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Develop Hearing Protection Laboratory and Fit-Testing Methods-FY07

NOTE: This page is archived for historical purposes and is no longer being maintained or updated.


  • Develop new laboratory testing facilities suitable for both ANSI and ISO testing of real-ear attenuation.
  • Develop methods to estimate the noise attenuation from HPDs in the workplace and validate the new laboratory subject-fit protocol with onsite field-testing methods.
Lab test equipment

Applicable Standards

  • ANSI S12.6-1997

Key Partners

  • PRL
  • Howard Light Industries


  • U.S. Army Aeromedical Research Laboratory
  • Gentex Corporation

Project Scope

  • The new laboratory incorporated multiple methods for measuring hearing threshold to permit comparisons of their efficacy. The HLR program studied the performance of proposed fit-testing systems and demonstrated the equivalence of attenuation estimates between ANSI S12.6-1997 Method B and a computer-based fit-test system. The HLR program developed methods to estimate protected exposure levels from limited data and to predict the quality of a user's fit based upon statistical classification techniques.


  • None


  • Murphy WJ, Franks JR, Berger EH, Behar A, Casali JG, Dixon-Ernst C, Krieg EF, Mozo BT, Royster JD, Royster LH, Simon SD, Stephenson C [2004]. Development of a new standard laboratory protocol for estimation of the field attenuation of hearing protection devices: sample size necessary to provide acceptable reproducibility. J Acoust Soc Am 115(1): 311-323.
  • Franks JR, Murphy WJ, Harris D, Johnson JL, Shaw PB [2003]. Alternative field methods for measuring hearing protector performance. Am Ind Hyg Assoc J 64(4):501-509.
  • Berger EH, Franks JR, Behar A, Casali JG, Dixon-Ernst C, Kieper RW, Merry CJ, Mozo BT, Nixon CW, Ohlin D, Royster JD, Royster LH [1998]. Development of a new standard and laboratory protocol for estimating the field attenuation of hearing protection devices, Part III: the validity of using subject-fit data. J Acoust Soc Am 103: 665-672.


  • None
Page last modified: July 20, 2007
Page last reviewed: July 20, 2007 (archived document)
Content Source: National Institute for Occupational Safety and Health (NIOSH)