Ultrasonic noise measured close to the ear
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A portable device can contribute to the more accurate determination of airborne ultrasound exposure
For years, airborne ultrasound (20 kHz to 100 kHz) has been suspected of causing negative health effects. However, it has not been possible to reliably measure ultrasound exposure at workplaces until now. Conventional hand-held sound level meters are not suitable for these often very complex, inhomogeneous and rapidly changing ultrasound fields. So far, sound exposimeters for personal measurements have covered the medium acoustic frequency range up to 8 kHz only.
For this reason, as part of a technology transfer project, PTB and the Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung (Institute for Occupational Safety and Health of the German Social Accident Insurance) have jointly developed a high-frequency personal ultrasound exposimeter. It is especially intended for personal measurements and can additionally be used like a hand-held sound level meter in the high-frequency audible range.
For personal measurements, the corresponding microphone, which can be positioned separately and is fairly small, is attached in close proximity to the respective person’s ear. Due to the short wavelengths of airborne ultrasound, the distance to the ear needs to be kept as short as possible to be able to realistically determine the sound pressure reaching the ear. The device itself can be attached to a belt, for example.
The new device was validated by means of comparison measurements with an ultrasound level measurement system tested up to 100 kHz. In a series of measurements in various simulated industrial work scenarios, the two devices delivered comparable results. The spatially resolved measurement data collected during these measurements of various ultrasound fields are also interesting for further applications and analyses and will therefore be published in a database.
Further practice tests are now being carried out with the current version of the device. At the same time, measurement and calibration procedures for routine applications are being developed. We are actively looking for a manufacturer to put this device, which is currently only an experimental model, into practice.
Contact
Michal Cieslak
Department 1.6
Sound
Phone: +49 531 592-1538
michal.cieslak(at)ptb.de
Scientific publication
M. Cieslak, C. Kling, A. Wolff: Development of a personal ultrasound exposimeter for occupational health monitoring. Int. J. Environ. Res. Public Health 18 (2021)