How Do You Handle Noise Issues in the Workplace? Let's Discuss Solutions

Noise Presentation

Please find attached a PowerPoint presentation on noise.

Regards,

Dear Munna, I appreciate your attempt in producing the PPT! However, if for once you sit back and ask the following types of questions, you will realize that something is missing from your presentation. When we create a safety/health presentation, the individual who reviews it should not be left with unanswered related issues. If you are in the profession, kindly take this in good spirit; incorporate the answers to the questions below and more if you have them, which will enhance your professional presentation.

- What is sound if noise is unwanted sound?
- What are the characteristics of noise?
- How do people differentiate between sound and noise?
- What is the anatomy of the ear?
- How do we hear, or what is the hearing mechanism?
- How does noise-induced hearing loss occur?
- What is dB?
- Is noise level measured only in dBA or up to dBZ?
- What instrument is used for measuring noise?
- Are there multiple types of measurement for noise?
- What is audiometry?
- How do you select ear protection?
- What are the differences between earplugs, canal caps, and muff-type ear defenders?
- Is a fit test necessary for ear defenders?
- How do you maintain the ear defenders?

Regards, Kesava Pillai

@Mr. Munna,

Nice ppt. Thanks. Please go through the questions asked by Kesava sir and try to revert back with adequate answers. He gave us this opportunity to become perfect in this hazard type, and I hope he will guide us in all such areas one by one.

Regards,
Abhay

Noise Presentation

I have added my inputs on this thread. Please review and advise me.

What is Sound?

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. It is 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.

Characteristics of Noise

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

Differentiating Between Sound and Noise

Sound is a kind of vibration that travels through air and water and is sensed by the ear. It is something that can be heard, such as music, speech, and other sounds like film dialogues. We can adjust the volume of sound as per our preference, but noise is a combination of sounds that cannot be clearly heard or individually adjusted. For example, in a meeting, multiple people talking can create noise. In a market, the various sounds of buying and selling merge into noise. A clear sound can be heard distinctly from a particular source, while noise is a mixture of indistinct sounds from various directions.

Hearing Mechanism

Sound waves hit the eardrum (tympanic membrane), which transmits the impulse through the three bones of the middle ear to the inner ear. The inner ear transduces the signal into an electrical signal that the brain can interpret.

What is dB?

The decibel (dB) is used to measure sound levels and is also widely used in electronics, signals, and communication. It is a logarithmic unit that describes a ratio, which may involve power, sound pressure, voltage, intensity, or other factors.

Instrument for Measuring Noise

A decibel meter.

What is Audiometry?

Audiometry is the testing of a person's ability to hear various sound frequencies using electronic equipment called an audiometer.

Selecting Ear Protection

Please see the attached...

Thank you for your noise/sound-related PPT.

Thanks & Be safe,

Raghu

Please review this. Thanks in advance.

Additional Inputs (In Blue Colour) From My Side After Discussing With My S.O.:
I have added my inputs to this thread. Please review and advise 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 Do People Differentiate Between Sound and Noise?
Sound is a kind of vibration that travels through air and water and is sensed by the ear. It is something that can be heard, such as music, speech, and other sounds like film dialogues. One thing to note is that we can increase or decrease the volume of sound to our taste if it is from a radio, television, computer, or man-operated machine. In contrast, noise is a sound from one or more sources at a time that cannot be heard clearly, resulting in mixed sounds. You cannot increase or decrease the noise. For example, in a meeting, there will be noise among people talking to each other besides the speaker. In a marketplace, we can hear noise since several people are buying and selling. In an office, one person might be talking on a mobile phone, while another phone rings, and loud conversations occur simultaneously. This is called noise. Even music played loudly in a public place can be considered noise. Generally, sound is a vibration from a particular machine, place, or material that can be heard clearly, whereas noise is mixed vibrations coming from all directions. A sound can be clear and audible, whereas noise is not clear and cannot be heard distinctly.

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

How Do We Hear, or What is the Hearing Mechanism?
Sound waves hit the eardrum ("tympanic membrane"), which transmits the impulse through the three bones of the middle ear. These bones transmit the sound wave impulses to the inner ear, which "transduces" the signal into an electrical signal the brain can interpret.

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

Is Noise Level 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, 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

Good work. Thanks for your input on this matter. Seniors, please come forward to share your insights and advice with us. Thanks in advance.

Regards,
Raghu

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. Understanding Sound and Noise

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 the same. It depends 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 a variation in air pressures, above and below atmospheric.

2. Key Characteristics of Sound

- Intensity or loudness and frequency or pitch.

