecdotal stories indicate that pub lished coverage areas may be exaggerated and that initial detection ab ilities are questionable. Manufacturers often publish maximum coverage areas, but sometimes do not warn the specifier that coverage area wil l vary with the sensitivity setting and the type of motion performed i n the space. This paper discusses two methods that were used to evalua te the maintained and initial detection performance of architectural m otion sensors- Performance data are presented on iso-sensitivity conto ur plots, which graphically describe the ability to maintain detection for small hand movement in a space at maximum and minimum sensitivity settings. Data are also presented for initial detection performance c haracteristics, which describe the distance a person must travel into a room before motion is detected.