1. Noise in the workplace WH Kelly Ltd
Greg Gillard
Injury Prevention Consultant

2. Noise Reactions and emotions that we associate with: Screeching tyres
Breaking glass
Mr. Whippy
Dentist drill
Music
Note: it is imperative that the noise section of this course is delivered in its entirety.
Use the Slides provided to review the information on noise is comprehensive because of the frequency and severity of noise induced hearing loss in the construction industry.
The objectives of the section on Noise are to:
ensure Trainees understand how hearing loss occurs,
understand the controls needed to prevent hearing loss,
and to motivate them to use the controls on site when required.
This section goes into detail about the ear and how it is affected by noise. Under the principles of adult learning, know the “why” as well as the “what” will help trainees better understand the impact on them. The section also looks at different noise levels produced by construction activities and the allowable noise levels and times of exposure for the activities. The section also demonstrates how to properly fit ear plugs and ear muffs.
It is vital that this section is run in its entirety – as a review/survey of a sample of Trainees will be conducted on the impact of this Module once it has been delivered to 10,000 Trainees.
What comes to mind when you hear these sounds:
Screeching brakes – car crash, Idiot, Drag Race
Breaking Glass – Oh OHH, Who dropped it?
Mr Whippy – Ice Cream
Dentist Drill – ouch
Music – relaxation, entertainment.
Demonstrate the affects of mild, moderate and severe hearing loss using the embedded file. You will hear the affects of hearing loss due to 95dB exposure over a working life from 18 to 65 years. Use the track until you have clearly demonstrated the affects.
Hearing Loss Audio
Run time 2:13
This audio clip demonstrates how 95dB will affect a worker's hearing over time: 18 years to 65 years of age. The following examples are demonstrated:
Normal hearing of an 18 year old
2 years on the job while exposed to 95dB
2 years on the job with 95 dB exposure – in a crowded place
Normal hearing again
40 year old exposed to 95dB
40 year old with 95dB exposure – in a crowded place
Normal hearing
65 year old exposed to 95dB

3. Noise and Acoustics Noise-induced Hearing Loss Causes no pain
Causes no visible trauma
Leaves no visible scars
Is unnoticeable in its earliest stages
Accumulates with each over-exposure
Takes years to diagnose
Is permanent and almost always preventable
Noise damage is different from most other occupational injuries. It causes no pain or visible trauma (the ears do not bleed when hearing is being damaged), it leaves no visible scars, it is unnoticeable in its earliest stages (workers with noise-induced hearing loss often do not even notice themselves that they are losing hearing until it is too late), it accumulates with each over-exposure, and it generally takes years to diagnose. But Noise-Induced Hearing Loss (NIHL) is permanent and 100% preventable.
Many people believe hearing loss results in living in a silent world, when in fact it can be frustrating and annoying – hearing sounds but not being able to understand.
Many types of hearing loss result in conditions such as tinnitus, a condition which results in constant ringing in the ear.

4. How We Hear
Nerve cells in the cochlea are tuned to specific frequencies
Base of the cochlea is sensitive to high frequency sounds
Tip of the cochlea is sensitive to low frequency (bass/deep) sounds
Cochlea Demonstration File
Run time: Very Short
You can play this video again by clicking on the image on the right of the slide.
This is image is showing the position of the outer and inner ear from the left side of the picture. The ear lobe or cartilage is
The cochlea is the auditory (hearing) portion of the inner ear. Its core component is the organ of Corti, the sensory organ of hearing, which is distributed along the partition separating fluid chambers in the coiled tapered tube of the cochlea. Looks a little like a curled Koru frond.
The cochlea is tuned in different areas to respond to different tones.
The base of the cochlea is sensitive to high frequency sounds -- it is this part of the cochlea that is damaged when loud noise enters the ear. It makes little difference whether the incoming sound is high-frequency or low-frequency – ANY loud noise will cause a high-frequency hearing loss, because the region of the cochlea hit hardest by incoming sound waves is the region where the high-frequency receptor cells are located.
The base of the cochlea is at the start of the video and the tip
<Click> mouse to play animation and tone sweep. The animation and tone sweep will come full screen and play. The animation shows how the cochlea is tuned in different areas to respond to different tones. Replay the animation as often as necessary by clicking on the animation.