3. Perception of Sound

With one's changing mood, the same sweet sound of music can be noise on a different occasion.

4. Anatomy of Hearing

Outer ear, eardrum, 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. How We Hear

Your outer ear collects sound waves and channels them down the ear canal to a thin, tight piece of skin called the Tympanic membrane (eardrum). 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. Impact of Excessive Noise

Due to excessive noise, the hair cells get destroyed, and that particular frequency sound connected with the destroyed hair cells will not be received anymore.

7. Sound Measurement Units

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. Noise Measurement Standards

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. Tools for Measuring Noise

Noise is measured using a sound level meter.

10. Need for Frequency Analysis

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

Regards, Kesava Pillai

Dear Friends,

Here are the remaining points:

11. Audiometric Examination

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 their response. Tests are performed in both ears.

12. Noise Reduction Ratio (NRR) Considerations

Apart from all other general considerations for selecting any PPE, the manufacturer has to provide 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:
- Earmuffs: Subtract 25% from the manufacturer's labeled NRR.
- Formable earplugs: Subtract 50% from the manufacturer's labeled NRR.
- All other earplugs: Subtract 70% from the manufacturer's 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. Types of Ear Protection Devices

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

14. Fit Testing for Ear Defenders

Ear defenders require a fit test without which noise reduction as necessary cannot be assured.

15. Maintenance and Usage of Ear Defenders

Disposable type – throw them off after a day's use. Others should be cleaned and disinfected to store in a hygienic condition. Replace defective ones. Check every time before using. Never use ear defenders used by others.

Regards,

Kesava Pillai.

Dear all, thank you for the great discussion, but I apologize for being late. I would also like to add something:

- Sound has both frequency and intensity.
- Frequency or pitch is the number of sound vibrations per second.
- The higher the frequency, the higher the pitch.
- Intensity refers to the degree of strength or energy.
- Noise-Induced Hearing Loss: i) Frequency, ii) Intensity.
- Intensity over 130 dB is painful and can damage hearing.
- Critical level: 85-120 dB is not painful but can damage ears.

Consequences:

1. Difficulty in hearing background noise.
2. Specific hearing limitations; loss occurs in high frequencies.

OHSAS Requirements for Training Program:

1. Employee Training: i) Effects of noise, ii) Hearing protection, iii) Audiometric test, iv) Measuring noise.
2. Exposure monitoring.
3. Audiometric test.
4. Employee follow-up.
5. Record keeping.
6. Noise control.
7. Hearing Protection Devices.

To Measure Noise:

- Dosimeter: Body-worn instrument that measures and stores sound over time and can be read later.
- Engineering Surveys: Require sophisticated acoustical equipment that registers dB level, frequency, and intensity of noise from machinery.
- Audiometric Test: Within 6 months of first exposure to critical level. It measures the softest sound you can hear at each test frequency.

Standard Threshold Shift:

Significant but decreases in the ability to hear at frequencies first affected by noise exposure. Notify within 21 days.

Some more information will be added soon... Lights are gone and I need to log out.

Regards

Dear all, Here is some more information that was left out in the above post.

Point of Control of Noise

- At the source: Lubricating moving/rotating parts, tightening vibrating surfaces, replacing old parts.
- By routes traveled: Using sound-absorbing materials such as cushioning, padding using rubber parts.
- Individual exposure: Cover metal walls with insulation, make sound barriers.

Hearing Protection

- Ear plug
- Ear muff
- Banded Protection: Inserted in the ear canal to block noise.

Noise Reduction Rating (NRR)

Hearing protection devices are rated for their effectiveness in decreasing noise. This is called NRR. NRR is compared to the work environment's monitored noise level. To calculate adequate protection: Divide NRR in half.

EAR PLUG

(Reducing rating from 21-33 dB)

- Formable: Fine glass fiber, wax-filled cotton, expandable plastic, or foam. One-time use, decreases sound by expanding to seal the ear canal opening.
- Custom molded: Designed for individuals, silicone, rubber, plastic molding.
- Pre-molded: Silicone, rubber, plastic; vary in size, shape, fits to seal the ear.

Advantages of Earplug

Inexpensive, portable, comfortable, do not interfere with headgear, do not restrict head movements.

Disadvantages

Difficult to fit, dirt into the ear, lost, fall out, protection level varies.

Banded Plugs

Soft form, rubber, soft plastic, plastic cover sponge. Lowest NRR - 17 to 25 dB reduction may be appropriate as low as 90 dB, not always versatile with headgear.

Form Earplugs

Highest NRR. Protection depends on how well it fits in the ear.

