NOISE

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NOISE
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Noise - what is it?

• Unwanted sound
• sound is vibrations in air
• Sound Pressure Level
• decibels (dB) - sound loudness
• Frequency
• hertz (Hz) - vibrations per second
• Good human ears hear sounds between
• 20 to 20,000 Hz.

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Types of Noise

• Continuous
• same noise level over long periods
• Intermittent
• periods of quiet interrupted by noise
• most noise exposures are intermittent
• Impact or impulsive
• nail gun
• Most jobs have combinations of all noise types

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Is noise a big problem?

• 28 Million Americans affected
• NIOSH says 2.5 million workers/year are affected
• Over 500,000 construction workers are
  overexposed.
• 50 of construction workers may have some
  job-related hearing loss
• 33 of hearing loss is from NIHL
• A 25 year old construction worker has the hearing
  of a 50 year old without noise exposure
• Once hearing is gone, it is lost forever

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• Source Construction Safety Association of
  Ontario

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Construction Workers

• What does that mean to our workers
• How do we protect them
• Hierarchy of controls
• Common exposures
• jackhammer
• power tools
• heavy machinery

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You

• What does that mean to you?
• Loss of hearing through aging (presbycusis)
• Born with 40,000 cilia in ear canal
• Common Exposures
• iPods, headphones
• loud music/concerts
• hunting
• other

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Decibels

• Noise levels are measured in decibels (dBA)
• A small increase in decibels equates to a large
  increase in noise (logarithmic)
• An increase of just 3 dB doubles the amount of
  sound 88 dB can do twice as much harm to your
  ears as 85 dB. An increase of 10 dB means it is
  10 times louder
• Typical levels
• 65- normal conversation
• 75- busy street corner
• 85- background noise on a construction site

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How Do We Hear?

• Outer ear collects sound and vibrates eardrum
• Eardrum vibrates bones in middle ear
• Bones transmit vibrations to cochlea (inner ear)
• Cochlea hair cells are connected to auditory
  nerve that runs to the brain

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Effects of Noise

• Temporary Threshold Shift (TTS)
• temporary hearing loss
• early sign of a hearing problem
• recovery within hours after exposure

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Effects of Noise

• Permanent Threshold Shift
• permanent hearing loss
• destroys hair cells
• no treatment or cure
• gradual

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Effects of Noise

• Tinnitus - ringing in the ears
• Non-auditory problems
• Constant state of alert
• Disturbed sleeping patterns
• Increased blood pressure
• Presbycusis
• hearing loss from aging
• may be compounded by excess noise

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Effects of Hearing Loss

• Hearing loss makes it harder to communicate on
  the job, with friends and family, especially in
  noisy places like jobsites and restaurants
• Hearing loss can make it difficult to hear
  warning signs like back up alarms or traffic on a
  street

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Other Health Effects

• Make you feel tired/fatigued
• Heighten nervousness
• Raise in blood pressure
• Increase risks of heart problems
• May also effect sense of balance
• These effects are permanent

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What can you do?

• Turn down the volume
• When listening to music on earphones at a medium
  volume, the noise generated reaches up to 100dBA
• Loud enough to cause permanent damage after just
  15 minutes/day
• Use hearing protection
• Walk away
• 3 Foot Rule

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OSHA Requirements

• Construction 90 dBa
• General Industry 85 dB
• Hearing Conservation Program (1926.52)

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OSHA Table D-2 Permissible Noise Exposures
Duration per day, hours Sound Level dBA (slow response)
8 90
6 92
4 95
3 97
2 100
1.5 102
1 105
.5 110
.25 or less 115
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Task-Based Method

• ANSI A10.46-Hearing Loss Prevention in
  Construction and Demolition Workers
• When equipment or tasks expose workers to sound
  levels exceeding 85 dBA, engineering or
  administrative controls should be implemented
• Where controls are infeasible or fail to reduce
  sound levels below 85 dBA, HPDs shall be
  provided and used by employees

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Effective Hearing Conservation Program

1. Monitoring of employees noise exposures,
2. Engineering, work practice, and administrative
   controls,
3. PPE
4. Employee training and education
5. Baseline and annual audiometry,
6. Procedures for preventing further occupational
   hearing loss
7. Recording Keeping

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Hearing Protectors

• Ear Plugs
• Semi-Inserts
• Ear Muffs
• Attenuation

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Ear Plugs

• Formable
• Pre-molded
• Custom-molded
• Pros
• cooler in hot weather, cheaper
• Cons
• attenuation varies with fit
• easier to lose
• hygiene problems

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Ear Plugs

• To fit correctly, ear plugs must be inserted
  snugly into the ear canal.
• Make sure the foam plugs are rolled up tight and
  is crease free. Use the Roll model for
  practicing.
• Pull back gently on the ear with your opposite
  had to straighten out the canal while inserting
  the plug.

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Proper Fit

• Ear plug is snug in the ear canal

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Incorrect Fit

• Ear plug is not in snug and protection level is
  much lower

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Semi-Inserts

• Ear plug connected by headband
• Insert into the canal or cap over it
• Intended to be worn for short duration
• Pros
• easier to take on and off
• Cons
• uncomfortable for extended use
• smaller attenuation

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Ear Muffs

• Plastic cups attached by headband
• Pros
• easier to fit to most people, more consistent
  attenuation than plugs, can be fitted hardhats
• Cons
• heavier/hotter than plugs,
• headband pressure can make long wear uncomfortable