Hearing Conservation

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Hearing Conservation
Developed by Amanda R. Burg June 2006
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Background

• Exposure to high levels of continuous noise or
  sudden, impact noise can cause permanent hearing
  loss
• Noise induced hearing loss (NIHL) is 100
  preventable
• UWSPs program is designed to comply with OSHA
  standards and prevent work-related NIHL

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Definitions

• Noise unwanted any sound that provides no
  information
• Sound pressure variations in the air that can
  be detected by the ear
• Attenuation process of reducing sound to
  acceptable levels
• Sound pressure level of sound wave energy
  measured in decibels

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Effects of Noise

• Psychological
• Physiological
• Interference with communication, compromising job
  performance and safety

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Anatomy of the Ear
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Healthy Ear

• Hair cells located in the inner ear convert
  vibrations from sound waves into electrical
  signals and send them to the auditory nerve and
  finally to the brain.

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Damaged Ear

• Once hair cells in the inner ear are damaged,
  there is almost no regeneration and hearing
  ability is lost.

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Types of Hearing Loss

• Tinnitus ringing in the ears often times a
  precursor to hearing loss, caused by damage to
  the ends of hair cells in the inner ears
• Conductive Hearing Loss occurs when sounds do
  not travel through the outer ear to the middle
  ear efficiently
• Sensorineural Hearing Loss occurs when there is
  damage to the inner ear or to the nerve pathways
  to from the inner ear to the brain
• Mixed Hearing Loss combination of conductive
  hearing loss and sensorineural hearing loss

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How loud is too loud?
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OSHAs Occupational Noise Exposure Limits

• Time-Weighted Average (TWA) - a value, expressed
  in dB, which is calculated so that the resulting
  average is equivalent to an exposure resulting
  from a constant noise level over an 8-hour period
  
• 85 dB OSHAs Action Level, at an 8-hour Time
  Weighted Average (TWA), OSHA requires employers
  to have a hearing conservation program in place
  to monitor all employees who are exposed to this
  level of noise

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OSHAs Occupational Noise Exposure Limits

• 90 dB OSHAs Permissible Exposure Level, all
  employees exposed to an 8-hour TWA above 90 dB
  are required to wear hearing protection and
  employers are required to implement feasible
  engineering and administrative controls to
  decrease the risk of exposure
• 140 dB OSHAs Maximum Impact Level, exposure to
  impulsive or impact noise should not exceed 140
  dB at any time, regardless of duration

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Its always a good idea to wear hearing
protection during loud activities, even if noise
levels do not exceed the 85 dB TWA
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Noise Levels at UWSP
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OSHAs Occupational Noise Exposure Standard

• OSHAs Occupational Noise Exposure Standard
• CFR 1910.95
• requires six major components
• Measure and monitor noise levels
• Conduct audiometric testing of exposed employees
• Provide hearing protection through the use of
  PPEs, Engineering and Administrative controls
• Provide employee training
• Maintain a written program and keep records
• Allow employee access to information and records

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1 Measure Monitor Noise

• Employers should determine if noise levels are
  exceeding 85 dB
• Develop a detailed noise monitoring program and
  notify employees of the hazard if noise levels
  are exceeding 85 dB
• Allow employees or their representatives the
  opportunity to observe any noise measurements
  conducted

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2 Audiometric Testing

• Employers should establish and maintain an
  audiometric testing program and make it available
  to all employees whose exposure equals or exceeds
  an 8-hour TWA of 85 dB
• Baseline and annual audiograms are required and
  are to be done by a certified audiometric
  technician baseline tests should be conducted
  within the first six months of the employees
  exposure
• 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
• The results should be evaluated if a Standard
  Threshold Shift (STS) occurs. STS when there is
  a change in a persons hearing threshold of 10 dB
  or more in either ear

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3 Hearing Protection

• Employers should make hearing protectors
  available to all employees exposed to an 8-hour
  TWA of 85 dB or greater
• Hearing protectors shall be available at no cost
  to the employee and shall be replaced as
  necessary
• Employers shall ensure that hearing protection
  are worn by
• Any employee over the PEL of 90 dB
• Any employee who is exposed to an 8-hour TWA of
  85 dB or greater and who
• Has not had a baseline audiogram established or
• Has experienced a threshold shift
• Employees shall be given the opportunity to
  select their hearing protectors from a variety of
  types provided by their employer, employers will
  also provide training and fitting

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4 Employee Training

• The employer shall institute a training program
  for all employees who are exposed to noise at or
  above an 8-hour TWA of 85 dB and ensure
  participation in the program
• The program shall be repeated annually for each
  employee included in the hearing conservation
  program, it should be updated to reflect changes
  in work processes and protective equipment
• The employer shall ensure that each employee is
  informed of the following
• The effects of noise on hearing
• The purpose of hearing protectors, the
  advantages, disadvantages, and attenuation of
  various types, and instructions on selection,
  fitting, use and care and
• The purpose of audiometric testing, and an
  explanation of the test procedures

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5 Written Program Record Keeping

• Employers should maintain an accurate record of
  all employee exposure measurements as required by
  the Monitoring, 1910.95 (d) section of the OSHA
  standard
• The employer shall retain all employee
  audiometric test records as required by the
  Audiometric Testing Program, 1910.95 (g)
  section of the OSHA standard
• Records shall be retained for at least the
  following periods
• Noise exposure measurement records shall be
  retained for at least two years
• Audiometric test records shall be retained for
  the duration of the affected employees employment

