Assessment of Noise-induced Annoyance by Tones in Noise from Building Mechanical Systems

Prominent tones in noise generated by mechanical equipment in buildings can cause complaints from occupants in buildings. The ISO 1996-2 and ANSI S1.13 standards describe methodologies and metrics to quantify tonality perception, but the influence of tones in noise on human annoyance and performance is not fully understood yet. This paper investigates annoyance responses of humans while exposed to background noise with tonal components. Twenty participants completed digit span tasks while exposed to noise signals with differing levels of tones and overall loudness. Subjects were also asked to rate their annoyance after completing tasks under each noise signal. The subjective testing was carried out in the indoor acoustic testing chamber at the University of Nebraska. A dose-response model is investigated to predict the upper limits of acceptability for tonalness using assorted noise metrics.