Laboratory Floor Impact Testing

Building Acoustics

Laboratory Floor Impact Testing

SINUS Comet Test Bench Accelerometer Method

The COMET Impact sound measuring test bench is a compact and controlled method for testing impact sound isolation, for comparing the sound impact performance of floor products under the same test conditions and for determining the improvement in impact sound isolation from changes to product material or construction specifications.

The COMET impact sound measuring test bench is designed to provide a compact method to determine the sound impact isolation levels in accordance with the requirements of DIN EN ISO 16251-1.

Previously testing of sound impact isolation required a laboratory which included two rooms, one above the other, with a size of 50 m³ each, or alternatively testing was conducted in-situ in buildings to demonstrate the relative performance of product A compared to product B so that a selection could be made by the architect or owner.

Traditional laboratory testing of sound impact isolation using two rooms was expensive.

Although manufacturers are interested in developing new floor products with satisfactory or improved sound isolation characteristics, the traditional laboratory testing can be very expensive.

To assist small and medium sized manufacturers the German PTB and the Forschungsinstitut für Leder und Kunststoffbahnen (FILK – German Research Institute for Leather and Plastic Sheeting) have developed a new compact method for testing sound impact isolation using a test bench that replaces the two-room laboratory test.

The COMET Method utilizes multi-channel data acquisition using accelerometers an. This method replaces the two-room facility with a measuring station that has the size of a desk. As a result of the project the COMET sound insulation measuring station was created leveraging our measurement equipment in combination with a software specifically designed by us.

The COMET test bench consists of a 1.2m x 0.8m x 0.2m concrete slab which rests in a vibration-damped Euro-format steel rack. A standard sound insulation tapping machine is used for impact sound excitation. Two measurements are performed, one with and one without floor covering on the concrete slab.

The acceleration or velocity levels underneath the concrete slab are measured and the difference between the average accelerations or velocities is evaluated in accordance with the methods of DIN EN ISO 717-2. The results of both methods show only very slight deviations with respect to floor coverings with local elastic deformation, such as PVC, carpet or linoleum. Laminate flooring exhibits larger deviations, since it does not deform locally.

The observed deviations are relatively minor, however, compared to the uncertainties in building acoustics.

For further information please refer to the document PTB_COMET.pdf and the website of the federal test institute Physikalisch-Technische Bundesanstalt (PTB).

Tapping machines:

SINUS TM50 Tapping Machine

CESVA M1006 Tapping Machine


DIN EN ISO 717-2: Rating of sound insulation in buildings and of building elements – Part 2: Impact sound insulation

DIN EN ISO 16251-1: Laboratory measurement of the reduction of transmitted impact noise by floor coverings on a small floor mock-up

Technical specifications

Design of the measuring station

Included analyzer: Soundbook_MK2 (see also Soundbook_MK2 for further details)


Standard concrete floor model (developed by the PTB)




SINUS COMET software


6 x accelerometers


Standard sound insulation tapping machine

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