1. Noise and Hearing Conservation
Slide Show Notes
Through monitoring, we have determined that some employees are exposed to occupational noise at levels where the Occupational Safety and Health Administration (OSHA) requires us to have an effective hearing conservation plan.
Our hearing conservation plan includes monitoring, employee notification and observation of monitoring, hearing testing, hearing protection, training, and recordkeeping.
This training program will cover:
Impact of workplace noise on hearing
Advantages and disadvantages of hearing protection devices
Use, care, and fit of hearing protection devices
Need for hearing testing and what to expect
OSHA requires employers to administer an effective Hearing Conservation Program whenever employee noise exposure equals or exceeds an 8-hour time-weighted average (TWA) sound level of 85 decibels (29 CFR (c)(1)).
Hand out copies of your company’s hearing conservation plan or tell the employees where or how they can obtain copies.
Image credit: OSHA

2. Session Objectives You will be able to:
Understand the effects of noise on hearing
Identify sources of noise in your workplace
Describe the purpose of audiometric testing and be able to interpret your test results
Select, fit, and use hearing protection
Slide Show Notes
At the end of this training session you will be able to:
Understand the effects of noise on hearing.
Identify sources of noise in your workplace.
Describe the purpose of audiometric testing and be able to interpret your test results.
Select, fit, and use hearing protection
0507

3. What Is Sound?
Sound is a longitudinal pressure wave of energy with the following characteristics:
Frequency (pitch) measured in hertz (Hz)
Pressure (loudness) measured in decibels (dB)
Frequency and pressure of a sound wave with duration of exposure determine the risk of hearing loss
Slide Show Notes
Sound is a longitudinal pressure wave of energy with two important characteristics—frequency and pressure.
Frequency, also known as pitch, is measured in hertz (Hz), or cycles per second. The human ear can hear 20-20,000 Hz. Human speech is normally in the 500–2000-Hz range.
Pressure, or the loudness of the sound, is measured in decibels (dB). A whisper is approximately 10 dB and a chain saw is approximately 100 dB.
The frequency and pressure of a sound wave along with the duration of exposure determine the risk of hearing loss and other noise hazards of noise. The longer you are exposed to noise, the greater the chance of hearing damage.
0507

4. Noise Sources
Machinery, tools, and equipment emit sounds of varying loudness and in particular frequencies
Continuous or intermittent
Low-frequency equipment noise sources cause hearing loss in the speech frequencies
Slide Show Notes
There are a wide variety of sources of noise in the typical workplace, including machinery, tools, and equipment.
Noise from machinery, tools, and equipment emits sound in a particular range of frequencies at a particular sound pressure level.
Noise sources may be continuous, like most machines, or intermittent, like punch presses or jackhammers.
Low-frequency noise sources, such as that produced from vibrating equipment, are particularly hazardous because they cause hearing loss in the speech frequencies, making it difficult to understand others.
Ask trainees to name some noise sources in our facility that you are aware of.
Bring your facility noise survey to the training and discuss the major sources of noise as well as the decibel levels associated with these sources.
Consider bringing in a few noise sources to illustrate varying frequencies and sound pressure levels (e.g., whistle, air horn).
0507

5. Sound Pressure Levels of Common Noises
Noise Source Loudness
Whisper 10 dB
Conversation 65 dB
Shop tools 90 dB
Pneumatic drill 100 dB
Woodworking shop 110 dB
Abrasive blasting 115 dB
Jackhammer 130 dB
Slide Show Notes
Sound pressure level, or loudness, is measured in dB with a sound meter. Hearing damage is risked when you are exposed to more than 90 dB during an 8-hour time period without hearing protection. You will note that many common workplace noise sources exceed 90 dB. One hundred forty dB for any duration is considered very dangerous to your hearing.
Ask the employees if they can think of other activities that are loud.
0507

6. OSHA Noise Exposure Limits
90 dBA TWA for 8-hour exposure
95 dBA TWA for 4-hour exposure
100 dBA TWA for 2-hour exposure
105 dBA TWA for 1-hour exposure
Use engineering controls, administrative controls, and personal protective equipment (hearing protection) to meet standards
Slide Show Notes
The OSHA noise exposure limits vary with exposure time. As the exposure time is cut in half, the allowable sound pressure level (loudness) is increased by 5 dB. When noise exposures exceed these limits we attempt to reduce exposures below the standard using engineering and administrative controls. Hearing protection is used during this period and if these controls are not feasible.
0507

