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Hansen – managing safely 1 Noise at Work Mark Mallen Group Health and Safety Manager.

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Presentation on theme: "Hansen – managing safely 1 Noise at Work Mark Mallen Group Health and Safety Manager."— Presentation transcript:

1 Hansen – managing safely 1 Noise at Work Mark Mallen Group Health and Safety Manager

2 Hansen – managing safely 2 Introduction Noise at work and how it can affect you

3 Hansen – managing safely 3 Objectives What is noise? What is sound? How do we hear? Measuring noise? Hearing Loss The Law –Employer duties –Employee duties PPE –Where, what and when

4 Hansen – managing safely 4 Content What is noise? Sound How do we hear? The measurement of noise Hearing Loss The Law - Noise at Work Regulations The Control of Noise at Work Regulations 2005 Information, instruction, and training - What we need to tell you

5 Hansen – managing safely 5 What is Noise? Noise –Noise is unwanted sound. –One person’s music could be another’s noise! –The ear does not differentiate between noise and sound - The brain does that!

6 Hansen – managing safely 6 What is Noise? Effects Short term –Annoy –Distract Long term –Deafness –Tinnitus –Noise Induced Hearing Loss (NIHL)

7 Hansen – managing safely 7 Sound The sensation produced via the ear, –results from fluctuations in air pressure –Caused by vibrating air molecules –The source of the sound vibrates –Creates a sound pressure wave

8 Hansen – managing safely 8 Sound Like ripples on a pond – sound pressure wave

9 Hansen – managing safely 9 Sound A Sound Wave –created by a vibrating object: The vocal chords A guitar string A machine Traffic The diaphragm of a radio speaker

10 Hansen – managing safely 10 Sound Air moves back and forth –The frequency of a wave If a particle of air undergoes 1000 vibrations in 2 seconds –Then the frequency of the wave is 500 vibrations per second The unit of frequency is the hertz (abbreviated Hz), where: –1 Hertz = 1 vibration/second

11 Hansen – managing safely 11 Sound The human ear detects –Ranges between approximately 20 Hz to Hz Any sound less than 20 Hz –Infrasound Any sound above Hz –Ultrasound

12 Hansen – managing safely 12 How do we hear Sound? The Ear –The outer ear Collects and channels sound to the middle ear. –The middle ear Transforms the energy of a sound wave into internal vibrations via a bone structure. –The inner ear The inner ear transforms these vibrations into nerve impulses, which can be transmitted to the brain.

13 Hansen – managing safely 13 The Ear

14 Hansen – managing safely 14 The Outer Ear Consists of an earflap and an ear canal The earflap protects the middle ear and eardrum It also channels sound waves to the eardrum Sound is still a sound pressure wave At the eardrum, the wave converts into vibrations

15 Hansen – managing safely 15 The Middle Ear An eardrum –A membrane, which connects to the hammer Three tiny, interconnected bones –Hammer, anvil & stirrup –Act as levers to amplify the sound wave –The stirrup concentrates sound wave by 15 –This enhances our ability of hear faint sounds

16 Hansen – managing safely 16 The Middle Ear The Eustachian tube –Connects the middle ear via a tube to the mouth –Allows for the equalization of pressure within the air-filled cavities –When clogged i.e. During a cold, the ear cavity is unable to equalise pressure; often leads to earaches and other pains The stirrup transmits vibrations to the inner ear, via the oval window

17 Hansen – managing safely 17 The Inner Ear Full of a water like fluid The stirrup creates a wave within this fluid The inner ear consists of –A cochlea –The semicircular canals –And the auditory nerve The fluid and nerve cells of the semicircular canals provide no roll in the task of hearing –They serve as accelerometers for detecting accelerated movements –Assist in the task of maintaining balance

18 Hansen – managing safely 18 The Ear

19 Hansen – managing safely 19 The Cochlea Snail-shaped organ –Lined with over hair-like nerve cells –These nerve cells differ in length by minuscule amounts –They have different degrees of resiliency to the fluid –The hair-like nerve cells are set in motion by the wave –Each hair cell has a natural sensitivity to a particular frequency of vibration –When the wave matches the natural frequency of the nerve cell, an electrical impulse is released –Which passes along the auditory nerve to the brain –The brain then interprets the qualities of the sound upon reception of these electric nerve impulses