5. Exposure 76-year old man Low noise exposure
Fewer receptors but still intact
17-year old girl
Low noise exposure
Normal cochlea
Receptors intact
59-year old man
High noise exposure
Damaged cochlea
Receptors destroyed
Here, we show actual magnified photos of human cochlea with various stages of damage. These cochleas vibrate with sound waves.
The magnified photo of a cochlea from a 17 year-old girl shows nerves and receptor cells still intact (indicated by the dark areas in the first turn of the cochlea.)
The second photo of a 76 year-old shows fewer receptor cells due to aging (some white gaps in the receptor cells), but still intact.
The third photo of a 59 year-old noise exposed man shows significant destruction of the receptor cells. This third photo shows that noise damages hearing much more than aging alone, and much faster.
If you keep poor practice up, you will end up with a cochlea (inner ear) that looks like the picture on the right.

6. Safe Noise Levels Low noise Normal cochlea
At safe noise levels, sound waves move along the cochlea without damaging receptor cells
Here is a depiction of what is happening mechanically inside the cochlea. At safe noise levels, sound waves move along the cochlea without damaging the receptor cells.
An analogy is a car traveling around a bend in the road at a safe speed. It makes the turn without problem.

7. Loud Noise Levels Loud noise levels damage the first turn of cochlea
High noise Damaged cochlea
Loud noise levels damage the first turn of cochlea
(Animation timed to play automatically.) In high noise, incoming sound waves strike the first bend of the cochlea with such force that they first fatigue – and eventually destroy – the receptor cells. The damage occurs where the high-frequency receptors are located; thus, noise causes a high-frequency hearing loss, regardless of whether the incoming sound is low-frequency or high-frequency noise.
Using the car analogy, a car traveling around a bend in the road at an unsafe and fast speed will crash when it gets to the corner.
Remember that noise is cumulative over a period of time.
High Frequencies Damaged

8. that background noise is hazardous
Noise And Acoustics
Noise And Acoustics
If you must RAISE YOUR VOICE TO BE UNDERSTOOD over the background noise when standing about 1 metre away from somebody
that background noise is hazardous
Here is a good rule of thumb to use in determining whether background noise is 85 dB or higher: If you must raise your voice to be understood by somebody about one metre away, that background noise is hazardous (review question).
When reading the slide, raise your voice to demonstrate the point.
Note to Trainees that the only accurate way of measuring noise exposure is through scientific methods using a sound meter or noise dosimeter.
This slide has an animated “fly in” for the Decibels and Time Limit.
The order of “click” is
88, 4hours
91-97, 2hours-30mins, and 15mins-4mins
and 2mins-30seconds and 140 Hearing damage
You can then get the class to guess the maximum time limit on each “click” item. Write them down on the whiteboard and then compare them to what is actually on the slide.
This slide shows a list of common activities, the typical noise levels they produce and the approximate time you can be exposed to those levels.
Point out that if you are exposed to one activity and noise level for a period of time, to determine the actual Time Weighted Average ( the allowable level of noise over an 8 hour day), add the noise level and the period of exposure for all activities.
For example, if you are exposed to a power saw for 30 minutes, you cannot be exposed to any other noise level over 85 dB for the rest of the day.
Remember that the effects are cumulative. If you’ve had your 85dB Time Weighted Average at work, and you blast your stereo or are exposed to other noise over 85dB you will suffer hearing loss.
Note: All grades of Class Five hearing protection are rated to a maximum of 110dB over a time period. Any noise attenuation over that rating has to be specially engineered.

9. How often do we see this?
Too often workers who are using noisy machinery/tools will be wearing hearing protection however their workmates standing in the near vacinity are not.
All workers working close to machinery need to be wearing hearing protection

10. Noise Equipment Decibels Time Limit Power drill 88 4 hours
Heavy truck 91 2 hours
Lawnmower 94 1 hour
Power saw mins
Pneumatic drill mins
Concrete saw mins
Loud stereo mins
Commercial jet mins
Trail bike mins
Chainsaw secs
Powder Powered Tools 140 hearing damage
This slide shows a list of common activities, the typical noise levels they produce and the approximate time you can be exposed to those levels.
Point out that if you are exposed to one activity and noise level for a period of time, to determine the actual Time Weighted Average ( the allowable level of noise over an 8 hour day), add the noise level and the period of exposure for all activities.
For example, if you are exposed to a power saw for 30 minutes, you cannot be exposed to any other noise level over 85 dB for the rest of the day.
Remember that the effects are cumulative. If you’ve had your 85dB Time Weighted Average at work, and you blast your stereo or are exposed to other noise over 85dB you will suffer hearing loss.
Note: All grades of Class Five hearing protection are rated to a maximum of 110dB over a time period. Any noise attenuation over that rating has to be specially engineered.

