NOTE: Although the first three (3) pages of this OSHA Instruction
CPL 2-2.35A have been cancelled, Appendix A is still vaild.
Appendix A
Noise Control Guidelines
When comparing the relative degree of attenuation of personal protectors
and engineering and/or administrative controls, all of the following
factors in addition to the guidelines in the Field Operations Manual and
Industrial Hygiene Field Operations Manual must be considered and
documented in the case file:
1. Hearing Protection. Personal hearing protection must attenuate
the occupational noise received by the employee's ears to
within the levels specified in Table G-16 of 29 CFR 1910.95.
For those employees with a standard threshold shift (STS),
noise reduction must be sufficient to meet Table G-16a of 29
CFR 1910.95 (85 TWA). Hearing protectors shall be evaluated
for the purposes of analyzing the benefits of engineering
controls as follows:
a. Use Appendix B of 29 CFR 1910.95 to determine the
laboratory-based noise reduction for a given hearing
protector.
b. Apply a safety factor of 50 percent; i.e., divide the
calculated laboratory-based attenuation by 2.
NOTE: This is a general method for taking into
consideration OSHA experience and the published
scientific literature, which indicate that
laboratory-obtained attenuation data for hearing
protectors are seldom achieved in the workplace.
If a different safety factor seems appropriate in a
particular instance, the ARA for Technical Support
should be consulted for assistance. This procedure
is not applicable, however, for determining
compliance with the hearing protector attenuation
requirements of the hearing conservation amendment
(29 CFR 1910.95(j)).
c. The adjusted noise reduction should be sufficient to meet
Table G-16 or, as appropriate, Table G-16a. Depending on
the specifics of the case, an exception may be
appropriate when an employer is in compliance with the
hearing conservation amendment and has a history of an
effective hearing conservation program.
2. Hearing Loss. Documentation of any hearing loss shall include:
a. The amount of hearing ability lost and date it was
recorded.
NOTE: If the employer has not done so, apply age
correction to audio-grams according to the
guidelines in Appendix F of 29 CFR 1910.95.
b. Exposure level.
c. Frequency and duration of exposure.
d. Length of employment.
e. Explanation of any followup measures taken.
f. Any other pertinent information.
3. Cost of Controls.
a. Resonability. The estimated costs for engineering controls
must be reasonable and include the annualized cost of installing
controls and, if available, the annual cost of their maintenance
and costs due to any resulting loss of productivity or effeciency.
b. Relative Permanency. In order to consider the permanency of
engineering controls, compare the estimated cost for engineering
controls to the estimated annual cost of a hearing conservation
program multiplied by the approximate number of years the controls
would be effective.
4. Employee Noise Reduction by Controls. An anticipated reduction
in employee noise exposures would be considered significant if a 3 to
5 dB decrease is achieved by one or a combination of the following:
a. Source controls.
b. Controlling the industrial environment (e.g., barriers,
enclosures, etc.).
c. Administrative controls.
5. Control Options. When evaluation control options for the purposes
of this instruction, consider all types of abatement possibilities.
For example:
a. Partial Use of Controls. It may be beneficial to implement
some of the controls while forgoing more costly ones.
b. Substitution. Abatement plans may include plans for replacing
process equipment with quieter equipment that will significantly
reduce exposure levels and make interim engineering controls for
existing machinery impractical.