Regards, Hansa

Dear Hansa, Thanks for all your inputs, especially on this Noise/Sound thread.

Dear Kesav, Hansa, Abhay, Thanks a lot for sharing valuable information regarding noise/sound. This thread has been particularly helpful in expanding my knowledge about noise/sound.

Dear Members,

If anybody has questions, please come forward; otherwise, we will close this thread.
Regards

Dear Seniors, I am new to this site, and it is a really great platform for learning for fresh candidates.

1) Is any special training required for noise monitoring?
2) Who is the responsible person for monitoring noise (Safety Officer or Environmental Personnel)?

It was a really great discussion on noise, and I would like to know the answers to these queries. Thanks in advance for your inputs.

Regards,
Ramchandra

Dear Ram Chandra,

OHSAS Requirements for Training Program

1. Employee Training:
- Effects of noise
- Hearing protection
- Audiometric test
- Measuring noise

2. Exposure monitoring
3. Audiometric test
4. Employee follow-up
5. Record-keeping
6. Noise control
7. Hearing Protection Devices

To Measure Noise

- Dosimeter: A body-worn instrument that measures and stores sound over time, which can be read later.
- Engineering Surveys: Require sophisticated acoustical equipment that registers dB level, frequency, and intensity of noise from machinery.

Audiometric Test

To be conducted within 6 months of the first exposure to critical levels. It measures the softest sound you can hear at each test frequency.

Noise monitoring by Dosimeter is carried out by the environmental department in our plant. Audiometric tests are conducted by doctors, and Engineering Surveys can be performed by the Safety Department.

Seniors, I am looking forward to hearing your views as well.

Regards,
Hansa Vyas

Thank you very much for your quick response. I would like to add some points from my side.

OSHA Training Requirement 1910.95(i)(4):

- The employer shall provide training in the use and care of all hearing protectors provided to employees.
- The employer shall institute a training program for all employees who are exposed to noise at or above an 8-hour time-weighted average of 85 decibels and shall ensure employee participation in such a program.
- The training program shall be repeated annually for each employee included in the hearing conservation program. Information provided in the training program shall be updated to be consistent with changes in protective equipment and work processes.
- The employer shall ensure that each employee is informed of the following:
- The effects of noise on hearing;
- The purpose of hearing protectors, the advantages, disadvantages, and attenuation of various types, and instructions on selection, fitting, use, and care; and
- The purpose of audiometric testing and an explanation of the test procedures.

Dear seniors/all, I have one question: Is a safety trainer required to have any special certification to conduct training programs? If yes, what type of certification is required? If no, who is the competent person to conduct training (safety dept/HR dept...)?

Thanks in advance.

Dear Seniors, Thank you for your valuable inputs on this thread. Now, I would like to know how to evaluate the ear muffs or ear plugs as per international standards, if available. (Reusable or disposable? Which will be the best in the industry?) I am eagerly waiting for your inputs.

Regards, Saudagar Bhossale

The Origin and Impact of Noise

The word "noise" is derived from the Latin term 'nausea'. Noise is a type of atmospheric pollution in the form of waves. It is a shadowy public enemy that has increased in the modern age of industrialization and technological advancement.

Definitions of Noise

Many industrial psychologists and environmentalists have defined the term noise:

1. Harrell defines noise as 'an unwanted sound which increases fatigue and, under some industrial conditions, causes deafness'.
2. According to Environmental Health criteria, 'noise is considered any unwanted sound that may adversely affect the health and well-being of individuals or the population'.

What is Sound?

Physically, sound is a mechanical disturbance propagated as a wave motion in air and other elastic or mechanical media such as water or steel. Physiologically, it is an auditory sensation evoked by this physical phenomenon (fact of occurrence).

The human ear is very sensitive to sound waves of frequency 20 Hertz (unit of frequency, one cycle per second) to 2000 Hz pitch, but not all sounds are detectable by the human ear. There are two types of sounds:

1. Ultra Sound

Ultra sound is sound in which the frequency range exceeds approximately 15 Hz. It is beyond the upper limit of normal hearing, meaning it has a frequency too high to excite the sensation of hearing.

2. Intra Sound

Intra sound is sound below a frequency of about 16 Hz. It is below the lower limit of normal hearing and is commonly referred to as vibration.

With Regards,

Rohan Puthran

Evaluating Ear Muffs and Ear Plugs

I also have the same query: how to evaluate ear muffs or ear plugs according to international standards, if available? (Reusable or Disposable) Which option would be the best in the industry?

Thanks in advance for your help.

Regards,
Ramchandra