Transcript 17-year old girl Low noise exposure Normal

Noise in the workplace
WH Kelly Ltd
Greg Gillard
Injury Prevention Consultant
Noise
• Reactions and emotions
that we associate with:
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Screeching tyres
Breaking glass
Mr. Whippy
Dentist drill
Music
Noise and Acoustics
• Noise-induced Hearing Loss
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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
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
Exposure
76-year old man
17-year old girl
Low noise
Low noise exposure
• Normal cochlea exposure
• Fewer
• Receptors intact
receptors
but still
intact
59-year old man
High noise exposure
• Damaged
cochlea
• Receptors
destroyed
Safe Noise Levels
Low noise
Normal
cochlea
At safe noise levels,
sound waves move along
the cochlea without
damaging receptor cells
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
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
How often do we see this?
Noise
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Equipment
Power drill
Heavy truck
Lawnmower
Power saw
Pneumatic drill
Concrete saw
Loud stereo
Commercial jet
Trail bike
Chainsaw
Powder Powered Tools
Decibels
Time Limit
88
4 hours
91
2 hours
94
1 hour
97
30 mins
100
15 mins
103
8 mins
106
4 mins
109
2 mins
112
1 mins
115
30 secs
140
hearing damage
NOISE AND ACOUSTICS
Hazardous noise exposures are cumulative
Work
Home
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
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
Controlling Noise
• Ear Muffs
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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
Fitting Ear Plugs
1. Roll
entire earplug into a
crease-free cylinder
2. Pull Back
3. Insert
earplug well
into ear
canal and
hold until it
fully expands
pinna by reaching over
head with free hand,
gently pull top of ear up
and out
Which ear is protected?
1
2
3
And so the problem grows…..
For more info……….
ACC website
• www.acc.co.nz
Department of Labour website
• www. http://www.dol.govt.nz