20 Hansen – managing safely 20 The Measurement Of Noise Decibels –Humans have very sensitive ears –The lowest sound corresponds to the displacement of air particles by one-billionth of a centimetre –Known as the ‘threshold of hearing’ –The most intense sound Which the ear can detect without suffering any damage –More than one billion times more intense –Known as the ‘threshold of pain’ Since the range of intensities is so large, a scale based on multiples of 10 is used –Known as a logarithmic scale –The scale for measuring intensity is the decibel scale Decibels are written as: db At the ear db (A)

21 Hansen – managing safely 21 The Measurement of Noise The threshold of hearing is assigned a sound level of 0 decibels, abbreviated 0 dB. A sound, which is 10 times more intense, is assigned a sound level of 10 dB. A sound, which is 10 x 10 or 100 times more intense, assigned a sound level of 20 db. A sound, which is 10 x 10 x 10 or 1000 times more intense, is assigned a sound level of 30 db. A sound, which is 10 x 10 x 10 x 10 or times more intense, is assigned a sound level of 40 db. This scale is based on powers or multiples of 10

22 Hansen – managing safely 22 Typical Noise Levels SourceIntensity Level Threshold of Hearing - TOH0 dB Rustling Leaves10 dB Whisper20 dB Normal Conversation60 dB Busy Street Traffic70 dB Vacuum Cleaner80 dB Large Orchestra98 dB Walkman at Maximum Level100 dB Front Rows of Rock Concert110 dB Threshold of Pain - TOP130 dB Military Jet Takeoff140 dB Instant Perforation of Eardrum160 dB Remember that a doubling in sound represents an increase of only 3dB

23 Hansen – managing safely 23 Hearing Loss The ear can be easily damaged, by: –Medical conditions –Accidents –Drugs –Congenital conditions –Social activities –Prolonged exposure to high noise levels Workers at risk of hearing damage are usually : –Metal work –Construction –Quarrying –Steel work –Mining –Noisy industries Exposure above 90 db (A) is likely to cause damage This is known as noise induced hearing loss

24 Hansen – managing safely 24 Noise Induced Hearing Loss Chronic NIHL Damage is caused to the sensitive cells in the cochlea Occurs gradually from exposure to less intense noise levels

25 Hansen – managing safely 25 Noise Induced Hearing Loss Associated with exposure to high intensity, continuous noise The amount of sound that is capable of producing cochlear damage and subsequent hearing loss is based upon –The equal energy concept Therefore, it is the total sound energy delivered to the cochlea that is relevant in predicting injury and hearing loss Both an intense sound presented to the ear for a short period and a less intense sound that is presented for a longer period will produce equal damage to the inner ear

26 Hansen – managing safely 26 Noise Induced Hearing Loss Chronic NIHL has two phases Temporary Threshold Shift – TTS –The first stage –Brief hearing loss, ‘ringing in the ears’ –Completely resolves after a period of rest auditory fatigue –Most studies indicate that no sensory cell damage occurs – After repeated exposure to noises –A Permanent Threshold Shift - PTS will occur

27 Hansen – managing safely 27 Noise Induced Hearing Loss Permanent threshold shift – PTS –This is the second stage of chronic NIHL –An irreversible increase in hearing thresholds –Irreversible hair cell damage Once you have it, it is too late –Sufferers report difficulty understanding speech rather than hearing speech –Particularly noticeable in environments with significant background noise

28 Hansen – managing safely 28 Noise Induced Hearing Loss An ‘normal’ audiogram

29 Hansen – managing safely 29 Noise Induced Hearing Loss An audiogram showing the classic ‘dip’ in hearing performance –Characterised by a loss of consonant discrimination –Consonant sounds such as f, s, t, d, sh, and k are essential to the intelligibility of speech

30 Hansen – managing safely 30 Noise Induced Hearing Loss Socioacusis –even people with quiet jobs may suffer –Such non-occupational NIHL is also called socioacusis. Sources of non-occupational noise include: –Gunfire –Loud music –Open vehicles –Power tools

31 Hansen – managing safely 31 The Law Noise at Work Regulations 1989 Place responsibilities –employers –Employees –People who make and supply noisy machinery The regulations introduced three thresholds: –First Action Level - 85dB(A) –Second Action Level - 90dB(A) –Peak Action Level Pascals or 140dB The sound at the ear is represented by (A)