7. Indicators of High Noise Levels
Noisy conditions can make normal conversation difficult
80 dB–People have to speak very loudly
85-90 dB–People have to shout
95 dB–People have to move close together to hear each other at all
Slide Show Notes
Noisy conditions can make normal conversation difficult and can serve as a good rule of thumb to estimate noise levels.
At 80 dB people have to speak very loudly (above a normal conversation level) to be understood.
At dB people must shout in order to be understood.
At 95 dB people have to move close together to hear each other at all.
0507

8. How Is Noise Hazardous?
Noise can result in temporary or permanent hearing loss
It can cause you to misunderstand communication
It can cause you to miss important safety warnings
It can create unhealthy stress
Slide Show Notes
Noise can adversely affect us in a variety of ways. It can:
Result in temporary or permanent hearing loss
Cause you to misunderstand communication with co-workers
Cause you not to hear important safety warnings
Create stress that affects you physically and mentally
0507

9. How We Hear Sounds Sound waves enter the ear canal
Eardrum vibrations pass along tiny bones
Tiny hairlike cells flow back and forth
The auditory nerve sends signals to the brain that are registered as sound
Slide Show Notes
To understand how noise can adversely affect our hearing we must first understand how we hear sounds.
Sound waves enter the outer ear and travel down the ear canal where they strike the eardrum.
The eardrum vibrations are passed along by tiny bones, sometimes referred to as the hammer, anvil, and stirrup, into the inner ear.
The vibrations cause tiny hairlike cells in the inner ear to move back and forth, much the way a field of wheat or grass is moved by the wind.
The movement of the tiny hairlike cells stimulates the auditory nerve that sends the sound signal to the brain.
0507

10. How Hearing Is Damaged
Hearing ability relies on delicate parts that can be damaged in the inner and middle ear
Hairlike cells in the inner ear are flattened by high noise levels and injured over time
Hearing loss is gradual
Hearing damage is permanent
Slide Show Notes
As discussed on the previous slide, you can see that the hearing process consists of many delicate parts. If one of those parts is damaged, then hearing will also be damaged. Loud noise will cause the hair to lie flat. Once the noise stops, the hairs will spring back much the way a trampled field of grass will slowly spring back.
Eventually, over a long period of loud noise exposure, the tiny hairlike cells will take longer and longer to spring back until one day they are too damaged to return to their normal position. Have you ever heard someone say “The noise doesn’t bother me; I’m used to it”? The person is not getting used to the noise, but losing hearing function, so the noise doesn’t seem as loud and doesn’t bother him or her as much as it did in the past.
The most common way of losing hearing is through gradual damage to the delicate hairlike cells.
Once hearing is damaged, it is permanent.
Image Credit: OSHA
0507

11. Hearing Loss Hearing loss is any reduction in the ability to hear
Two types of loss
Temporary hearing loss (temporary threshold shift) may occur immediately following a high noise exposure
Permanent hearing loss (standard threshold shift)
Slide Show Notes
Hearing loss is any reduction in the ability to hear compared with that of a normal person of our age.
There are two types of hearing loss:
Temporary hearing loss (temporary threshold shift) may occur immediately following a high noise exposure. However, this loss is only temporary; a few hours, and full hearing will be restored.
Permanent hearing loss (standard threshold shift) is the result of permanent damage to the inner ear.
0507

12. Signs of Hearing Loss Difficulty hearing people speak
Inability to hear certain high-pitched or soft sounds
Noise or ringing in ears
Getting complaints that the radio or TV volume is too high
Slide Show Notes
Hearing loss often goes undetected because it is a gradual and pain-free process but there are some signs you should be aware of. Signs of hearing loss include:
Difficulty hearing people speak. Do people have to speak up or repeat what they say for you to hear them?
Inability to hear certain high-pitched or soft sounds. Do you have trouble hearing the ticking of a clock or a watch?
Noise or ringing in the ears.
Getting complaints that the radio or TV volume is too high.
Ask employees if they can think of any other possible signs of hearing loss that they or someone they know have experienced.
Image Credit: Tom Ouimet
0507

