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munna_bhosale@yahoo.co.in
34

Dear All, Please find attache ppt on noise.. Regards,
From Czech Republic, Mlada Boleslav
Attached Files (Download Requires Membership)
File Type: ppt Noise.ppt (117.0 KB, 1800 views)

Kesava Pillai
252

Dear Munna,

I appreciate your attempt in producing the ppt !

How ever if for once you sit back and ask the following types of questions you will realize that something is missing from your presentation. While we make a safety/health presentation the one who goes through it should not leave it with related issues unanswered. If you are in the profession kindly take it in good spirit; incorporate the answers to the questions below and more if you have, which will give you an excellent professional presentation.

Noise is unwanted sound then what is sound?

What are the characteristics of noise?

How people differentiate between sound and noise?

What is the anatomy of ear ?

How we hear or what is the hearing mechanism?

How noise induced hearing loss takes place ?

What is dB ?

Noise level is taken only in dBA or more up to dBZ ?

What is the instrument used for measuring noise ?

Is there more than one type of measurement for noise measurement?

What is audiometry ?

How to select ear protection ?

What are the differences between ear plugs, canal caps and Muff type ear defenders?

Is fit test necessary for ear defenders?

How to maintain the ear defenders?

Regards,

Kesava Pillai

From India, Kollam
Makaniya Bashir
3

dear munna, its very useful for everyone to how can save health ....! keep it ip...! Bashir...
From India, Pune
abhaygirish
49

@Mr. Munna ,

Nice ppt. Thanx

Pls go thru the questions asked by Kesava sir and try to revert back with adequate answers. He gave us this opportunity for become perfect in this hazard type and I hope he will guide us in all such area one by one.

Regards,
Abhay

From India, Mumbai
raghuvaran chakkaravarthy
497

Dear kesav sir,

I was add my inputs on this thread please review and advice me. . .

Noise is unwanted sound then what is sound?

Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.

What are the characteristics of noise?

There are two important characteristics of sound or noise - frequency and loudness.



How people differentiate between sound and noise?

sound is a kind of vibration which travel through air, water, and are sensed by the ear. a thing that can be heard. This is from music, speech, and others like films dialogs etc., one thing in this matter is that we can increase the volume of sound or decrease as per our taste if it is from radio, television, computers and man operative machines.whereas,a noise is a sound from one and more at a time which can not be heard clearly and only mixed sounds will be heard. you can not increase or decrease the noise. If a meeting, there will be noise among the people talking each other besides the speaker going on talking. in a shandy, there we can hear the noise since several persons are on buying and selling. in an office one is talking on mobile, phone ringing another side, ring tones in some person's hands, loud conversations with one and another etc., this is called noise. Even, a music in public place with loud voice will also be a noise in general, a sound is a vibration from a particular machine, place or material which can be heard clearly whereas a noise a mixed vibrations that will come to us from all directions. A sound can be clear and can be able to hear, whereas a noise will not be clear and can not be heard.

How we hear or what is the hearing mechanism?

Sound waves hit the ear drum ("tympanic membrane"), which transmits the impulse through the three bones of the middle ear, which transmit the sound wave impulses to the inner ear, which "transduces" the signal into a sort of electrical signal the brain can interpret.

What is dB ?

The decibel ( dB) is used to measure sound level, but it is also widely used in electronics, signals and communication. The dB is a logarithmic unit used to describe a ratio. The ratio may be power, sound pressure, voltage or intensity or several other things.

What is the instrument used for measuring noise ?

decibel meter

What is audiometry ?

Audiometry is the testing of a person's ability to hear various sound frequencies. The test is performed with the use of electronic equipment called an audiometer.

How to select ear protection ?

Please see the attached . . .

Please review this thanks in advance. . .

Dear munna,

Thanks for your noice/sound related PPT. . .

