1. OCCUPATIONAL NOISE
STACY ARVINNA
GROUP 3
4TH YEAR 1ST SEM
11 JANUARY 2011
HYGIENE SUBJECT

2. SOUND VERSUS NOISE
 Sound is a pressure change detectable by the
human ear.
 The pitch ranges between 20 to 20,000 Hz.
 The volume ranges between 0 to 140 dB.
 Noise is a type of sound.
 It carries no information.
 It is random.
 It is generally described as undesirable or unwanted
sound.

3. AN EAR’S ANATOMY
HOW WE HEAR?
Ear
 Outer ear - directs
sound waves
 Middle ear -
eardrum -
hammer, anvil,
stirrup
 Inner ear - organ
of corti, cochlea

4. OCCUPATIONAL NOISE
 Noise is defined as unwanted sound.
 Transit workers who operate, service, or
maintain vehicles, equipment, or facilities may
be routinely exposed to high levels of noise.
 Working in maintenance shops or repairing
buses involves using loud machinery such as
motors, grinders, saws, presses, pneumatic
equipment and hand held tools can also generate
high noise levels.

6. NOISE ON HEARING
 Sound - produced vibrations enter
the inner ear as waves.
 Frequency - (pitch) number of
vibrations per second; measured in
hertz (Hz)
 Intensity - loudness of the sound;
measure in decibels (dB).

7. EFFECT OF OCCUPATIONAL
NOISE
 Exposure to excessive noise levels at work can
result in two types of noise induced hearing loss
(NIHL):
 Temporary (conductive) hearing loss occurs when
sound vibrations are blocked from reaching the inner ear.
This may be due to wax buildup, an infection of the
middle ear, or explosive sounds that damage the eardrum
or middle ear. This type of hearing loss is reversible. The
ear may recover on its own or it may be surgically
corrected.
 Permanent (sensineural) hearing loss occurs when
cells and nerves in the inner ear are damaged.
Individuals don’t realize they are experiencing hearing
loss because it happens gradually. It cannot be corrected
or reversed.

8. SIGNS AND SYMPTOMS OF
HEARING LOSS
 Ringing / buzzing in the ears
 Difficulty with high pitched sounds
 Problems with conversing with others
 Inability to hear consonants
 Raising the volume on the TV / radio

9. TYPES OF HEARING LOSS
 Middle ear hearing loss results from lack of
conduction.
 Impacted wax
 Broken ear drum
 Inner ear hearing loss results from lack of neural
connections.
 Naturally due to aging
 Loud noises
 Disease

10. OCCUPATIONAL HEARING
LOSS
 Noise-Induced
Hearing Loss or Noise-
Induced Permanent Threshold Shift
(NIPTS)
 Permanent sensor neural condition
 Cannot be treated or corrected medically
 Initially effects high frequencies
 Industrial trough
 Speech recognition
 Progresses to lower frequencies

11. EFFECT OF OCCUPATIONAL NOISE
 Exposure to excessive noise levels at work
can also result in:
 Increased stress levels that may raise blood
pressure and contribute to heart disease. High
noise levels can also cause insomnia, fatigue,
irritability, and decreased job performance.
 Increased risk of accidents because high noise
levels make it more difficult to hear other
workers, to hear warnings or approaching
vehicles, or to be heard by other workers.

12. NON-AUDITORY EFFECTS OF NOISE
 Effects cardiovascular system
 Effects the nervous system
 Interferes with speech and concentration
 Causes annoyance, stress, and fatigue
 Reduces work efficiency
 Lowers morale
 Masks warning sounds

13. THRESHOLD
SHIFTS
 Temporary Threshold Shifts (TTS)
 Hearing returns to normal after noise exposure
 Permanent Threshold Shifts (PTS)
 Repeated noise exposure without a return
to normal
 Standard Threshold Shifts (STS)
 > 10 dB average loss in 2000, 3000, or 4000 Hz in either
ear