13. Evaluating the Noise Exposure Hazard
Conduct a noise survey
Identify and characterize high-noise sources
Identify impacted employees
Monitor impacted employees
Repeat monitoring
Slide Show Notes
In order to know if we are at risk of hearing loss, we must evaluate our noise exposure to determine if it is hazardous.
The first step in evaluating our noise exposure is to conduct a noise survey. A noise survey will:
Identify and characterize high-noise sources.
Identify employees who are impacted by high-noise levels.
Next, the noise exposure of employees at risk of high noise exposures are evaluated. Because employees move about during their workday, a noise dosimeter is typically used. The dosimeter records all the noise levels and computes the average noise exposure level for that particular employee. This information can be transferred to other employees that do similar jobs.
Monitoring is repeated whenever a change in production, process, or equipment influences noise-level exposures.
What was the monitoring strategy employed by your company? Who conducted the monitoring? Was it done internally or by an outside company? Discuss here.
Show trainees a map that indicates all the high-noise areas and the results of your company’s noise monitoring, if available.
Image Credit: Tom Ouimet
0507

14. Noise Hazards—Any Questions?
Any questions about the hazards of excessive noise and how to identify them?
Questions about signs and symptoms of hearing loss?
Questions about measuring hearing loss?
Slide Show Notes
Are there any questions about the hazards of excessive noise and how to identify them?
Any questions about signs and symptoms of hearing loss?
Any questions about measuring hearing loss?
0507

15. Elements of the Hearing Conservation Program
All employees exposed to >85 dBA for 8 hours must participate
You receive:
Baseline and annual audiograms
Annual training on hearing loss
Audiograms and PPE
Hearing protection is provided
Exposure assessment conducted periodically
Slide Show Notes
Employees whose noise exposures exceed an average of 85 dB over 8 hours must participate in our hearing conservation program.
As a participant in this program you will receive:
A baseline and annual audiogram
Annual training
Audiograms and PPE
Hearing protection will be provided to you
We will continue to conduct noise exposure assessments, particularly as our operation changes, to accurately assess each employee’s exposure.
0507

16. Audiometric Exams Exams can detect early signs of hearing loss
Typically measures hearing threshold at six frequencies
Hearing thresholds are compared with previous audiograms
Slide Show Notes
Audiometric exams are an essential element of our hearing conservation program and detect early signs of hearing loss.
These exams accurately measure our hearing ability in each ear and detect our threshold for hearing different frequencies of sound – typically 500; 1,000; 2,000; 3,000; 4,000; and 6,000 Hz.
The measured hearing thresholds are compared with previous audiograms to determine if a threshold shift, or a loss of hearing, has occurred.
0507

17. Standard Threshold Shift (STS)
Hearing loss has occurred if you have experienced a standard threshold shift (STS)
Hearing ability changed by an average of 10 dB
Revised hearing protection required for STS
Slide Show Notes
You will be considered to have a hearing loss if you experience a standard threshold shift (STS) during an annual audiogram. STS or hearing loss may be slight, moderate, or severe.
You will be found to have an STS if your threshold for hearing has increased an average of 10 dB or more at 2,000; 3,000; and 4,000 Hz in either ear from the baseline audiogram. When evaluating for STS, age is a factor. You will be notified within 21 days if an STS is detected.
If you have an STS we may ask you to wear hearing protection (if it was not previously worn) or we may ask you to wear a different type of hearing protection (one that offers more protection). Since hearing loss may also be attributed to other medical conditions (such as the use of medication or a recent injury), a further medical evaluation may be required.
0507

18. Has an STS Occurred? Baseline Annual Slide Show Notes
This graph shows a baseline and recent audiogram. Has an STS occurred?
Yes, the average threshold shift in the 2,000; 3,000; and 4,000 frequencies exceeds 10 dB.
Image Credit: Tom Ouimet
0507

19. An Example of Hearing Loss in Carpenters
Slide Show Notes
This graph demonstrates the severe hearing loss that can occur over long periods of time when exposed to high noise sources.
The 55-year-old carpenter would have a great deal of difficulty understanding anyone talking at a normal level.
After just a few short years of exposure, the 25-year-old carpenter has already experienced the hearing loss of a normal 50-year-old without noise exposure.
Image Credit: Tom Ouimet
0507

20. Hearing Protection Use
Voluntary use if exposed to an 8-hour TWA of dB
Mandatory use when:
Exposed to an 8-hour TWA of 90 dB
Exposed to an 8-hour TWA of 85 dB and have suffered an STS (hearing loss) or have not had a baseline hearing test
Slide Show Notes
OSHA requires hearing protection under different exposure conditions.
Hearing protection use is voluntary for employees exposed to an 8-hour TWA of dB.
Hearing protection becomes mandatory under the following conditions:
Exposed to an 8-hour TWA of 90 dB (or more)
Exposed to an 8-hour TWA of 85 dB and have suffered an STS (hearing loss) or have not had a baseline hearing test
The information on the slide is what OSHA requires. Your company may have internal rules that require the mandatory use of hearing protection by all employees if they are exposed to an 8-hour TWA of 85 dB. This would be an easier program to manage.
0507