Thanks & Besafe

Raghu

From United States, Fpo
Attached Files (Download Requires Membership)
File Type: pdf criteria_hearing_protection_selection.pdf (54.9 KB, 226 views)

abhaygirish
49

Additional Inputs ( In Blue Colour) From My side after discussing with my S.O.:

I was add my inputs on this thread please review and advice me. . .

Noise is unwanted sound then what is sound?
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.

What are the characteristics of noise?
There are two important characteristics of sound or noise - frequency and loudness.
FREQUENCY- perceived as pitch , INTENSITY- perceived as loudness , NATURE- steady-state vs. impulse/impact ,DURATION- length of time exposed

How people differentiate between sound and noise?
sound is a kind of vibration which travel through air, water, and are sensed by the ear. a thing that can be heard. This is from music, speech, and others like films dialogs etc., one thing in this matter is that we can increase the volume of sound or decrease as per our taste if it is from radio, television, computers and man operative machines.whereas,a noise is a sound from one and more at a time which can not be heard clearly and only mixed sounds will be heard. you can not increase or decrease the noise. If a meeting, there will be noise among the people talking each other besides the speaker going on talking. in a shandy, there we can hear the noise since several persons are on buying and selling. in an office one is talking on mobile, phone ringing another side, ring tones in some person's hands, loud conversations with one and another etc., this is called noise. Even, a music in public place with loud voice will also be a noise in general, a sound is a vibration from a particular machine, place or material which can be heard clearly whereas a noise a mixed vibrations that will come to us from all directions. A sound can be clear and can be able to hear, whereas a noise will not be clear and can not be heard.


If you have to raise your voice to be heard by someone standing within 3 foot (arm’s length) then the level is most likely above the hazardous noise level

How we hear or what is the hearing mechanism?
Sound waves hit the ear drum ("tympanic membrane"), which transmits the impulse through the three bones of the middle ear, which transmit the sound wave impulses to the inner ear, which "transduces" the signal into a sort of electrical signal the brain can interpret.

How noise induced hearing loss takes place ?

NIHL : Initially, exposure to noise causes a loss of sensitivity to high frequency (high pitch) sound. Continued exposure results in damage to mid frequency region as well. One can experience progressive high frequency hearing loss and not be aware of it until it becomes severe .and how it happens :
ACOUSTIC TRAUMA – ONE TIME EXPOSURE TO LOUD SOUND
OR DAILY EXPOSURES TO MODERATELY LOUD SOUNDS

Noise level is taken only in dBA or more up to dBZ ?

About dBZ - ??????
for impulse/impact noise sources - heard about dBP


What is dB ?
The decibel ( dB) is used to measure sound level, but it is also widely used in electronics, signals and communication. The dB is a logarithmic unit used to describe a ratio. The ratio may be power, sound pressure, voltage or intensity or several other things.

What is the instrument used for measuring noise ?
decibel meter

What is audiometry ?

Audiometry is the testing of a person's ability to hear various sound frequencies. The test is performed with the use of electronic equipment called an audiometer.

How to maintain the ear defenders?
Keep clean with mild soap and water and dry before using
Replace when material hardens/cracks or does not clean
Check for cracks on earphone seals, headband tension and replace as needed

How to select ear protection ?

Please see the attached . . .

Please review this thanks in advance. . .

Raghuji!!!!

Thanks for your inputs

Regards,
Abhay

From India, Mumbai
raghuvaran chakkaravarthy
497

Dear abhay, Good work. . .Thanks for your input on this matter.Seniors Please come forward put on your inputs and advice us. . . Thanks in advance. . . Thanks & Besafe Raghu
From United States, Fpo
Kesava Pillai
252

Dear friends,

Reghu' and Abhay both your attempts are very well appreciated. Almost all the answers are reasonably good.

I am posting the answers but partly. In subsequent weeks I will post the remaining also.

