Uncertainty investigation of field measurements of airborne sound insulation

Abstract

Sound insulation is very important for the acoustic quality of buildings. The Brazilian Association of Technical Standards, ABNT, published a set of standards concerning the evaluation of the performance of buildings up to five floors, ABNT NBR 15755, and sound insulation is one the considered topics. Minimum, intermediate and superior values are presented for some acoustic parameters. In order to make measurements carried out by different professionals comparable with the values established in the standards, the uncertainty of the results shall be expressed. The Guide to the Expression of Uncertainty in Measurement, ISO/IEC Guide 98 (GUM), is the international document that standardizes how to assess the uncertainty of a measurement result. In general, two types of methods are used to measure sound insulation parameters: the classical method and the new method or impulsive response method. However, there is not an established and simple procedure to obtain the measurement uncertainty. Uncertainties estimates are available only for the classical method. Measurements of airborne sound insulation between rooms were carried out in field conditions with the impulse response method and the work presents a study of the estimate of the uncertainties of the results, in accordance with the GUM.