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Environmental Health
~ Ratonga Tiaki Taiao

noise microphone

Noise Protection

Save yourself an ear bashing protect your hearing properly.

Do you frequently use a chainsaw, lawnmower, tractor, rotary hoe, motorcycle, go-kart, outboard motor, firearm or any power tools? If so, your hearing needs proper protection.

It is not only workers who are exposed to noisy machinery all day every day who need hearing protection. Equipment used on the farm, around the house, or in spare time activities is often noisy enough to damage your hearing even if you are only exposed to it for a few hours now and then.

How can you tell if you need protection?

A simple rule of thumb is this:

If the noise is so loud that you have to shout to be understood by someone standing less than a metre away, you need hearing protection.

What kind of hearing protection should you buy?

All good protective ear muffs and plugs are marked with a grade between 1 and 5. The louder the noise you are exposed to, the higher the grade you need to have.


The following lists give the minimum grade you need for various types of equipment.

Grade 3 or higher (Grade 3 suitable for noise levels up to 103dB)

  • For tractors
  • Petrol driven chainsaws
  • Motorised backpacks for sprayers, scrubcutters
  • Motor powered agricultural machinery

 Grade 2

  • For lawnmowers
  • Retort hoes
  • Electric chainsaws
  • Power tools such as electric drills, sanders, saws, grinders
  • Firearms
  • Outboard motors (above 25hp)
  • Motorcycles
  • Go-karts

Noise and Hearing

Loud noise physically damages delicate cells in the ear which are essential to hearing. Repeated loud noise actually destroys these cells permanently.

When this happens the person can no loner hear some sounds, including some common speech sounds such as t, s, p, f. Speech becomes blurred and hard to understand. Conversation therefore becomes difficult, crating problems in the family, at work and in social situations.

Hearing Damage

How long does it take for this damage to happen?

This depends on how loud the noise is, and how long you are exposed to it. The table gives the maximum noise level produced by common types of equipment. Regular exposure to this level of noise for longer than the time shown can cause damage - unless hearing protection is worn.

Equipment Maximum Noise Level (decibels) Enough Exposure to Damage Hearing
Petrol driven Chainsaw 115 30 seconds
Motorcycle (off road) 110 2 minutes
Go-Kart 110 2 minutes
Tractor 105 4 minutes
Outboard motor (above 25hp) 105 4 minutes
Power tools 100 15 minutes
Lawnmower 95 60 minutes
Rotary Hoe 95 60 minutes

 More Information

Noise Control: Your Rights - NZ Consumer

Excessive noise is a health hazard, where noise cannot be reduced at source, wear hearing protectors. The louder the noise the higher grade of hearing protection required.


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