Noise in the workplaceWH Kelly Ltd

Greg GillardInjury Prevention Consultant

Noise• Reactions and emotions

that we associate with:– Screeching tyres – Breaking glass – Mr. Whippy– Dentist drill– Music

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

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

17-year old girlLow noise exposure

• Normal cochlea

• Receptors intact

76-year old manLow noise exposure

• Fewer receptorsbut still intact

59-year old manHigh noise exposure

• Damaged cochlea

• Receptors destroyed

Safe Noise Levels

Low noiseNormal 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

Loud noise levels damage the first turn of cochlea

High noiseDamaged cochlea

High Frequencies

Damaged

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?

NoiseEquipment Decibels Time Limit

– Power drill 88 4 hours– Heavy truck 91 2 hours– Lawnmower 94 1 hour– Power saw 97 30 mins– Pneumatic drill 100 15 mins– Concrete saw 103 8 mins– Loud stereo 106 4 mins– Commercial jet 109 2 mins– Trail bike 112 1 mins– Chainsaw 115 30 secs– Powder Powered Tools 140 hearing damage

Hazardous noise exposures are cumulative

Work

Home

NOISE AND ACOUSTICS

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

– 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 Plugs1. 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

3. Insert earplug well into ear canal and hold until it fully expands

Which ear is protected?

1 2 3

And so the problem grows…..

For more info……….

ACC website• www.acc.co.nzDepartment of Labour website

• www. http://www.dol.govt.nz