Contribution
Damage Risk Criteria for Impulse Noise: How Robust Are They Against Measurement Specifications?
* Presenting author
Abstract:
Many personnel in industry, construction, or the military need to wear Hearing Protection Devices (HPD) for avoiding acoustic trauma caused by hazardous impulse noise. As HPD generally impair communication and situational awareness, the individually required noise attenuation must be well justified. For impulse noise, the Maximum Permissible Exposures (MPE) per day are obtained through Damage Risk Criteria (DRC) which may take into account extrema, zero-crossings, amplitude/energy statistics, or physical ear models. The applicable national and international standards differ in terms of measurement specifications and assessment methods. For examining these differences, we created an ecologically valid dataset of weapon noises with peak SPL between 135 and 182 dB, comprising different weapon configurations and environmental conditions. We evaluated the individual and combined effects of technical parameters such as acquisition rate, oversampling, band limitation, quantization, SNR, and microphone position on the MPE with common DRC. Purely statistics- or model-based DRC were barely influenced by the tested parameters. DRC relying on precise zero-crossings, however, were highly affected by any sort of signal degradation. The obtained minimum technical requirements of DRC have direct implications for upcoming revisions of measurement guidelines, for future DRC standards, and for the development of wearable weapon noise dosimeters.