ARL-TN-0894 - Energy Monotonicity and Positive Pressure Duration Dependence of Auditory Risk Unit Hazards | U.S. Army Research Laboratory

摘要

Guidance on noise limits for Army materiel (per MIL-STD-1474E) describes two methods of assessing auditory hazards from exposure to impulsive waveforms: the Auditory Assessment Algorithm for Humans (AHAAH) and the A-weighted energy (AwE) method. Each method makes somewhat different hazard predictions for long positive-pressure-duration waveforms (such as those produced by large artillery muzzle blasts) and shorter positive-pressure-duration waveforms (such as those produced by rifle muzzle blasts), but the differences are not sufficiently large enough to establish consensus validity for either method when applied to muzzle blasts. However, hazard predictions differ far more significantly for extremely short positive-pressure-duration waveforms (such as the ballistic cracks produced by the passage of supersonic bullets). We assess the predicted hearing hazard for a series of waveforms with the same peak pressure and different time-dependencies to illustrate how the two different hearing hazard predictions change with waveform time-dependence while maintaining a constant peak pressure. We compare results of the methods, showing a range of positive pressure durations where AHAAH indicates increasing hazards, while AwE indicates decreasing hazards. Hazard observations for waveforms with positive pressure durations in this range will help resolve uncertainty in the validity of these two hazard assessment methods.