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Please read this before using presentation. This presentation is based on content presented at the Mines Safety Roadshow held in October 2008 and Exploration Safety Roadshow held in November 2008
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Please read this before using presentation • This presentation is based on content presented at the Mines Safety Roadshow held in October 2008 and Exploration Safety Roadshow held in November 2008 • It is made available for non-commercial use (e.g. toolbox meetings) subject to the condition that the PowerPoint file is not altered without permission from Resources Safety • Supporting resources, such as brochures and posters, are available from Resources Safety • For resources, information or clarification, please contact: ResourcesSafety@docep.wa.gov.au or visit www.docep.wa.gov.au/ResourcesSafety
Toolbox presentation: How can we stop noise damaging hearing
Outline 3 • Why is protecting our hearing important? • Terminology and setting the scene • Signs of NIHL • How much noise? • Managing noise • PPE NIHL = noise-induced hearing loss
What is the impact of NIHL? 4 Recognising NIHL Everyone appears to be mumbling Can’t hear conversations at home or work May misinterpret what many people say Have to ask people to repeat what they said – then they yell Consequences Hearing loss is insidious and irreversible Affects quality of life and is extremely isolating Increased opportunity for miscommunication (potential for poor outcomes)
Basic rules of working with noise The noise levels are described in decibels (dB) They can not be added or subtracted in the usual arithmetic way because the dB scale is logarithmic Two identical tools emitting noise of 90 dB(A) produce the combined noise level of 93 dB(A), not 180 dB(A) 5
Basic rules of working with noise (continued) 3 dB(A) increase corresponds to a doubling of sound energy 10 dB(A) increase corresponds to a 10 times increase of the sound energy 20 dB(A) increase corresponds to a 100 times increase of the sound energy 6
Standard for occupational noise Noise exposure — 85 dB(A) for 8 hours Peak noise level — 140 dB(lin) If you can’t hear speech one metre from source then background noise is too loud – exceeds 85 dB(A) 8
Incidence of hearing loss NIOSH (USA) reports that 49% of male, metal/non-metal miners will have a hearing impairment by age 50 (versus 9% for general population), rising to 70% by age 60 About 50% of WA mining employees between 40 and 50 years old have a significant threshold hearing shift – increases to 82% for those aged 50 and above Significant hearing threshold shifts > 20 dB(A) across both ears at 3,4 and 6 kHz
Examples of potential noise hazards Mining Jumbo drilling Angle grinding Ball mills Mobile plant Exploration High pressure air-booster RC drilling causes greater high impact noise Diamond drilling - high frequencies
Some risk factors 13 Duration and frequency of exposure • Tasks involving repetitive or sustained exposure to noise Peak noise • Tasks with sudden loud noise (acoustic shock) Communication requirements • Tasks that require communication between or to and from workers in noisy places
Addressing risk factors 14 Employer’s responsibility to reduce noise as much as possible (ALARP) – assess workplace noise, develop and implement noise control plan Employee’s responsibility to comply with noise management procedures Control measures developed by consultative process Role of safety and health representatives
Risk management approach 15 Hierarchy of controls • Elimination • Substitution • Isolation • Engineering • Administrative • PPE Ultimate aim of risk management is elimination of hazards, and PPE is used as a last resort More than one measure may be used to reduce exposure to hazard
Noise hazards – focus on the controls Undertake noise surveys of all equipment under usual operating conditions Noise footprint of equipment – show which parts should be avoided on a laminated A4 sheet Implement engineer controls prior to commissioning equipment Appropriate PPE can be supplied based on noise survey Consulting employees on their preferences on fit and comfort will improve their effectiveness as they will be used properly
Risk management approach (continued) 17 Design options – do it right from the start • ‘Buy Quiet’ programs – look for good noise and vibration characteristics • Workshop layout • Doubling distance from noise will halve noise level received by ear • Avoid work areas in corners with reflective surfaces Substitution, isolation and engineering options • Use damping materials and sound barriers • Change activity (e.g. reduce fan speed)
PPE – hearing protection considerations 20 Chosen for task – beware under- and over-protection issues Fit tested Provide information and instruction Maintained – and replaced as necessary Worn before entering noisy area – and left on Used correctly Address communication issues – workers should not be removing protection in noisy areas to talk to each other or speak on radios or phones
Reduction in protection with decreased wearing time Effectiveness of wearing an ear muff with a rating of 30 dB for an exposure time of one hour If earmuff removed or lifted to speak to fellow worker for total of 5 minutes in the one hour period, effective attenuation is 11 dB! 21