Intranet graphic Business Policy Letters


TO: All Members of the University Community 97:38
DATE: September 1997

HEARING CONSERVATION POLICY
(Supersedes 91:3)

  1. PURPOSE

    The purpose of these rules and procedures is to protect the health and safety of University employees who must work in environments where they are exposed to excessive noise. Specific rules and procedures are established to ensure employees are provided with the necessary personal hearing protection when working in hazardous noise conditions.

    These rules and procedures are established in compliance with OSHA regulations 29CFR1910.95, Occupational Noise Exposure, which requires the establishment of a hearing conservation program.

  2. SCOPE

    These rules and procedures shall apply to all University employees while working on property owned or leased by Ferris State University.

  3. PROGRAM ADMINISTRATION

    The Environmental Health and Safety Office is responsible for the overall administration of the University's Hearing Conservation Program. All University management and supervisory personnel shall provide full support and cooperation with the Environmental Health and Safety Office in carrying out their assigned functions in the program.

  4. DEFINITIONS

    1. "Action Level" means an eight-hour, time-weighted average noise exposure of 85 decibels measured on the A-scale, slow response, or equivalently, a dose of 50%.
    2. "Audiogram" means a chart, graph, or table resulting from an audiometric test showing an individual's hearing threshold levels as a function of frequency.
    3. "Baseline audiogram" means the audiogram against which future audiograms are compared.
    4. Decibel" or "dB" means a unit of measurement of sound pressure level.
    5. "Noise dose" means the ratio, expressed as a percentage, of the time weighted integral, over a stated time or event, of the 0.6 power of the measured, slow, exponential time-averaged, squared A-weighted sound pressure and the product of the criterion duration (eight hours) and the 0.6 power of the squared sound pressure corresponding to the criterion sound level (90dB).
    6. "Noise Dosimeter" means an instrument that integrates a function of sound pressure over a period of time in such a manner that it directly indicates a noise dose.
    7. "Sound level" means ten times the common logarithm of the ratio of the A-weight sound pressure to the square of the standard reference pressure of 20 micropascals and is expressed in units of dBA.
    8. "Standard threshold shift" means a change in the hearing threshold relative to the baseline audiogram of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear.
    9. "Time-weighted average sound level" means that sound level which, if constant over an eight-hour exposure, would result in the same noise dose as is measured.
    10. "TWA" means time-weighted average.

  5. PROTECTION FROM NOISE EXPOSURE

    1. Protection against the effects of noise exposure shall be provided when the sound levels exceed those shown in Table 1 when measured on the A-scale of a standard sound level meter at slow response.

      Table 1 - Permissible Noise Exposures
      Duration Per Day Hours Sound Level dBA Slow Response
      8 90
      7 91
      6 92
      5 93
      4 95
      3 97
      2 or less 100
    2. The maximum permissible level for impact or impulse noise shall be 140 dB as measured with a sound level meter capable of indicating an instantaneous peak noise level. Impact and impulse noise are peaks or maxim of sound level, above the continuous background level, which have separation intervals greater than one sound. If peaks are done one second or less apart, the noise shall be considered to be continuous.
    3. Employees whose noise exposures equal or exceed the action level shall be subject to the provision of this hearing conservation program, shall be provided with the necessary hearing protection, and shall comply with the rules and procedures.

  6. NOISE MONITORING

    1. When information indicates that any employee's noise exposure may equal or exceed the action level, the Environmental Health and Safety Office shall under-take noise monitoring to identify employees for inclusion in the hearing conservation program.
    2. Where circumstances such as high worker mobility, significant variations in sound level, or a significant component of impulse or impact noise make area monitoring generally inappropriate, representative personal monitoring shall be used unless it can be shown that area monitoring produces equivalent results.
    3. Noise monitoring shall be repeated when a change in equipment, work schedule or controls increases noise exposure so that additional employees may be exposed at or above the action level or to the extent that the attenuation provided by hearing protectors being used by employees may be rendered inadequate.
    4. The Environmental Health and Safety Office shall provide affected employees an opportunity to observe any noise measurements. Each employee exposed at or above the action level shall be notified of the results of the monitoring pertaining to that employee.
    5. Noise exposure determinations shall be made in accordance with Michigan's Occupational Noise Exposure Standards adopted by the Michigan Health Standards Commission.

