Description

ASA S3.44 Part 1 – American National Standard – Acoustics – Estimation of Noise-induced Hearing Loss – Part 1: Method for Calculating Expected Noise-induced Permanent Threshold Shift (a modified nationally adopted international standard)

ANSI/ASA S3.44-2016/Part 1/ISO 1999:2013 (MOD) specifies a method for calculating the expected noiseinducedpermanent threshold shift in the hearing threshold levels of adult populations due to various levelsand durations of noise exposure; it provides the basis for calculating hearing disability according to variousformulae when the hearing threshold levels at commonly measured audiometric frequencies, or combinationsof such frequencies, exceed a certain value. This modified standard allows an equivalent effective level (EEL),with a different exchange rate, to be substituted for L_EX,8h.

The measure of exposure to noise for a population at risk is the noise exposure level normalized to a nominal8 h working day, L_EX,8h, for a given number of years of exposure. ANSI/ASA S3.44-2016/Part 1/ISO 1999:2013(MOD) applies to noise at frequencies less than approximately 10 kHz which is steady, intermittent, fluctuating,or irregular. Use of ANSI/ASA S3.44-2016/ISO 1999:2013 (MOD) for sound pressures exceeding 200 Pa (140dB relative to 20 µPa) is recognized as extrapolation.