22.07.2011
Uncertainties are currently not taken into consideration with the required degree of transparency in most applications in building acoustics. To initiate progress in this matter, a project has been allocated to the PTB working group "Building Acoustics" by the Deutsches Institut für Bautechnik, the highest building authority in Germany.
The investigations are carried out in the example of airborne sound insulation. Starting point was a compilation of the relevant quantities which enabled a detailed uncertainty analysis. The magnitude of the 16 uncertainty components was determined in part analytically but mostly on the basis of existing measurement results. Data used originated from comparison measurements regularly taking place at PTB and at MPA Dortmund, from a round robin test with a heavy lime brick wall organized by PTB (Figure 1) and from several other PTB-internal and external sources. Some of the uncertainty contributions appear only in combination in the data, and therefore their contributions could be determined only in summary.
It was then possible to derive quantitative criteria for several typical problems in building acoustics from the uncertainties. Thus a detailed proposal was worked out for the approval of a new laboratory or rather a newly built test suite.
Figure 1. Sound insulation R of a nominally identical lime brick wall measured in 20 different test suites as a function of frequency f
Contact person:
V. Wittstock, FB 1.7, AG 1.71 Email: volker.wittstock@ptb.de