32 Hansen – managing safely 32 The Law First Action Level - LEP, d 85dB(A) –When you have to raise your voice to be heard at 2 metres –The employee must be trained –hearing protection must be made available upon request Second Action Level - LEP, d 90dB(A) –When you have to raise your voice to be heard at 1 metre –A noise reduction programme must be implemented –Areas must be marked –Employees must be provided with hearing protection, which must be worn Peak Action Level Pascals or 140dB –This relates to sudden noise –the duties are similar to those required by the second action level

33 Hansen – managing safely 33 The Law Employers duties –Get the noise levels assessed by competent people –Keep a record –Where exposure is at, or above, any of the action levels: Inform personnel that there is a noise hazard Inform them of what to do Where the exposure needs to be controlled, quieten the workplace, if this can be done Between the first and second action levels –Provide ear protection (ear muffs or plugs) –Inform workers of the risk to their hearing

34 Hansen – managing safely 34 The Law Where use of protection is compulsory –Ear protection zones should be marked –Make sure that everyone who goes into a marked zone, even for a short time, uses ear protection –Check to make sure the control measures are working –Make sure the equipment you provide is kept in good condition If people work in noise at, or above, the second or the peak action level The regulations still require the reduction of noise exposure by means other than ear protectors, as far as this is reasonably practicable

35 Hansen – managing safely 35 The Law Employees duties –Wear the ear protection (earplugs or earmuffs) provided –At the second or peak action levels might be reached –Every entry into an area marked as an ear protection zone Use any other equipment the employer provides –For example, if the machine is meant to have a silencer fitted- don't take it off Look after any equipment provided under the regulations Report any equipment defects

36 Hansen – managing safely 36 The Law –Changes Are Coming! The control of noise at work regulations 2005 Come into force on 6th April 2006 Exposure limit values and action values The lower exposure action values –A daily or weekly personal noise exposure of 80 db (A) –A peak sound pressure of 135 db The upper exposure action values –A daily or weekly personal noise exposure of 85 db (A) –A peak sound pressure of 137 db The exposure limit values A peak sound pressure of 140 db

37 Hansen – managing safely 37 Information, Instruction, And Training What we need to tell you –Exposure areas above the lower exposure action values –What we are doing to control risks and exposures –Where and how people can obtain hearing protection –How to report defects in hearing protection and noise- control equipment –Duties under the noise regulations 2005 –What you should do to minimise the risk Such as the proper way to use hearing protection and other noise-control equipment How to look after it and store it, and where to use it

38 Hansen – managing safely 38 Exposure areas

39 Hansen – managing safely 39 Exposure areas

40 Hansen – managing safely 40 Information, Instruction, And Training What we are doing to control risks and exposures –Established advisory hearing protection zones –Sourcing noise reduction blades –Provide hearing protection Where and how people can obtain hearing protection –Freely available from dispensers or production manager How to report defects in hearing protection and noise-control equipment –Report to supervisor or manager

41 Hansen – managing safely 41 Information, Instruction, And Training Duties under the noise regulations 2005 –Wear the ear protection (earplugs or earmuffs) provided –Use any other equipment the employer provides under the regulations –Look after any equipment provided under the regulations –Report any equipment defects

42 Hansen – managing safely 42 Information, instruction, and training Earmuffs –Make sure they totally cover your ears, –Fit tightly and there are no gaps around the seals. –Don’t let hair, jewellery, glasses, hats etc interfere with the seal. –Try and keep the seals and the insides clean. –Don’t stretch the headband too much – make sure it keeps its tension.

43 Hansen – managing safely 43 Information, Instruction, And Training Earmuffs

44 Hansen – managing safely 44 Information, Instruction, And Training Earplugs –They can be difficult to fit properly –Practice fitting them and get help if you are having trouble –They can look like they are fitted properly –Clean your hands before you fit earplugs, and don’t share them –Some types you use only once –Others can be re-used and even washed –Make sure you know which type you have Semi-inserts/caps –Follow the same advice as for earplugs –Make sure any headband keeps its tension

45 Hansen – managing safely 45 Information, Instruction, And Training Earplugs

46 Hansen – managing safely 46 Information, Instruction, And Training Remember – hearing protection is provided to protect you, if you do not use it, you may lose it Remember – if in doubt, ask

47 Hansen – managing safely 47 Objectives What is noise? What is sound? How do we hear? What unit do we use to measure noise? How we get Hearing Loss The Law –Employer duties –Employee duties PPE –Where, what and when

48 Hansen – managing safely 48 Noise at Work Thanks for Listening Any questions


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