14. NOISE LEVEL AND THE HUMAN
RESPONSE
 Pneumatic chipping and riveting 130dB(A)
 Automatic punch press 110 dB(A)
 Heavy lorries at 6m 90
dB(A)
 Construction site - pneumatic drilling 90 dB(A)

15. NOISE MEASURING EQUIPMENT
 Sound level meters
 Basic instrument to measure
sound pressure variations in
air
 Noise dosimeter
 Combines sound pressure
and time for
employee
exposure monitoring

16. NOISE MEASURING EQUIPMENT
 Octave band analyzer
 Diagnostic tool to help find appropriate
engineering controls to reduce noise levels

17. AUDIOMETRIC TESTING
 A qualified person performs the hearing test, usually
an audiologist.
 The audiometers are calibrated to determine your
threshold of hearing and changes (threshold shifts).
 Must meet strict specified criteria
 A qualified person interprets the results of the
hearing test.

18. AUDIOMETRIC TESTING
 Painless and short test to measure hearing
 Establishes a baseline
 Detects changes in hearing
 Employee’s with exposure in excess of 85dB(A)
over an 8 hour period

19. NOISE REDUCTION RATING
 Defined as the maximum number of decibels (dB) that
the hearing protector will reduce the sound level when
worn
 NRR must be on the hearing protector package.
 NRR example for A-weighted data
 Estimated exposure (dBA) = TWA (dBA) - (NRR - 7)

20. HEARING CONSERVATION
Quite Room: 30 dBA
Bulldozer: 85dBA
Normal City Noises: 65 dBA
Normal Conversation: 50 dBA
Artillery/Good Rock Band: 120 dBA

21. HEARING PROTECTION
 Three ways to protect your hearing:
Engineering controls
Administrative controls
Personal Protective Devices

22. ENGINEERING
CONTROLS
 Engineering Controls
 Engineering controls reduce noise at its source.
Examples include:
 enclosing noisy machinery, fans, or motors, or moving
them away from workers
 controlling vibration by damping or by tightening,
lubricating, or isolating vibrating parts
 replacing loud machines with quiet machines
 installing sound barriers or sound- absorbing
materials
 Equipment and exhaust

23. ADMINISTRATIVE
CONTROLS
 Decreasing the exposure time
 Limiting the number of personnel
exposed
 Arranging a work roster system

24. EUROPEAN COMMUNITY 1990
REGULATIONS
 Objectives
 Protect workers from risks to their hearing caused by noise.
 Prevent hearing loss and deafness as a result of exposure to
noise at work.
 Legal requirements placed on employers
 Identify noise problems and if noise levels are above 85dB(A),
measurements must be taken and assessed by a competent
person. Such measurements should be repeated at
appropriate intervals.

25. EUROPEAN COMMUNITY 1990
REGULATIONS
 General duty to reduce the level of noise exposure by
engineering or administrative means.
 If noise level is above 85dB(A):
 Inform employees of the noise levels present and
measures taken to reduce exposure.
 Make ear protection available and provide training in its
use
 Hearing checks must be made available to employees
exposed to noise levels in excess of 85dB(A) over an 8
hour period

26. EUROPEAN COMMUNITY 1990
REGULATIONS
 If noise level is above 90dB(A) the noise requirements
for 85dB(A) apply plus:
 Identify reasons for excess noise and put a plan in place to
reduce.
 Identify and clearly designate hearing conservation zones.
 Ear protection must be worn and its use supervised.
 Employees must be trained in the hazards of noise and the
correct use of hearing protection.

27. NOISE LIMIT
 No employee shall be exposed above the
permissible exposure level (PEL).
 PEL = 90 dBA for a 8-hour time-weighted average
(TWA)
 Feasible administrative or engineering controls are
required.
 Hearing protection is required to protect the
employee to the PEL.

