Hazardous Exposure to Intermittent and Steady-State Noise

Abstract

The following document was prepared by NAS-NRC CHABA Working Group 46. This group was asked to specify damage-risk criteria for exposure to sound. The paper contains graphs of maximum sound-pressure levels and durations of exposures that the Working Group believes would be tolerable and examples of the use of these graphs in addition to background information and a discussion of the rationale, assumptions, limitations, and general problems pertinent to the development and application of a damage-risk criterion and related exposure contours.

Damage Risk from Impulse Noise. (les Risques auditifs et extra auditifs des bruits impulsionnels)

“…Although there are some methodological questions, this method shows a surprisingly good correlation between TTS and PTS. Kryter et al [24] postulated that the TTS observed after one working day should approximate the amount of PTS after ten years work in the same environment. However, these data are mean data for groups and are not applicable to the prediction of individual susceptibility.…”

“…For this purpose, a work station is used for [1][2][3][4][5][6][7][8][9][10] which the Franco-German Research Institute, Saint-Louis, France (ISL) has developed the software 24 .…”

Auditory Fatigue Following Tone-Burst Trains at 2.2 Kc

“…We have correlated the seven Kryter one at a time with the Nox, and the 4 Kc TTS . 5 -e mm also with the Nox. The results are in Table V.…”

“…Following in general a proposal of Working Group No. 46 of the NAS-DRCArmed Forces Committee on Hearing, Bioacoustics and Biomechanics (Kryter, et al, 1966), an audiometric loss approaching social significance is one of 10 dB hearing level (HL) at 1 kc, 15 at 2 kc, or 20 at 3 kc and higher. This loss, expressed as an area on an audiogram chart, we call a Kryt, from the original Greek Kriterion; plural Kryter.…”

Combined effects of noise and ototoxic drugs.

“…3 (13)(14)(15)(16). At slightly higher levels, a small but definite percentage of the people thus exposed will become hearing-impaired, and that percentage will increase with increased exposure intensity.…”