Hearing conservation

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Workers in various industries are exposed to loud noises daily. Some of these industries include construction, manufacturing, farming, landscaping, and airport ground workers. Exposure to loud noise can have negative effects besides hearing loss. 

When the work environment is loud, employees may experience loss of concentration and annoyance leading to distraction. If workers are unable to concentrate and become distracted, not only can work productivity be affected, but they are at increased risk of having an accident. Therefore, it is important to keep noise at acceptable levels. Please see below for information regarding noise and ways to protect your employees.

  • Auditory effects of noise exposure:
    • Hearing loss.
    • Nerve damage.
    • Ringing in ears (tinnitus).
  • Temporary threshold shift:
    • Typically occurs from short exposure to loud noise.
  • Permanent threshold shift:
    • Typically occurs from long exposure to loud noise.
    • Risk of hearing loss increases dramatically as noise levels increase.
    • Levels above 115 dB for even 5 minutes are very risky:
    • Impact or banging noise above 140 dB will cause immediate damage to nerves.
  • Non-auditory effects of noise exposure:
    • Constriction of peripheral blood vessels.
    • Decrease in systolic blood pressure.
    • Increase in diastolic blood pressure.
    • Decreased respiration.
    • Fatigue.
    • Vertigo.
    • Stress.
    • Loss of concentration.
    • Annoyance and distraction.
  • Terminology:
    • Decibel (dB).
      • Measures sound intensity (sound pressure levels).
    • Hertz (Hz).
      • Measures the frequency of sound (number of complete cycles in one second).
    • Permissible exposure limit (PEL).
      • The legal limit of noise to which an employee may be exposed.
      • 90 dB over an 8-hour TWA.
    • Action level (AL):
      • Level of noise which requires action such as noise monitoring, audiometric testing, and a hearing conservation program.
      • 85 dB over an 8-hour TWA.
    • Standard threshold shift (STS):
      • Change in hearing threshold relative to the baseline audiogram of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear.
    • Time weighted average (TWA):
      • Average workplace exposure to noise using the baseline of 8 hours per day or 40 hours per week work schedule.
  • If two people, 3 feet apart, must shout to be heard the noise level is above 85 dB.
  • Hierarchy of controls:
    • Engineering:
      • Enclosures.
      • Barriers.
      • Acoustic materials.
      • Distance.
    • Administrative:
      • Job rotation.
      • Limit time.
    • Personal protective equipment (PPE):
      • Earplugs.
      • Earmuffs.
      • Canal caps.
      • Used when control methods are not feasible or use to supplement control methods:
        • Must be:
          • Available to all employees whose 8-hour TWA = or > 85 bB.
          • No cost to the employee.
          • Provide a variety of hearing protection (at least two different types).
          • Provide training on use and care of protection.
          • Ensure proper fit.
          • Supervise the correct use of all hearing protection.
          • PPE must reduce noise to below 90 dBA 8-hour TWA.
          • PPE must reduce noise to 85 dBA 8-hour TWA or below if an STS has been experienced.
  • OSHA Standards (29 CFR 1910.95—Occupational Noise Exposure) require employers to administer a continuing, effective hearing conservation program whenever employee noise exposures = or > 8-hour TWA of 85dBA.
    • Five Program Components:
      • Exposure monitoring:
        • Initial.
        • Change in production, process, equipment, or controls.
      • Audiometric testing:
        • Made available to all employees whose 8-hour exceeds 85 dBA.
        • No cost to the employee.
        • Provided within 6 months of first exposure at or above 85 dBA to establish a valid baseline audiogram, then annually thereafter.
        • Performed by a physician, certified audiologist, or otolaryngologist.
        • Test separately for each ear.
        • Compare annual audiogram to the baseline audiogram and determine if an STS has occurred.
        • If STS occurred, the employer may obtain retest within 30 days.
        • If STS occurred, the employee must be notified in writing within 21 days of the determination.
        • If STS occurred, the employee must be refitted and retrained in the use of hearing protection, unless the medical professional finds STS is not work-related.
        • If STS occurred, offer hearing protection with greater attenuation, unless the medical professional finds STS is not work-related.
      • Hearing protection:
        • Earplugs.
        • Earmuffs.
      • Employee training:
        • Must be conducted for all employees with 8-hour TWA of 85 dBA or more.
        • Repeated annually for each employee in the program.
        • Updated annually to include changes in PPE and/or work processes.
        • Must cover effects of noise, the purpose of protection, advantages/disadvantages & attenuation of types of protection.
        • Instructions on selection, fitting and care of protection.
        • Purpose of audiometric testing and test procedures.
      • Recordkeeping:
        • Keep audiometric testing records:
          • Name of employee.
          • Job classification.
          • Date of audiogram.
          • Examiner’s name.
          • Date of last audiometer calibration.
          • Most recent noise assessment.
          • Maintain accurate records of the measurements of the background sound pressure levels in audiometric test rooms.
        • Noise exposure measurements must be kept 2 years.
        • Audiometric testing records must be kept for the duration of employment.

 

KEMI does not assume liability for the content of information contained herein. Safety and health remain your responsibility. This information is to be used for informational purposes only and not intended to be exhaustive or a substitute for proper training, supervision or manufacturers’ instructions/recommendations. KEMI, by publication of this information, does not assume liability for damage or injury arising from reliance upon it. Compliance with this information is not a guarantee or warranty that you will be in conformity with any laws or regulations nor does it ensure the absolute safety of any person, place or object, including, but not limited to, you, your occupation, employees, customers or place of business.

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