HLR Program Facilities

Research facilities include specialized laboratories, a mobile audiometric research facility, and instrumentation and equipment to provide comprehensive field study capabilities.  The laboratories include:

• The acoustic test chamber (located in Pittsburgh), which is a 1300 m3 reverberation chamber spacious enough to accommodate large machinery. The chamber is equipped with a Bruel & Kjaer Pulse Sound Power System and precision-grade sound measuring instruments capable of < 1dB discrimination of sound power level. This chamber is used for precision measurement of total sound emissions from large equipment. It was accredited in 2005 by the National Voluntary Laboratory Accreditation Program (NVLAP) for sound power measurements.
  
  
• Two hearing protector laboratories (one in Cincinnati, one in Pittsburgh) that were fully remodeled in 2003. They include a reverberation room and use the same computers and software to run standard hearing protector tests. The lab in Pittsburgh is accredited by NVLAP for the measurement of real ear attenuation of hearing protection devices in accordance with test standard ANSI 12.6-1997 R2002.
  
  
• Two clinical audiometric suites (one in Cincinnati and one in Pittsburgh). The labs contain clinical audiometers (which include high-frequency test capability), tympanometers, otoacoustic emission measurement systems, and a hearing aid analyzer. The Cincinnati facility also includes a small audiometric test room similar to those commonly found in occupational settings; this is used to evaluate the feasibility of test strategies in an occupational versus clinical environment. An additional small-animal noise-exposure and test facility has been installed at the University of Cincinnati Biological Sciences Department. These facilities are capable of conducting auditory evoked potential and otoacoustic emission testing.
  
  
• Two anechoic chambers (one in Cincinnati, and a larger chamber in Pittsburgh) and a hemi-anechoic room in Pittsburgh sufficiently large to drive construction equipment into it. The PRL hemi-anechoic room is new and is nearly complete at this time. The smaller anechoic spaces are used for testing with acoustic test fixtures. Acoustic test fixtures in Cincinnati include the French-German Institute de Saint Louis impulsive-noise test fixture, the Bacou-Dalloz ear muff test fixture and the Knowles Electronic Manikin for Acoustic Research (KEMAR). The PRL chamber has an ear-muff test fixture developed by Michaels and Associates in Pittsburgh.
  
  
• Education and training laboratory in Cincinnati with the capability to conduct studies using groups of participants examining training issues and evaluating materials including electronic and web-based training.
  
  
• Collaborative use of a 172 m3 anechoic chamber at the University of Cincinnati. The chamber is equipped with a 24-channel computerized data acquisition system. Engineering-grade sound power and sound energy level measurements of electric-powered hand tools are collected with a ten-microphone arrangement in an essentially free-field over a reflecting plane.
  
  
• Lab facilities also include metal working and carpentry shops with suitable equipment and hand tools. Expert technician support is also available for these shops. 

Field study capabilities include instrumentation for noise level assessments of complex noise exposures, impulsive noise recording and analysis, and audiometric testing, hearing protector fit-testing, and audiometric database analysis. The Hearing Loss Prevention Unit (HLPU), a mobile research facility, contains a four-person test room and is capable of conducting pure-tone audiometry and hearing protector fit-testing in field locations. It has been used at 42 sites nationwide to conduct over 5000 audiometric evaluations of more than 3600 workers. The mobile facility is also used for evaluation of training interventions.