The ambient noise levels in the test rooms affect the workers's hearing threshold. The present study was designed to assess the ambient noise levels in the test rooms to determine if valid hearing tests, both pure-tone air conduction and bone-conduction, could be performed in these environments.

In the present study, third octave band ambient noise sound pressure levels were measured in 124 audiometric test rooms used for clinical audiometry, and the results were compared with the ANSI third octave band maximum permissible ambient noise levels (MPANLs) for each test condition and frequency range.

The ambient noise SPLs were highest in the lower frequencies, and this decreased as the frequency increased. For the “ears covered” condition, about 24.2% of the rooms were in compliance (pass) with the MPANLs for the 125–8000 Hz, 35.5% were in compliance for the 250–8000 Hz range and 55.6% were in compliance for the 500–8000 Hz range. For the “ears not covered” condition, only about 8.1% of the rooms passed for the 125–8000 Hz, 13.7% of the rooms passed for the 250–8000 Hz range and 34.7% of the rooms passed for the 500–8000 Hz range. All 124 rooms met the OSHA MPANLs.

The results of this study strongly indicate that clinical audiometry is being conducted in test rooms having unacceptable or excessive ambient noise levels.