EVALUATION OF ACOUSTIC COMFORT IN APARTMENT BUILDINGS

Abstract: This thesis concerns assessment of acoustic comfort in apartment buildings. A new approach is followed, beyond noise annoyance investigation, which was the typical path so far. The latter involved acoustic descriptors, which characterize the structural components, being associated to self-reported noise annoyance.A socio-acoustic survey was conducted in 34 Swedish and Danish structures including 101 building units. Using a questionnaire, various parameters relevant to acoustic comfort were explored such as the living conditions, residents’ emotional reactions to the sound environment, personal data and other non-acoustic parameters, as well as self-reported annoyance due to various noise sources. Building and acoustic data were also collected to test their effect on the responses.Firstly, a noise annoyance assessment took place. Dose-response relationships were established for the resident’s annoyance, dependent on acoustic descriptors, due to airborne or impact sound. The latter was the biggest disturbance, especially impact noise types (walking, thuds) from neighbors on the floor above. The number of flats in a building was found to be an additional predictor for annoyance, regarding airborne and impact sound annoyance. The same applies to the size of flats only for airborne sound annoyance. The effect of extended low frequencies in acoustic descriptors for annoyance prediction was found negligible. Furthermore, acoustic comfort was assessed using the circumplex model of affect, a psychological tool for emotional evaluation of subjects. Two underlying dimensions for comfort were identified: pleasantness and activation. The impact sound descriptor predicted best pleasantness while the number of flats per building predicted best activation. A novel indicator was developed based on the pleasantness model, suggesting a measure for acoustic comfort entitled . Finally, based on the new indicator, 4 classes of acoustic comfort were proposed as “Very good”, “Good”, “Acceptable” and “No acoustic comfort”, which are entitled AC-1, AC-2, AC-3 and AC-4 respectively.Summing up, a new approach with novel results are presented in this thesis for assessment of acoustic comfort in apartments. A simple new comfort descriptor and a relevant classification system comfort are suggested as a tool for engineers, acousticians, designers and apartment occupants.