Effects of Ventilation Noise Due to Frequency Characteristic and Sound Level

Abstract

In two studies twelve subjects were exposed to different types of ventilation noise in a simulated office. In Study 1, a ventilation noise with a gradually falling frequency/level spectral character, was considered as more annoying than a ventilation noise with a band of raised levels around 43 Hz and in particular a tone at 43 Hz. The differences in acceptable comfort levels were aproximately 7 dB when comparing the tonal and gradually falling frequency/level ventilation noise. The frequency character thus has to be considered when evaluating the annoyance due to ventilation noise. The result from Study 2 gives support to the suggested lowering of the highest acceptable level of ventilation noise from 40 to 35 dB(A) and that the level should be reduced even more in environments designed for intellectual work.