Uncertainties and validation procedures for the Compact Measurement Setup

By using a small floor mock-up, the impact sound reduction of floor coverings can be determined by measuring the difference of the acceleration levels instead of measuring a sound pressure level in a receiving room (ISO 10140). The setup is validated for locally reacting floor coverings and standardized within the ISO 16251-1. To decide whether the covering under test can be considered as locally reacting, a validation procedure was developed on the basis of the standard uncertainties of the differences for every measurement position. A further issue for the method is that the measurement equipment must be capable of handling the signals. To check this, the bare floor acceleration levels of existing compact setups are proposed to be used as a criterion. Both validation methods are compared to actual measurements. Furthermore, the uncertainties of a measurement at a compact setup are considered due to the method of the GUM. This estimate of the uncertainty is compared to uncertainties according to ISO 12999-1. Finally, standard deviations of measurement results obtained at different compact setups and results obtained with different tapping machines at the same compact setup are presented which give an overview of the different uncertainty contributions.