Measuring and Protecting Against Impulse Noise The Derek Dunn Invited Noise Lecture on May 21 at AIHce EXP 2018 focused on the hazard of impulse noise. May 21, 2018 PHILADELPHIA — The Derek Dunn Invited Noise Lecture on May 21 at the 2018 American Industrial Hygiene Conference & Expo was a highlight of the day, focusing on the problem of impulse noise. Presenter Elliott Berger, division scientist with the 3M Personal Safety Division, discussed the definition and sources of impulse noise, measuring it, and PPE to protect workers against it. Fireworks and gunfire, as well as military munitions, are sources of impulse noise that ranges from 140 to 175 dBA, he explained, adding that it can be defined as a short burst of noise with rapid onset to a peak, followed by decay, that is created by the explosion of a gas. Sound level meters really aren’t useful for measuring impulse noise – they underestimate it by about 5 to 15 dB and may underestimate the auditory hazard at peaks at or above 150 dBA, he said. Accurate measurement requires proper mics, preamps, digital signal analysis, and recording apparatus, he explained. Berger, who is well known in the hearing protection community, stressed that a single shot from some types of rifles can measure 163 dBA, which is equivalent to eight hours of exposure at 85 dBA.