21. Hearing Protection Devices Noise Reduction
Hearing protection devices must reduce employee noise exposure below an 8-hour TWA of 90 dB
Employees with STS, noise exposure reduced below an 8-hour TWA of 85 dB
Noise reduction ratio (NRR)
Earplugs: use 1/3 of NRR
Earmuffs: use 1/2 of NRR
Slide Show Notes
The purpose of hearing protection is to reduce your exposure to noise. The exposure must be reduced by the hearing protection device to at least an 8-hour TWA of 90 dB.
If you have suffered hearing loss and are classified as having experienced an STS, you must have hearing protection that reduces exposure to at least an 8-hour TWA of 85 dB.
Each hearing protection device is rated to reduce noise exposure by a certain number of decibels; this is called the noise reduction ratio (NRR). However, the listed NRR is a laboratory result. The real-world NRR will be significantly less because of inadequate fit and application.
For earplugs, assume the real-world NRR is less than 1/3 of the NRR listed on the package.
For earmuffs, assume the real-world NRR is about 1/2 of the NRR listed on the package.
Note that removing hearing protection devices for short periods of the day (e.g., 30 minutes) will reduce the real-world NRR even further. Always wear your hearing protection when in noisy locations.
What is the NRR of the hearing protection devices that your company is providing? Is it adequate?
0507

22. Hearing Protection Devices—Earplugs and Canal Caps
Must be properly inserted to seal the ear canal
Slowly roll and compress foam into cylinder
Insert into ear canal while compressed
Keeps noise from reaching the eardrum
Cotton is not an earplug
Slide Show Notes
There are many different styles and brands of earplugs, but they are all very similar. You can read the directions on the package, but, with most earplugs, you roll and compress the foam into a cylinder, insert it into your ear, and allow it to expand and fill your ear canal. Earplugs offer great protection from noise and are lightweight and unobtrusive. Just remember to make sure the plugs are clean before inserting them in your ear. Get a new pair at the beginning of each day.
Canal caps are useful for employees who are exposed to loud noise for short periods of time or someone who has to walk through a high-noise area to get from one department to another. They usually do not have the same protection as the plugs because they do not enter the ear canal; they merely cap the canal’s entrance.
Cotton balls are not hearing protection devices.
Bring samples of the types of hearing protection devices that your company makes available to employees. Describe how employees can obtain the hearing protection devices. Where do they go to get them? What do they have to do?
Image Credit: State of WA-WISHA Services
0507

23. Hearing Protection Devices—Earmuffs
Sealed against head with ears fully enclosed
Hair out from muffs
Glasses and caps do not interfere with seal
Headband adjusted so cushions exert even pressure
Cleaned with warm, soapy water and rinsed
Slide Show Notes
Earmuffs are generally used as a supplemental protection from noise. They might be used in addition to earplugs to help reduce noise exposure even further. Headphones from portable radios do not count as hearing protection devices. If the earmuffs do not fit perfectly or seal adequately, they can actually increase noise exposure because noise may actually echo inside the “muff,” thus increasing in dB before entering the ear. The following guidance should be followed when wearing earmuffs:
Muffs must fully enclose the ears and seal against the head.
Pull hair back and out from beneath the muffs.
Make sure glasses and caps don’t interfere with seal.
Adjust headband so cushions exert even pressure.
Clean muffs with warm, soapy water and rinse thoroughly.
0507

24. Any Questions? Any questions about audiometric testing?
Questions about our hearing protection program?
About when to use hearing protection?
About hearing protection devices?
Slide Show Notes
Are there any questions about audiometric testing?
Questions about our hearing protection program?
About when to use hearing protection?
About hearing protection devices?
0507

25. Key Things to Remember
Hearing is a very important sense – don’t lose it
Noise exposure over 85 dB can cause hearing loss
Hearing loss cannot be cured or repaired
Hearing tests are conducted annually and can detect hearing loss
Hearing protection devices must be worn in high-noise areas
Slide Show Notes
Hearing is a very important sense – don’t lose it.
Noise exposure over 85 dB can cause hearing loss.
Hearing loss cannot be cured or repaired.
Hearing tests are conducted annually and can detect hearing loss.
Hearing protection devices must be worn in high-noise areas.
Consider adding an additional bullet point describing the areas of high noise in your company’s facility.
0507