11. NOISE AND ACOUSTICS Hazardous noise exposures are cumulative Work Home
Noise exposure is cumulative, this means if you are exposed to long periods of noise at work and then go to a further noisy environment the exposure should be added to get a true reflection of overall exposure.

12. Controlling Noise
How can you control your exposure to dangerous levels of noise?
Use the control hierarchy – eliminate, isolate, minimise
Remove plant from the immediate work area
Isolate using soundproofing, do the job at time when others are not in the work area
Use new technology that is quieter
As a last resort minimise using PPE – ear muffs and plugs

13. Controlling Noise Ear Muffs and Ear Plugs
Minimise your exposure to damaging noise levels
Classified 1-5 by the amount of noise reduction they provide
It can be dangerous to have too much or too little protection
Many different types and varieties to suit individuals
Ear muffs and plugs are not “graded” they are now “classified” according to their real-ear attenuation capabilities – the amount of noise reduction, in decibels, they provide.
The classifications according to their efficiency in protecting hearing is shown in the chart below:
If too much protection is provided, too high a class, workers may not be able to hear noises, conversations, instructions, etc. that they need to hear. They may end up not wearing the PPE or they may end up constantly removing it to hear what they need to hear. If the protection class is too low, workers will be exposed to damaging levels of noise
Note: All grades of Class Five hearing protection are rated to a maximum of 110dB over a time period. Any noise attenuation over that rating has to be specially engineered.

14. Controlling Noise Ear Muffs
Must give you a good seal around the outer ear
Must be worn directly over the ear
Remove hair from around the muffs
Don’t wear over hoodies
Earmuff Fit
The best earmuff fit is only obtained when there is a proper seal around the pinna (the outer ear). Remove hair or other obstructions that may interfere with a good seal between the earcup cushion and the head.
Place earcups over each outer ear
Adjust the headband by sliding the headband up or down at the attachment buttons
The ear cushions should seal firmly against the head
Many worksites require safety eyewear. Does wearing an earmuff over safety eyewear break the seal, and reduce attenuation of the earmuff? From testing performed on five different models of safety glasses with different models of earmuffs, we find that the effect upon attenuation is mostly dependent upon the width of the eyeglass frame where it meets the earmuff cushion. When that temple arm of the frame is wide (5-6 mm), it can cause leakage resulting in a decline of 5 dB. But when that temple arm is thin (1-2 mm), the effect on attenuation is negligible.

15. Fitting Ear Plugs 1. Roll entire earplug into a crease-free cylinder
2. Pull Back pinna by reaching over head with free hand, gently pull top of ear up and out
1. Roll entire earplug into a crease-free cylinder
3. Insert earplug well into ear canal and hold until it fully expands
For earplugs, effective protection is dependent upon deep insertions. With foam earplugs, this is accomplished by following these three steps:
Roll down the foam earplug to a small crease-free cylinder
Straighten out the bend in the ear canal by reaching over the head with the free hand, and pulling the ear up and out.
Insert the earplug well into the ear canal and hold it in place a few seconds while the foam fully expands
Note: to remove earplugs they should be twisted or gently rolled to assist its removal.

16. Which ear is protected? 1 2 3
Just having an earplug in the ear is not a guarantee of protection. In the photos shown here the photo on the right shows the proper fitting.
There are two ways to determine if the earplug is in far enough to provide adequate protection:
Visual Check. When viewed directly from the front, the end of a properly-fit earplug should not be visible.
Acoustic Check. Cup your hands tightly and place them over your ears, then release. When earplugs are properly fit and doing their job, there should be no noticeable change in the noise level. If the earplugs are not inserted far enough, there will be a noticeable change in the noise when hands are cupped over the ear.

17. And so the problem grows…..
The problem is ongoing….
Young people of today are listening to loud music, IPODS, cars etc. Where will they be in 20 years?

18. For more info………. ACC website www.acc.co.nz
Department of Labour website
www.