Sound quality in offices - quietness versus privacy

In Germany, the noise in offices in which mentally demanding tasks are performed, must not exceed an A-weighted energyequivalent level of 55 dB(A). In the framework of a larger study, the noise climate in a number of open plan offices has been investigated. It was found that open plan offices which are rated “quiet” show on the average a percentile loudness of N5 = 5soneGD corresponding to pink noise of about 44 dB(A). In “loud” offices, the loudness is at least a factor of two larger and workers can be annoyed by the background noise, reducing their performance. On the other hand, in “quiet” offices the content of telephone calls of colleagues can be easily understood, reducing the privacy. Results of speech intelligibility tests suggest that optimum privacy is obtained only at unacceptably loud background noises.