  7. AUDIOMETRIC TESTING

    1. The University, at no cost to employees, shall make audiometric testing available to all employees whose noise exposure equal or exceed the action level.
    2. The audiometric testing program including the persons conducting the tests, the audiograms, evaluation of audiograms, test procedure, test equipment calibration, and follow-up procedures shall meet the applicable requirement of Michigan's Occupational Noise Exposure Standards adopted by the Michigan Occupational Health standards Commission.
    3. Within six months of an employee's first exposure at or above the action level, a baseline audiogram shall be established against which subsequent audiograms can be compared. Testing to establish a baseline audiogram shall be preceded by a period of not less than 14 hours without exposure to workplace noise. Hearing protectors may be used as a substitute for the requirement of 14 hours without exposure to workplace noise. Employees shall be notified of the need to avoid high levels of non-occupational noise exposure during the 14-hour period immediately preceding the audiometric examination.
    4. At least annually after obtaining the baseline audiogram, a new audiogram shall be obtained for each employee exposed at or above the action level.
    5. Each employee's annual audiogram shall be compared to that employee's baseline audiogram to determine if the audiogram is valid and if a standard threshold shift has occurred. If the annual audiogram shows that the employee has suffered a standard threshold shift, a retest may be obtained within 30 days and the retest considered as the annual audiogram. An audiologist, octolaryngologist, or physician shall review problem audiograms and shall determine whether there is need for further evaluation.
    6. If a comparison of the annual audiogram to the baseline audiogram indicates a standard threshold shift has occurred, the employee shall be informed of this fact, in writing, within 21 days of the determination. Unless a physician determines that the standard threshold shift is not work related or aggravated by occupational noise exposure, the following actions shall be taken:
      1. Employees not using hearing protectors shall be fitted with hearing protectors, trained in their use and care, and required to use them.
      2. Employees already using hearing protectors shall be refitted and retrained in the use of hearing protectors and provided with hearing protectors offering greater attenuation if necessary.
      3. The employee shall be referred for a clinical audiological, evaluation or an otological examination, as appropriate, if additional testing is necessary or if it is suspected that a medical pathology of the ear is caused or aggravated by the wearing of hearing protectors.
      4. The employee is informed of the need for an otological examination if the medical pathology of the ear that is unrelated to the use of hearing protectors is suspected.
      5. If subsequent audiometric testing of an employee whose noise exposure is less than the permissible eight-hour, TWA of 90, dB indicates that a standard threshold shift is not persistent, the employee shall be informed of the new audiometric interpretations and the required use of hearing protectors discontinued.
    7. An annual audiogram may be substituted for the baseline audiogram when, in the judgement of the audiologist, otolaryngologist, or physician who is evaluating the audiogram is persistent or the hearing threshold shown in the annual audiogram indicates significant improvement over the baseline audiogram.

  8. HEARING PROTECTORS

    1. Hearing protection shall be made available to all employees exposed to noise at or above the action level. Hearing protectors shall be replaced as necessary.
    2. Hearing protectors shall be worn by the following:
      1. Employees who are exposed at or above the permissible level.
      2. Employees who are exposed at or above the action level but less than the permissible level and who have not yet had a baseline audiogram taken or have experienced a standard threshold shift.
    3. Employees shall be given the opportunity to select their own hearing protectors from a variety of suitable hearing protectors provided by the University.
    4. The University shall provide training in the use and care of all hearing protectors provided to employees.
    5. The University shall ensure proper initial fitting and supervise the correct use of all hearing protectors.
    6. Hearing protector attenuation shall be evaluated in accordance with the provision of Michigan's Occupational Noise Exposure Standards.

  9. EMPLOYEE TRAINING PROGRAM

    1. All employees who are exposed to noise at or above the action level shall participate in a hearing conservation training program conducted by the Environmental Health and Safety Office.
    2. The training program shall be repeated annually for each employee included in the hearing conservation program. Information provided in the training program shall be updated to be consistent with change in protective equipment and work processes.
    3. The training program shall include the following:
      1. The effects of noise on hearing.
      2. The purpose of hearing protectors: the advantages; disadvantages, and attenuation of various types of hearing protectors; and instructions on the selection, fitting, use, and care of hearing protectors.
      3. The purpose of audiometric testing, and an explanation of the test procedure.

  10. RECORDKEEPING

    1. The Environmental Health and Safety Office shall maintain an accurate record of all employees' exposure measurements.
    2. The Environmental Health and Safety Office shall maintain an accurate record of all employee audiograms obtained pursuant to these rules and procedures. These records shall include all of the following information:
      1. Name and job classification of the employee
      2. Date of the audiogram
      3. Examiner's name
      4. Date of last acoustic or exhaustive calibration of the audiometer
      5. Employee's most recent noise exposure assessment
    3. Noise exposure records shall be retained for 2 years. Audiometric test records shall be retained for the duration of the affected employee's employment.
    4. All records shall be provided, upon request, to employees, former employees, and representatives designated by the individual employee.
Richard Duffett, Vice President
Administration and Finance

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