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Introduction

Employers are required to take all practicable steps to ensure their Employees are not exposed toharmful noise. Where all practicable steps have been taken, but the risk is still present, Employers areto bring the hazard to every Employees attention by way of signs, notices, labelling or otherappropriate means. The Employer must also clearly indicate the type of hearing protection to be usedby Employees while exposed to that noise hazard, and where the hearing protection devices are kept.

Main Points

Noise may be defined as unwanted sound. Excessive noise, that is noise above thedamage risk criteria of 85 dB(A) as measured on an eight hour working day, is a health

hazard Unprotected exposure to a peak level of 140 dB(A) for any duration will cause noise

induced hearing loss. Legislation requires that no worker be exposed to such noise atall, whether wearing hearing protection devices or not

Deafness is generally irreversible, and even partial hearing loss can seriously affectsomeones ability to communicate. It can also affect balance, and this, combined withdifficulty in communications, can make it difficult to continue in employment and canlessen enjoyment of life.

Discussion Points

The following scale is presented for people not wearing hearing protection and sets out

maximum time limits one could be exposed without suffering permanent hearing loss.The scale assumes constant sound with no fluctuations.

Maximum time exposure to sound per day before permanent loss of hearing occurs:

dB(A) Max. Exposure Time Per DayHand saw 85 480 minutes (8 hours)Power drill 88 240 minutes (4 hours)Heavy truck 91 120 minutes (2 hours)Lawnmower 94 60 minutes (1 hour)Power saw 97 30 minutesPneumatic drill 100 15 minutesConcrete saw 103 8 minutesLoud stereo 106 4 minutesCommercial jet 109 2 minutesTrail bike 112 1 minuteChainsaw 115 30 seconds

Threshold of Pain 120 PainVehicle horn 120 Will cause painPowder fired fastener 140 Will result in hearing lossArtillery fire 160 Immediate physical damage

Hearing protection is no longer graded. Grades 1-5 have been replaced with Class 1-5 Hearing protection devices are classed according to their efficiency in protecting hearing,

and higher graded equipment is necessary as the level of exposure increases. Thefollowing table is offered as a guide:

P.T.O

NOISE

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Hearing Protection Class Leq (8hour) dB(A) Protection (Approved)Class 1 < 90dB Earplugs/EarmuffsClass 2 90 -