Call Girls Siliguri Just Call 9907093804 Top Class Call Girl Service Available
Occupational noise
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.
5.
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
Editor's Notes
(Illustration: OSHA.gov)
Illustration: The Ear Foundation accessed from WWW.OSHA.gov
Sound travels at a speed of about 340 meters per second. An example of low vs. high frequency: 1) The exhaust from a slowly revolving tugboat engine produces a soft, thudding low-frequency noise. 2) An outboard motor, on the other hand, has a higher frequency sound because of the rapidly repeated pressure shocks it produces. The higher the frequency, the greater effect on the ear. Intensity is measured by how much pressure a sound exerts on a surface. Noises that are loud and high-pitched have the worst effect on hearing. The next two foils give examples of sounds and their intensity.
Illustration: Microsoft Clip Art
Illustration: Microsoft Clip Art
Illustration: Microsoft Clip Art
Sound is measured in decibels. Permanent hearing loss can be caused by continuous exposure to noise greater than 85 dBA. Short exposure to very loud noise greater than 140 dBA this causes the pain response. If you double the intensity of the sound you increase it by 3 dB. This is the 3 dB rule (e.g. 90 dBA + 90 dBA = 93 dBA).
Photo: OSHA
Photo: OSHA
Audiometry testing is totally painless and only takes a few minutes. A baseline of hearing is established to: - detect any hearing loss prior to commencing in a high noise area. - safeguard the hearing of the employee. The employee must spend 14 hours without exposure to workplace noise before being tested.
Engineering Controls Sound barriers should be placed between the noise source and employees. Administrative Controls Limiting the amount of time a worker spends in a high noise area or relocating work areas away from noise. Hearing Protection Personal hearing protection devices come in many forms and they decrease the exposure to noise. One of the above must be in place in an area of 85 dBA.
The amount of time the employee is exposed to high noise levels without regard for hearing protection should be decreased to less than 8 hours. The number of employees working in the noisy area should be limited to the absolute minimum. A roster system could be arranged where employees are not working in the same areas every day.
The regulations are aimed at protecting workers from the risks to their hearing caused by noise and at preventing hearing loss and deafness. They apply to all work places and all workers. Regulation requirements: (i) Identify the noise problem (ii) Assessing noise levels (iii) Keeping a record (iv) Action taken to reduce the risk from noise (a) general (b) when levels are too high. Penalties for a breach of regulations. Any person who contravenes any of the regulations is guilty of an offence and on conviction is liable to a fine not exceeding £1,000. Both company and individual may be prosecuted.
MS Clip Art
(Photo courtesy of OSHA.gov)
Illustrations: OSHA
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.
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.
Photo: Oregon OSHA
Noise means different things to different people (e.g. rock music and elderly parents). Noise can get in the way of sounds we would rather hear. We are exposed to noise at work, home and in traffic. If it gets loud enough it can cause problems. Hearing is one of lifes important gifts (babies crying, etc.) How it effects us depends on age, health, frequency of sound, length of exposure. (i) Continuous - music, grinders, engineers running (ii) Impulse - pneumatic tools, punch press, gun shots - more damaging. Difference - length of time over which the sound occurs, both can create noise at damaging levels. Side effect of noise: (i) Behavioral effects - annoyance and agitation (ii) Stress induced problems - high blood pressure and stomach ulcers (iii) Fatigue and impaired concentration causes an increase in errors (iv) Speech interference - poor communication and safety risks causing accidents (v) Reduction in productivity level - distracting (vi) Loss of hearing
Hearing is one of your basic human senses and must be protected. Unwanted or unpleasant levels of sounds is called noise and can damage your ability to hear. Potentially damaging noise can be found both on and off the job and you must protect yourself in both situations. Protect you hearing, once its gone it cannot be replaced.