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Results of the National Institute for Occupational Safety and Health - U.S. Environmental Protection Agency interlaboratory comparison of American National Standards Institute S12.6-1997 methods A and B.

Murphy WJ; Byrne DC; Gauger D; Ahroon WA; Berger E; Gerges SNY; McKinley R; Witt B; Krieg EF

J Acoust Soc Am 2009 May; 125(5):3262-3277

https://doi.org/10.1121/1.3095803

20035378

The National Institute for Occupational Safety and Health and the Environmental Protection Agency sponsored the completion of an interlaboratory study to compare two fitting protocols specified by ANSI S12.6-1997 (R2002) [(2002). American National Standard Methods for the Measuring Real-Ear Attenuation of Hearing Protectors, American National Standards Institute, New York]. Six hearing protection devices (two earmuffs, foam, premolded, custom-molded earplugs, and canal-caps) were tested in six laboratories using the experimenter-supervised, Method A, and (naïve) subject-fit, Method B, protocols with 24 subjects per laboratory. Within-subject, between-subject, and between-laboratory standard deviations were determined for individual frequencies and A-weighted attenuations. The differences for the within-subject standard deviations were not statistically significant between Methods A and B. Using between-subject standard deviations from Method A, 3-12 subjects would be required to identify 6-dB differences between attenuation distributions. Whereas using between-subject standard deviations from Method B, 5-19 subjects would be required to identify 6-dB differences in attenuation distributions of a product tested within the same laboratory. However, the between-laboratory standard deviations for Method B were -0.1 to 3.0 dB less than the Method A results. These differences resulted in considerably more subjects being required to identify statistically significant differences between laboratories for Method A (12-132 subjects) than for Method B (9-28 subjects).

Hearing-conservation; Hearing-impairment; Hearing-disorders; Hearing-loss; Hearing-protection; Personal-protective-equipment; Personal-protection; Standards; Noise-induced-hearing-loss; Noise-protection; Author Keywords: ANSI standards; ear protection; hearing; noise (working environment); noise pollution; occupational health; occupational safety; safety devices

William J. Murphy, Hearing Loss Prevention Team, National Institute for Occupational Safety and Health, 4676 Columbia Parkway, MS C-27, Cincinnati, Ohio 45226-1998

JASMAN

20090501

Journal Article

wmurphy@cdc.gov

2009

5

0001-4966

DART

Journal of the Acoustical Society of America

OH; MA; AL; IN; CA