Ms. Kathleen Brunell, RN
All Saints Medical Group
2405 Northwestern Ave.
Racine, WI 53404
Dear Ms. Brunell:
Thank you for your July 8, 2004 letter to the Occupational Safety and
Health Administration (OSHA) regarding audiometric testing rooms and
compliance with the Occupational Noise standard, 29 CFR 1910.95. In your
letter, you have specifically asked how often the audiometric testing
room must be evaluated per the specifications in Appendix D of the
Occupational Noise standard. This letter constitutes OSHA's
interpretation only of the requirements discussed and may not be
applicable to any question not delineated within your original
The intent of the ambient noise level requirements in the OSHA standard
is to assure that the hearing test is conducted in an environment that
will assure valid and accurate test results. Paragraph 1910.95(h)(4)
requires that audiometric examinations be administered in a room meeting
the requirements listed in Appendix D. This implies that the test
environment must be in compliance with the stated background levels
every time an audiometric test is performed.
There are different types of testing environments utilized in hearing
conservation programs (i.e., sound-proof booth, mobile van, and an open
room. However, every audiometric test must be performed in rooms meeting
the requirements listed in Appendix D so that measured thresholds
between tests reflect real hearing change rather than measurement error.
For a sound booth that never moves once it is stationed, the ambient
noise levels may not need to be measured more than once a year,
typically at the time of the annual and/or exhaustive calibration.
However, an evaluation should also be done if there are changes in the
outside environment that could have changed the internal ambient
background levels. Equipment is available that performs ambient noise
level monitoring continuously during hearing testing. Also, newer
computerized audiometers frequently incorporate the ambient noise level
monitoring into the hearing test itself and will only accept responses
to test signals when the ambient noise is within acceptable limits.
To meet the requirements of Appendix D for a mobile van, as a minimum,
it may be necessary to do ambient testing whenever the van is relocated
to a new location at a minimum. To ensure that the hearing test results
are valid each time, it is advisable to check ambient noise levels every
day you do audiometric testing along with the daily calibration check
using a bioacoustical simulator. As stated above, you may also use the
newer computerized audiometers that incorporate ambient noise level
monitoring into the hearing test itself. If you notice changes in the
external environment, such as greater truck traffic, you might also
consider moving the van to a quieter location.
Conducting audiograms in an open room environment can also be difficult.
Noise levels can change constantly depending on what is going on in the
immediate surrounding area (i.e., outside traffic, air conditioning
going on and off, disturbing noise from the clanking of shoes, phones
ringing, etc.). In this situation, background levels may need to be
monitored whenever an audiometric test is administered.
Thank you for your interest in occupational safety and health. We hope
you find this information helpful. OSHA requirements are set by statute,
standards, and regulations. Our interpretation letters explain these
requirements and how they apply to particular circumstances, but they
cannot create additional employer obligations. This letter constitutes
OSHA's interpretation of the requirements discussed. Note that our
enforcement guidance may be affected by changes to OSHA rules. Also,
from time to time we update our guidance in response to new information.
To keep apprised of such developments, you can consult OSHA's website athttp://www.osha.gov.
If you have any further questions, please feel free to contact the
Office of Health Enforcement at (202)693-2190.
Richard E. Fairfax, Director
Directorate of Enforcement Programs