engleski

Interlaboratory comparison of sound insulation measurements in building acoustics

An interlaboratory comparison was organized in 2011 among 14 Croatian laboratories with the aim of proficiency testing in the field of sound insulation measurements. The airborne and impact sound insulation of a floor have been measured and the results are expressed as sound reduction index (R') and normalized impact sound pressure levels (L'n) in one-third octave frequency bands from 100 Hz to 3150 Hz. The weighted sound reduction index (R’w) and weighted normalized impact sound pressure level (L'nw) are also compared. The laboratories had to follow procedures described in the standards for the airborne sound insulation (HRN EN ISO 140-4, HRN EN ISO 717-1) and for the impact sound insulation (HRN EN ISO 140-7, HRN EN ISO 717-2) measurements. The laboratories had to carry out five repeated independent measurements under repeatability conditions according to EN 20140-2. The results have been compared according to ISO 5725 where outliers are detected. Large standard deviations in some frequency bands have been eliminated by using Cochran’s statistics which compares standard deviations of each laboratory with the mean standard deviations of all laboratories. Outliers in mean value results have been eliminated by using Grubb’s test. The repeatability and reproducibility for airborne sound reduction index were comparable with those given in EN 20140-2 for laboratory conditions. Impact sound insulation repeatability values are comparable with those given in EN 20140-2 in all frequency bands, but reproducibility values for normalized sound pressure levels at higher frequencies were worse than those given in EN 20140-2.

interlaboratory comparison; proficiency testing; airborne and impact sound insulation; sound reduction index; normalized impact sound insulation; measurement uncertainty; repeatability; reproducibility

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