An increasing number of workplaces uses ultrasonic techniques in many different fields of industry. Widespread applications are welding, cleaning and cutting. Frequently, airborne ultrasound is emitted as a side effect at machines using ultrasonic technology. Employees working at or in the vicinity of these workplaces are being exposed to the airborne ultrasound field. As the exposure to airborne ultrasound poses a potential health hazard, the quantitative determination and the assessment of this exposure to ultrasound is essential. Since measurement procedures established in the audible frequency range are not sufficiently capable to quantify the exposure of airborne ultrasound, a new measurement procedure adapted to the specifics of ultrasound was needed. Within the scope of Ears II, a European research project, the Physikalisch-Technische Bundesanstalt (PTB) together with the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA of DGUV), has developed a measurement procedure for the determination of the occupational exposure to airborne ultrasound. The development of the measurement procedure was based on the detailed characterization of the ultrasound field of a representative industrial sound source in the laboratories of PTB and IFA. Those investigations revealed the large nearfield and the pronounced speckle-like structure of the sound field. The drafted measurement procedure is capable to cope with those and further challenges arising when measuring airborne ultrasound. In addition, the measurement procedure was applied to different ultrasonic modalities during field tests in industry to verify the practicability for investigations in occupational safety and health. Finally, the results led to a procedure which enables the determination of the occupational exposure to ultrasonic noise with a minimized expenditure of time and effort. Here, we present the novel measurement procedure and the results of the field tests.
