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A compact measurement setup for the determination of the impact sound reduction of floor coverings

24.06.2014

Impact sound reduction is the main acoustical parameter for floor coverings. According to ISO 10140 it is determined by using a special test facility consisting of two vertically aligned rooms with a minimum volume of 50 m³ each. Building and keeping such a test facility available is unprofitable for smaller enterprises, because of the specific requirements which have to be fulfilled. The compact setup, which was developed at PTB, reduces the cost and the time needed for such a measurement.

During two AiF (Arbeitsgemeinschaft industrieller Forschungsvereinigungen) funded research projects a compact measurement setup for the determination of the impact sound reduction was developed on the basis of a 1.2 m × 0.8 m × 0.2 m concrete slab. Instead of a measurement of the sound pressure level in a receiving room according to DIN EN ISO 10140, the difference of the acceleration levels at the bottom of the concrete slab with and without the specimen is measured.

Many measurements were made using soft- and plate-like coverings in the test facility according to DIN EN ISO 10140 and at the compact measurement setup. The results of the measurements are depicted in figure 1. Considering the critical difference, which is an indicator of the uncertainty of such a measurement, the agreement for both methods and soft floor coverings (PVC, carpets, linoleum) is very good.

Figure 1: Weighted impact sound reduction ΔLw for 122 floor coverings determined at the compact measurement setup according to ISO 16251-1 (vertical axis) and in the test facility according to DIN EN ISO 10140 (horizontal axis).

The differences between both methods at laminates are not caused by the compact setup. The differences are the result of bad coupling between the covering and the floor. Due to the additional air gaps between the floor and the covering it is possible to measure higher impact sound reductions in the test facility according to DIN EN ISO 10140. The differences for heavy floor coverings like screed are the consequence of a variation of the vibrational behaviour due to the floor covering. Therefore, no valid results for measurements at the compact setup for heavy floor coverings can be expected. A validation procedure was developed at PTB to identify such invalid measurements.

On the basis of the research at PTB an international standardized method for the determination of the impact sound reduction at compact measurement setups was developed (ISO 16251-1: Laboratory measurement of the reduction of transmitted impact noise by floor coverings on a small floor mock-up - Part 1: Heavyweight compact floor). In cooperation with PTB the company SINUS Messtechnik GmbH sells this measurement setup including all the necessary measurement technology. The main aim of the project to reduce the effort needed for such a measurement has been fully reached.

References:

[1] Schmidt, J.H.; Wittstock V.; Foret, R.; Fichtel, F., Scheck, J.: Measuring the impact sound reduction at a compact measurement setup – design, results and uncertainties. Building Acoustics, Volume 20, Number 2, Pages 107 – 140, 2013

Contact person:

Jan-Henning Schmidt, Dept 1.7, WG 1.72, e-mail: jan-henning.schmidt@ptb.de