noise pollution glenn abdelnor

8/14/2019 Noise pollution Glenn Abdelnor

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Noise Control Practices inthe Workplace

STEP Network Meeting

August 17, 2005


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Noise

Before We Discuss Noise

Control Lets Review SomeNoise Concepts


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Noise Measurements

Noise Levels are Expressed as

Decibels (dB)


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DEVICE dBA

Computer 37 - 45Refrigerator 40 - 43

Cloths Dryer 56 58

Garbage Disposal 76 - 83Vacuum Cleaner 84 - 89

Lawn Mower 88 - 94

Weed Whacker 94 - 96

Leaf Blower 95 - 105

Circular Saw 100 - 104


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1+1+1 Does Not Equal to3

The Decibel is a Logarithmic

Unit of Measure So We CantSimply Add Numbers


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Keep the Calculator in theDesk

We Can Use a Few Rules of

Thumb


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Shake, Rattle, and Roll

How We Perceive Noise


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High Frequency Noise

Power Tools, Saws, Grinders Other High RPM Equipment

Sudden Release of Pressure


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Low Frequency Noise

Low frequency Noises Can

Travel Around and ThroughObjects and Are Harder toShield and Absorb


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Harmful Effects

Harmful Effects of Noise AreRelated to the Noise Dose


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Is the Noise Harmful?

Ask Yourself:

How Loud, How Long, HowMany Times?


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Noise Dose is a

Combination

Intensity of Noise (how loud)

Duration of Noise Exposure (how long) Frequency (how many times during the

day are they exposed to such a noise)


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Noise Regulated as an 8 hour Time

Weighted Average (TWA) An 8 hr TWA of 90 dBA is designated

as a Noise Dose of 100%


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First Rule of Thumb

5 dB Halving Rule


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Over an 8 Hour TWA

Period

95 dBA over 4 Hour TWA Period



110 dBA over Hour TWA Period


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Duration (How Long)

The 5 dB Rule Can Be Useful

in Estimating Whether a Noiseor an Activity Would Result inEmployees Being Exposed to

Noise In Excess of the PEL


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Example An Employee Must Enter a Pump Room and

Conduct Preventative MaintenanceThe Small Portable Sound Level Meter Reads

105 dBA Inside the Pump Room How Long Could the Employee Stay in the

Pump Room Without Exceeding the DoseEquivalent Noise Exposure of 90 dBA over

an 8 hour TWA?


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Answer

Employee Noise Exposure for

1 Hour at 105 dBA Would Bethe Dose Equivalent Exposureof 90 dBA for an 8 Hr TWA

.


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Administrative Controls

Likewise, Limiting Employee

Exposure Time to Noise CanHelp Reduce the Possibility ofHearing Loss


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Watch Where YoureStanding

Employee Noise Exposures

Often Depend on How CloseThey Are to the Noise Source


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Distance

Noise Quickly Decreases as

You Move Away from theNoise Source


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6 dB Double Distance Rule

Noise Will Decrease 6 dBEach Time You Double the

Distance(free field, point source only)


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6 dB Rule Would Not Apply


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6 dB Rule Would Not Apply


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If a Tree Falls in theWoods

Moving the Employee or the

Noise Source DoesntEliminate the Loud Noise, itJust Reduces the Employee

Exposure to it!


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Think Out Loud

In Moving the Source, Have

You Created a Problem forSomeone Else?


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Isolation Methods

Can You Isolate the Noise

Source or The Employee Fromthe Noise Source?


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Enclosing the Employee

The Cab of Heavy Earth

Moving Equipment is a GoodExample. They are Insulated(and Air Conditioned).


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Isolation Methods

Install Barriers Between theEmployee and Noise Source

Enclose the Noise Source

Enclose the Employee


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Think Out LoudBe Careful When Constructing

Barriers or Enclosures. Noise May

be Deflected Backwards Off theBarriers or the Walls of the

Enclosure Which Can Increase the

Noise Intensity on the NoiseSource Side. Employees who Must

Service Equipment or Conduct

Work in Those Areas Ma Now be


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in Enclosure Creates

Louder Noise


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Noise Absorbing Material

The Good, The Bad, and The

Ugly


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The Good

Noise is Absorbed, Its Gone, ItWouldnt Bother Anyone Anymore

High Frequency Noises are Easierto Absorb


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The Bad

Some Types Can be Fragile Some Types Can be Hard to Clean

Some Can Be Expensive


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Transmitting Vibration

Noise and Vibration Can Be

Transmitted to Other SurfacesWhich Then also TransmitsNoise


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Generated by Vibration

Sources Dampners, Springs, or Isolation Material

under Motors and Large Equipment Ensure Plates, Covers, Doors, and Access

Panels are Securely Attached Bent or Warped Shafts on Motors and

Fans Can Create Vibration

Bad Bearings, Flywheels, Pulleys, FanBlades, and Belts


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By the Way

Poor Maintenance Can Be aMajor Source of Noise

Exposure and One Which isOften Consider Economically

Feasible.


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Noise Created By EscapingAir

The Sudden Release of AirCan Be a Significant Source of

Noise Exposure


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Controlling Noise Created

By Released Air

Muffler systems on Pneumatic

Equipment When Available Reduce Air Pressure if Possible

Discourage the Use of Compressed

Air for Cleaning Purposes Only Use Approved Nozzles When

Compressed Air is Used for Cleaning


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You May Not Be The

FirstPerson To Ask

Contact the Manufacturer ofthe Equipment and Request

Assistance in Determining Waysto Help Decrease Noise Output

of the Machines


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Hearing Protection

Hearing Protection does not ReduceEmployee Noise Exposure, It Reduces

the Potential Harm Which CouldOtherwise Result in an Unprotected

Employee


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Hearing Protectors

Like Respirators, They areOnly Effective if Used Properly


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Attenuation of Ear Plugs

The Greater the NRR Numberthe Greater the Protection


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Hearing Protectors

Ear Plugs and Other Types ofHearing Protection HaveLimitations on How Much

Protection They Can Provide


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noise pollution glenn abdelnor

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