MEASUREMENT UNCERTAINTY IN THE FIELD OF ENVIRONMENTAL NOISE AND BUILDING ACOUSTIC MEASUREMENTS: EXPERIENCE FROM INTERLABORATORY COMPARISONS

In this paper the problem of measurement uncertainty in acoustic measurements has been discussed regarding the results of interlaboratory comparison (ILC). The measurement results of ILC in the field of environmental noise and in the field of sound insulation measurements (airborne and impact) have been examined regarding the proposed methods for calculation standard deviations in repeatability and reproducibility conditions. In the field of environmental noise measurements, of point sound source, the measurement results (19 laboratories) precision and accuracy are discussed regarding the microphone positions (on the reflection plane and close to the reflection plane). The results for expanded measurement uncertainty calculations, obtained following instructions from old ISO 1996-2:2007 and new ISO 1996-2017 are compared and discussed. In the field of building acoustic measurements the measured parameters of airborne and impact sound insulation (31 laboratories, 5 independent measurements) are compared regarding the obtained mean values and measurement uncertainties by removing outliers and finding standarddeviations in repeatability and reproducibility conditions according to ISO 5725-2 and ISO 12999-1:2014 and by approach described in GUM adopted for input parameters in each individual measurement and calculating overall standard uncertainty. In addition, the possibility to measure airborne sound insulation parameters by using acoustic camera has been considered regarding averaging the large number of measurement microphone positions in source and receiving room and finding measurement uncertainties for sound pressure levels and reverberation times in large number of measurement positions.