osha hearing conservation program short

7/27/2019 OSHA Hearing Conservation Program SHORT

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10/1/99 Created By: C. Miterko 2

29 CFR 1910.95


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What is Sound? Sound is what we hear andis produced by vibratingobjects and reaches thelisteners ears as waves in theair or other media.

When an object vibrates itcauses slight changes in airpressure. These air pressurechanges travel as wavesthrough the air and producesound.

. .


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.


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What is Noise?

Hertz (Hz)


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Frequency

Humans can typically hearbetween 20 - 20,000 Hz 20

20000 3000 0.00002 Pa


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dB .

:dB = 20 log {sound pressure/Ref. Pressure (0.00002

Pa)}

Sound pressure level in very quite room where thesound pressure is 0.002 Pa is:

Lp (dB) = 20 log (0.002/0.00002) = 20 log 100 = 40 dB


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Common Sounds0 dB Threshold of Hearing

30 dB Soft Whisper

40 dB Quiet Office

60 dB Conversational Speech

80 dB Very noisy restaurant

90 dB Subway

110 dB Woodworking

120 dB Hydraulic press

140 dB Threshold of Pain

Jet plane

180 dB Rocket


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How do we Hear?

1- 2- -3 -4


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Example

In the field, we determined the loudness of

two compressors right next to each other

How loud is this area?

Do we add?Do we add and take the average?

89 dB 87 dB


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Neither, because it is a log scale

We use the following chart

82 dB + 83 dB = 86 dB

87 dB + 89 dB = 91 dB

Difference in dBValues

Add to HigherLevel

0-1 dB 3 dB

2-3 dB 2 dB

4-9 dB 1 dB

10 dB or more 0 dB


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How does the Safety Person

determine noise levelsSound level meter

Determine theloudness (dB) ofnoise at any given

moment

Personal Dosimeters

Worn by employees

Measures the average

loudness in an 8 hourwork shift

8hr. TWA (TimeWeighted Average)

8


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What does OSHA say?

At 85 dB (8hr. TWA) (Action level) (885 ) Train employees

Make hearing protection available

Sample for noise levels

Do hearing tests

Notify employees of results


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Hearing Conservation Program


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Hearing Conservation Program

Monitoring:

Employers should monitor noise exposure

levels to identify employees who are

exposed to noise levels at or above 85

dBA averaged over 8 working hours, or

an 8-hour time-weighted average (TWA).

Noise level meters & Noise Dosemeter are

used after being calibrated.


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When the daily noise exposure has two or morenoise exposures at different levels, their

combined values should be considered. (Use thefollowing formula)

F(e) = (T(1) divided by L(1) + (T(2) divided byL(2(( + )T)n( divided by L)n((

F(e)= The equivalent noise exposure factorT= The period of noise exposure at any essentially

constant level.

L= The duration of the permissible noise

exposure at the constant level.If the value of F(e) exceeds unity (the value 1), the

exposure exceeds PEL.


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Example:

110 dbA 0.25 hours

100 dbA 0.5 hours

90 dbA 1.5 Hours

F(e) = (0.25/0.5) +

(0.5/2)+(1.5/8)

F(e)=0.5+0.25+0.1888

F(e) = 0.938

Since F(e) does not exceed

unity (1), the exposure

limit is within

permissible limits

Duration Per

Day, Hours

Sound Level

dBA

8 90

6 92

4 95

3 97

2 100

1 102

1 105

107

110

115


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Audiometric Testing

Should the noise level monitoring determine

that employees are being subjected to levels

equaling or exceeding a TWA of 85 dBA, the

next step is to establish an audiometric testingprogram for those exposed at no cost to the

employee.

The important elements of an audiometric

program include: Baseline audiograms, Annualaudiograms, Control measures, Training, and

follow-up procedures.


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Baseline Audiograms

It is the reference audiogramagainst which future audiogramsare compared.

Must be provided within 6months of an employees firstexposure at or above 8-hour TWAof 85 dBA. (Control measuresshould be taken)

Baseline Audiogram must bepreceded by 14 hours withoutexposure to workplace noise.


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Annual Audiograms

After baseline audiogram has been taken,

each employee exposed to noise levels at

the 85 dBA or above shall have annual

examination.

Annual audiogram must be conducted

within 1 year of the baseline.

Compared with baseline audiograms

results.


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Continued

To determine whether an employee hasexperienced any recordable hearing loss.

The hearing loss is reffered to in the

OSHA standard as :Standard ThresholdShift (STS).

OSHA defines STS as a change in

hearing threshold relative to the baselineaudiogram of an average of 10 dB ormore at 2000, 3000, and 4000, Hz ineither ear.


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Example Baseline Audiogram

125 250 500 1K 2K 3K 4K 6K 8K

10

0

10

20

30

40

50

Baseline Audiogram

(The initial audiogram

taken by worker whenfirst employed.)


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Annual Audiogram (Showing STS)

125 250 500 1K 2K 3K 4K 6K 8K

10

0

10

20

30

40

50

BASELINE

ANNUAL

169

816 + 9 + 8 = 3333 / 3 = 11

Reportable Loss? NO

STS ? YES


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Control

The standard states that if the 90 dB PEL

is being exceeded, feasible

administrative or engineering controls

shall be utilized.

If fails, PPE shall be provided and used

to reduce sound levels.

Administrative Controls


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Administrative Controls

* Are defined as, Methods of controlling

employee exposures by job rotation,

work assignment, or time periods away

from the hazards.


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Engineering Control

Are defined as Methods of controlling

employee exposures by modifying the

source or reducing the quantity of

contaminants released into the workroomenvironment.

Example: installing noiseabsorbing

acoustical foam or baffles to capture anddeaden reverberating noise.


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Hearing Protectors

Hearing protectors shall be made

available and shall be worn by all

employees exposed to an 8-hour TWA of

85 dBA or greaters.

Types of hearing protectors:

Ear muffs

Ear plugs

Ear canal


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Earmuffs Earplugs Canal Caps

Examples of Hearing Protectors


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Hearing ProtectionNRR- Noise reduction rating

Express - 25 NRR

Classic - 29 NRR

Max Lite - 30 NRR

DO NOT Subtract the NRR from the

noise level

WRONG (109 dB - 25 NRR = 84 dB)

You must use the Safety Factor


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Safety Factor

OSHA says the hearing protection isdesigned to reduce the noise by theNRR, but that is unlikely to happendue to :

Leaks in the sealVibration

Improper insertion

(NRR - 7)


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Example of NRR Protection

The noise at a large compressor is

109 dB

You are wearing the Express plugs with

anNRR of 25

Do you have enough protection to placeyou below 90 dB level?


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Training - Recordkeeping

Employees training is very important. All

employees exposed to noise at a TWA of

85 dBA or greater shall participate in a

hearing conservation training program.

An accurate records shall maintained of

all employee exposure measurements.

osha hearing conservation program short

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