Inter-comparison of laboratory measurements of dynamic stiffness

The AIA (Italian Acoustic Association) carried out an Inter-Laboratory Test (ILT) to evaluate the repeatability and the reproducibility of dynamic stiffness measurements of materials used under floating floors in dwellings, according to the ISO 9052-1 standard. The main target of the ILT was to quantify the measurement uncertainty among different laboratories due to the flexibility in the test procedures described in the standard. The obtained results, show that different factors, such as: the measurement set-up, the application of a thin paste on the test specimen, the pre-load time, the determination of the resonant frequency dependence by the excitation force amplitude and the enclosed gas dynamic stiffness definition may affect the results of the measurement to varying degrees, depending on the material typology. Considerations on measurement procedures and proposals for an integration of the standard are reported.