1. A vibrating body pushes on molecules, creating a series of pressure waves that radiate out from the source of the vibration and we call it sound.. Sound can be wanted or unwanted at times. Physically sound and noise are same. It depends up on the receiver’s mood. However in terms of occupational health, noise can be defined as any sound that is intense enough to damage hearing.

Thus a sound wave is a series of these compressions and rarefactions traveling through a substance. The individual molecules do not travel; rather, they vibrate rhythmically back and forth. Sound, in non-technical terms, is variation in air pressures, above and below atmospheric

2. Intensity or loudness and frequency or pitch.

3. With one’s changing mood the same sweet sound of music can be noise at a different occasion.

4. Outer ear, ear drum, the three smallest bones in the body called anvil, hammer and stirrup and the cochlea a tubular section containing hair cells. Photographs and pictures are available in plenty.

5. Your outer ear collects sound waves and channels them down the ear canal to a thin, tight piece of skin called the Tympanic membrane (ear drum) The eardrum vibrates in response to these pressure waves and pushes on the small bones of your middle ear. These bones act like a set of levers, transferring their mechanical motion to a fluid-filled structure in the inner ear, called the: cochlea. In the cochlea, cells with tiny sensing hairs transform the fluid movement into electrical signals. These signals travel along the auditory nerve to your brain. Once in the brain, the nerve signals are decoded and processed into what we recognize as sound.

6. Due to excessive noise the hair cells gets destroyed and that particular frequency sound connected with the destroyed hair cells will not be received any more.

7. The unit of sound measurement is the “decibel” (abbreviated dB), which is 1/10 of a bel, named in honor of Alexander graham bell. The higher the number of decibels, the louder the sound. One decibel represents the weakest sound audible. A whisper would read about 10 decibels on the sound level meter.

8. Measurements are in dBA, dBB or dBC. However for noise conservation we are quite particular about the speech range of frequencies. dBA is connected with this filtering out other frequencies. Thus we prefer dBA for measurement in connection with noise conservation.

9. Noise is measured using a sound level meter.

10. We require frequency analyzer too. Intensity alone is not sufficient. Intensity should be checked along with octave band analyzer (frequency).

Regards,

Kesava Pillai

From India, Kollam
Kesava Pillai
252

Dear Friends,

Here are the remaining points

11. An audiometric examination tests -hearing acuity. The audiometric testing procedure tests one’s hearing threshold at a range of different frequencies. The hearing threshold is the lowest level at which one is able to detect the test tone at each frequency and is determined by his response. Tests are performed in both ears.

12. Apart from all other general consideration for selecting any PPE the manufacturer has to give the NRR (noise reduction ratio) of the ear defender. NRR will never be correct because of Leaks in the seal, Vibration and Improper insertion. NRR - Application is as noted below:

a. Earmuffs - Subtract 25% from the manufacturer's labeled NRR

b. Formable earplugs - Subtract 50% from the manufacturer's labeled NRR

c. All other earplugs - Subtract 70% from the manufacturers labeled NRR

I am sure that most safety officers may not have even heard about this. However it is a very serious point to be strictly followed.

13. Ear plug and canal caps are inserted into the ear. Ear plugs are squeezed into the ear canal and expands to seal. Canal caps are rigid and pushed in seal and will not reshape inside and hence not much preferred. Ear Muffs are to seal at the periphery of the ear in total which will give a better seal if selected properly.

14. Ear defenders require fit test without which noise reduction as necessary can not be assured.

15. Disposable type – throw them off after day’s use. Others clean and disinfect to store in hygienic condition. Replace defective ones. Check every time before using. Never use ear defenders used by others.

Regards,

Kesava Pillai.

From India, Kollam
boss2966
1166

Dear Kesav, Raghu and Abhay
It is nice to see such a informative and educative healthy discussion and knowledge sharing in this worthy forum.
Great sharing.
Keep on sharing
With warm regards.
S. Bhaskar
9099024667

From India, Kumbakonam
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