Measuring and identifying background noises in offices during work hours

In offices and working places, noise analysis aims at enhancing the acoustic comfort, the concentration and the oral communication quality. According to the current regulations, background noise is evaluated in unoccupied conditions, but it is interesting to know its dynamic behaviour in occupied state. The knowledge of the noise components may be useful for improving the estimation of comfort parameters, such as the distraction distance (ISO 3382-3) or Speech Transmission Index (IEC 60268-16). The present study suggests a method to extract background noises values with statistical techniques from recordings made during work hours with sound level meters. Statistical techniques were used for the analysis of short-Time sound pressure levels obtained over long-Term recordings: Gaussian Mixture and Percentile Levels. Noise sources are identified from octave bands analyses. Measurements done using Gaussian Mixture were compared with the ones done with Percentile Levels. Results show some differences between the two techniques.