Publication Date


Document Type


Degree Name

M.A. (Master of Arts)

Legacy Department

Department of Communicative Disorders


Noise--Measurement; Audiometry


Ambient noise levels were measured within 13 audiometric test booths contained in 12 different industrial mobile test vans and trailers operating in the Midwest. These levels were recorded manually in octave bands and tape recorded for third octave spectral analysis at a later time. The resulting levels were compared with the 1983 Occupational Safety and Health Administration (OSHA) Maximum Permissible Ambient Noise Levels (MPANLs) and the MPANLs in American National Standards Institute (ANSI) S3.1-1991 to determine if each booth was in compliance with these standards. The results indicated that all 13 (100%) of the industrial mobile test vans and trailers evaluated in the study complied with 1983 OSHA permissible levels. With regard to the 1991 ANSI MPANLs, 5 (38%) of the 13 booths were in compliance at all frequencies. Those that failed did so at 125, 250, and 500 Hz. The data were evaluated in regard to the MPANLs suggested by the National Hearing Conservation Association in 1996. It was determined that all 13 (100%) booths were in compliance with the new NHCA criteria. Since 1983 OSHA and 1996 NHCA MPANLs do not extend below 500 Hz, MPANLs were proposed for 250 and 125 Hz based on the concept of the upward spread of masking. The data were evaluated in regard to the proposed MPANLs, and all 13 (100%) of the booths were in compliance. The ambient levels outside the mobile units were also gathered for informational purposes.


Includes bibliographical references (pages [38]-40)


xi, 111 pages




Northern Illinois University

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