Noise measurement method for luminaires with tubular fluorescent lamps

The aim of this project has been to propose a method to determine sound power level produced by luminaires with tubular fluorescent lamps. Because fluorescent lamps are very low-level noise sources the requirements for the measurement method concerning the measuring site, equipment and carrying out the measurements have to be defined more explicitly than has been done in present sound power level measuring methods. A new method complying with the above requirements is proposed. It is based on ISO 3741 and ISO 3742. In addition a simplified method for measuring only A-weighted sound power level is presented. The method has been tested by having four different laboratories carrying out measurements on two different luminaires with tubular fluorescent lamps. The results indicate that it is possible to make reliable and repeatable measurements using the proposed method if the background noise level can be kept low enough, and if the mounting conditions and the way of determining the sound power level are the same. In addition to the Round Robin measurements some preliminary measurements are accounted for. They include measurements to investigate how the mounting of the luminaire during the measurement affects its sound power level. It was also investigated if a simplified method could be used if only A-weighted sound power level is of interest.