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

Occupational noise

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Page 1: Occupational noise

OCCUPATIONAL NOISE

STACY ARVINNAGROUP 34TH YEAR 1ST SEM11 JANUARY 2011HYGIENE SUBJECT

Page 2: Occupational noise

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.

Page 3: Occupational noise

AN EAR’S ANATOMYHOW WE HEAR?

Ear Outer ear -

directs sound waves

Middle ear - eardrum - hammer, anvil, stirrup

Inner ear - organ of corti, cochlea

Page 4: Occupational noise

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.

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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).

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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.

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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

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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

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OCCUPATIONAL HEARING LOSS

Noise-Induced Hearing Loss or Noise-Induced Permanent Threshold Shift (NIPTS)Permanent sensor neural conditionCannot be treated or corrected medically Initially effects high frequencies

Industrial trough Speech recognition

Progresses to lower frequencies

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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.

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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

NON-AUDITORY EFFECTS OF NOISE

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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

Page 14: Occupational noise

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)

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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

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NOISE MEASURING EQUIPMENT

Octave band analyzer

Diagnostic tool to help find appropriate engineering controls to reduce noise levels

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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.

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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

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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)

Page 20: Occupational noise

HEARING CONSERVATION

Bulldozer: 85dBA

Quite Room: 30 dBA

Normal Conversation: 50 dBA

Normal City Noises: 65 dBA

Artillery/Good Rock Band: 120 dBA

Page 21: Occupational noise

HEARING PROTECTION

Three ways to protect your hearing:Engineering controlsAdministrative controlsPersonal Protective Devices

Page 22: Occupational noise

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

ENGINEERING CONTROLS

Page 23: Occupational noise

ADMINISTRATIVE CONTROLS

Decreasing the exposure time

Limiting the number of personnel

exposed

Arranging a work roster system

Page 24: Occupational noise

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.

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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

Page 26: Occupational noise

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.

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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.

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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

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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

Page 30: Occupational noise

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

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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.

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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

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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

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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)

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HEARING PROTECTORS

Provided at no cost to the employee

Selected from a variety of types and brands

Properly fitted

Replaced as necessary

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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.

“EAR PLUGS”

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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.

“EAR MUFFS”

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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

Page 39: Occupational noise

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

Page 40: Occupational noise

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