Micro-perforated foil absorbers

© Kaefer
Nachhallzeiten vor und nach dem Einbau der Schallabsorber im Freizeitbereich.

With its sport and recreational ares the total volume of leisure center DIE WELLE in Gütersloh (Germany) amounts to about 10.000 m3. All ceilings are of convex shape. Decorative wooden boardings and girders are used for the roof construction with glass domes and windows on top. Plaster, tiles and coated concrete form the walls. The sport and recreational area is separated by a glass wall. Sophisticated architectural demands in DIE WELLE led to first-time application of a novel transparent foil absorber. The required sound absorption maximum of the absorbers had to be between 500 and 2000 Hz. Result of the development wa a two-layer MICROSORBER® with sound absorption coefficient according to DIN EN 20354.


Installation and performance

The two-layerred foil absorbers have been mounted in front of the convexly shaped ceilings in the recreational and sport area. The first foil was fixed with a wooden construction at 100 mm distance and the second 30 mm in front of the first. Over all thickness of the absorber came to 130 mm. The absorber foils consist of polycarbon material, are transparent, non-abvasive, UV-stabilised, chemically resistant, antistatic and comply with fire-related requirements (meets german Baustoffklasse B1). Now even larger glass facades can be acoustically treated without abandoning optical transparency.

To evaluate the effectiveness of the acoustic treatment measurements of sound pressure level and reverberation time have been carried out before and after the reconstruction of recreational and sport areas. The sound pressure level was lowered by 5.2 dB in the recreational area and by 3.8 dB in the sport area. The full reconstruction was carried out during a period of 28 days.

The noise level and reverberation time at leisure center DIE WELLE have thoroughly been decreased by fitting foil absorbers. Suvjective judgements by visitors and staff are very positive. Visiting the center has become much more pleasant and restful by the reduction of sound pressure level and reverberation time. The architectural impression has only slightly been altered due to use of transparent absorbers. As a result of these room acoustical improvements even musical events can take place at the center.


Überzeugende Lärmminderung im Freizeitbad DIE WELLE, Gütersloh. Archiv des Badewesens 51 (1998), H. 7. (Short report in: IBP-Mitteilung 25 (1998), Nr. 329

Our industrial partner:
KAEFER Isoliertechnik, Bremen - http://de.kaefer.com