Department of Consumer and Employment Protection Resources Safety 1 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: or visit

Toolbox presentation: How can we stop noise damaging hearing

Department of Consumer and Employment Protection Resources Safety 3 Outline 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

Department of Consumer and Employment Protection Resources Safety 4 What is the impact of NIHL? 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)

Department of Consumer and Employment Protection Resources Safety 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

Department of Consumer and Employment Protection Resources Safety 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

Department of Consumer and Employment Protection Resources Safety Typical noise levels of common sounds Noise sourcedB(A) 30 m from jet aircraft140 Chainsaw110 Kerbside of busy road80 Conversational speech60 Quiet bedroom at night30 7

Department of Consumer and Employment Protection Resources Safety 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

Department of Consumer and Employment Protection Resources Safety Typical noise levels at operator’s ear level Noise source Noise range dB(A) Haulage truck80-89 Dozer82-85 Excavator81-86 Jumbo drill Impact wrench Angle grinder Airleg drill

Department of Consumer and Employment Protection Resources Safety Average noise exposure in WA mining industry Average noise exposure Time to reach exposure standard if not protected Surface miners 94 db(A)1.0 hour Underground miners 101 dB(A)12 minutes All miners 96 dB(A)38 minutes 10

Department of Consumer and Employment Protection Resources Safety 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

Department of Consumer and Employment Protection Resources Safety 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

Department of Consumer and Employment Protection Resources Safety 13 Some risk factors 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

Department of Consumer and Employment Protection Resources Safety 14 Addressing risk factors 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

Department of Consumer and Employment Protection Resources Safety 15 Risk management approach 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

Department of Consumer and Employment Protection Resources Safety 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

Department of Consumer and Employment Protection Resources Safety 17 Risk management approach (continued) 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)

Department of Consumer and Employment Protection Resources Safety Noise control – design

Department of Consumer and Employment Protection Resources Safety Noise control – design

Department of Consumer and Employment Protection Resources Safety 20 PPE – hearing protection considerations 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

Department of Consumer and Employment Protection Resources Safety 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! Wear time Effective attenuation 60 minutes30 dB 55 minutes11 dB 50 minutes8 dB 45 minutes6 dB 21