28. NOISE ACTION
LIMIT
 Action Level (AL) = 85 dBA for a 8-hour TWA
 Determined without regard to hearing protector
attenuation
 Hearing Conservation Program (HCP) required
 Hearing protection devices must be available

29. MONITORING
 Strategy to identify all employees who could be
exposed above AL (85 dBA)
 Conduct representative sampling
 Each job classification
 All shifts
 Repeat monitoring when:
 Additional employees are exposed
 Hearing protectors are inadequate

30. TRAINING
 Must be annual
 Must include:
 Effects of noise on hearing
 Purpose of hearing protectors
 Instruction in protector hearing protector selection, fitting,
use and care
 Purpose of audiometric test and explanation of the
procedures and results

31. POSTING THE STANDARD
 The employer shall make available to affected
employees or their representatives copies of the
standard.
 The employer shall also post a copy of the standard in
the workplace.

32. RECORDKEEPING
 Provide employee and DOL access and transfer records
to successor employer
 Noise measurements: > 2 years
 Audiometric tests > employment duration:
 Name, job classification and dBA-TWA
 Date, examiner’s name and calibration date
 Background measurements of audiometric test
room

33. PERSONAL PROTECTIVE
DEVICES
Hearing protective devices (HPDs) may be used
as a last resort, if engineering or
administrative controls are ineffective or not
feasible. Examples include earmuffs and
earplugs. HPDs are required to be labeled with
a noise reduction ratio (NRR). The NRR is the

34. HEARING PROTECTORS
 Shall be available to “action level” employees
 Shall be required for those employees:
 Exposed at or above 90 dBA
 Exposed at or above 85 dBA (without an audiometric
baseline)

35. HEARING
PROTECTORS
 Provided at no cost to the
employee
 Selected from a variety of
types and brands
 Properly fitted
 Replaced as necessary

36. “EAR PLUGS”
HEARING PROTECTORS
“EAR PLUGS”
 These devices fit into the ear canal between the outer and
middle ear and block the sound from reaching the sensitive
inner ear.
 (i) Made of foam material that is rolled and inserted, expands
to fit snugly and can be custom made.
 (ii) Wash hands, roll and compress into a cylinder. Reach one
hand around the back of the head and pull ear up and out.
Insert into the ear canal. Hold in place until it begins to
expand and excludes noise.
 (iii) Inspect before insertion and discard if damaged or dirty.
 (iv) Small, inexpensive, portable, comfortable in warn
weather, disposable, can hear others speaking.
 (v) Requires a good fit, cannot be inserted with dirty hands,
cannot be worn with ear infections, might become loose over
time.

37. “EAR MUFFS”
HEARING PROTECTORS
“EAR MUFFS”
 This style protector consists of cups which fit over the entire
outer ear to help seal out noise. May be connected to the hard
hat or held together by a head band.
 (i) Cushioned caps connected by a spring loaded headband.
 (ii) Adjust the headband to ensure that the seals are in
complete contact with the head. Ensure the ear cup fits over the
entire outer ear. Wear eyeglass frames with temple cushions
that will not break the seal of the muffs.
 (iii) Wipe cushions when they become soiled. Replace if stiff,
worn, cut or torn.
 (iv) Can be worn with ear plugs for extreme noise exposure.
Reduction of approximately 50 dBA. Easy to put on and remove.
Can be worn despite ear infections.
 (v) Bulky and can be uncomfortable in warm weather.

38. PROTECTOR ATTENUATION
 Hearing protectors shall:
 For overexposed employees
 Attenuate < 90 dBA 8-hr TWA
 For employees with an STS
 Attenuate < 85 dBA 8-hr TWA
 Whenever noise exposures increase
 Be reevaluated to determine adequacy

39. WHAT IS NOISE
 Noise is an unpleasant / unwanted sound
 Hearing and how noise effects it
 Types of noise
 continuous
 impulse
 Side effects of noise
 loss of hearing
 stress
 accidents
 behavioral effects
 negative impact on health

40. SUMMARY
 Know the source of harmful noise
 Use engineering and administrative
controls to avoid exposure to noise
 Obey posted high noise area signs
 Wear hearing protection properly