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6 Access to Information

• All records required by the OSHA standard shall
  be provided upon request to employees, former
  employees, or representatives designated by the
  individual employee
• The employer shall make available to affected
  employees or their representatives copies of CFR
  1910.95 (OSHAs Occupational Noise Exposure
  Standard) and shall also post a copy in the
  workplace

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Occupational Noise Exposure Limits

• For unprotected ears, the permissible exposure
  limit decreases by ½ for every 5 dB increase in
  the average noise level.
• For example, exposure is limited to
• 8 hours a day at 90 dB
• 4 hours a day at 95 dB
• 2 hours a day at 100 dB
• 1 hour a day at 105 dB

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Hearing Protection DevicesEarplugs
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Earplugs

• Disadvantages
• requires more time to fit
• more difficult to insert and remove
• requires good hygiene practices
• may irritate the ear canal
• easily misplaced

• Advantages
• small and easily carried
• convenient to use with other PPEs (can be worn
  with earmuffs)
• more comfortable for long-term wear in hot, humid
  work areas
• convenient for use in confined areas

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Hearing Protection DevicesCanal Caps
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Canal Caps

• Advantages
• Convenient to put on and take off
• Not easily misplaced or lost
• Easily stored around users neck when not in use

• Disadvantages
• Some people find the pressure from the bands
  uncomfortable
• Earplugs may be a poor fit, blocking little of
  the hazardous noise

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Hearing Protection DevicesEarmuffs
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Earmuffs

• Advantages
• designed so that one size fits most head sizes
• easily seen at a distance to help monitor use
• not easily misplaced or lost
• less attenuation variability among users

• Disadvantages
• less portable and heavier
• more inconvenient for use with other PPEs
• more uncomfortable in hot, humid work areas
• more inconvenient while working in confined spaces

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Hearing Protection Device Care

• Follow the manufacturers instructions
• Check hearing protection regularly for wear and
  tear
• Replace cushions or earplugs that are no longer
  pliable
• Replace a unit when headbands are so stretched
  that they do not fit snugly against the head
• Disassemble earmuffs to clean
• Use a soft brush to remove oil and dirt that can
  harden cushions
• Wash earplugs and cushions with mild soap and
  water and place them on a clean surface to dry

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The Noise Reduction Rating

• The Noise Reduction Rating (NRR) is a rating
  given to hearing protection devices.
• The NRR is used to estimate how well the device
  reduces noise, the higher the number the greater
  the noise reduction.

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The Noise Reduction Rating

• The formula to determine real life NRR
  according to OSHA
• Lmeasured (NRR - 7 dB) LHPD
• For example, your ear plugs have an NRR of 25
  and you are exposed to 95 dB, so
• 95 (25 - 7) 77 dB
• So if you wear hearing protection as directed,
  100 of the time during noisy work, your
  exposure will decrease from 95 dB to 77 dB.

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Using Ear Plugs

• Step 1
• Squeeze the plug along its length and roll it
  between your thumb and forefinger to compact it
  down for insertion into the ear canal.

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• Step 2
• Keeping the ear plug compressed and rolled, reach
  over and behind your head with your opposite hand
  and gently pull your ear slightly out and back to
  straighten out the ear canal.

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• Step 3
• Insert the plug into the ear canal.  You may have
  to keep a finger on the plug for a few seconds to
  let it expand to the size of your ear canal.  Do
  not insert the plug so deeply that you cannot
  pinch a bit of the plug for removal practice
  the insertion a few times in front of a mirror to
  get familiar with proper insertion depth.

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• Properly inserted earplugs will be easily visible
  from the sides, but only a very small portion of
  the plug will project from the ear.

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• Very little (if any) of the earplug should be
  visible from a straight-on view. 

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Choosing Hearing Protection

• Choosing a type of hearing protection is a
  personal one and depends on factors including
• level of noise
• comfort
• the suitability of the protection for the work
  environment
• At UWSP, you can contact your supervisor for a
  selection of hearing protectors for you to use
  free of charge.

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Common Excusesfor not wearing hearing protection

• I cant hear other workers.
• At high noise levels, hearing becomes overloaded.
  Reducing overall sound levels allows the ear to
  operate more effectively in much the same way
  sunglasses provide improved vision in bright
  conditions.

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Common Excusesfor not wearing hearing protection

• My machine sounds different.
• This is true, but workers will become accustomed
  to the new sound and will be able to monitor the
  sound of their machines as well at the end of the
  day as at the start of the shift.

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Common Excusesfor not wearing hearing protection

• Im used to the noise.
• Exposure to noise does not toughen ears. Ears
  do not become used to noise, they become deaf.

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Common Excusesfor not wearing hearing protection

• Protectors are uncomfortable.
• Like new shoes, new hearing protectors need a
  period of adjustment. If discomfort persists,
  the device should be exchanged for a different
  size, fit or type which will be more
  comfortable.

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Common Excusesfor not wearing hearing protection

• Ive already lost some of my hearing, why should
  I wear hearing protection now?
• Just because youve lost some of your hearing
  doesn't mean youre protected for losing more or
  all of it. Although hearing protection devices
  cannot restore a noise-induced hearing loss, they
  should prevent additional losses from occurring.

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Simple ways to reduce yourrisk of NIHL everywhere

• Be aware of and avoid harmful noise.
• Use hearing protection.
• Minimize your total daily exposure to noise.
• Control the volume when you can.
• Do not wait until you notice hearing loss to
  start protecting yourself from harmful noise.

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