Noise at Work

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

2. Introduction • Noise at work and how it can affect you 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 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 1989 • - The Control of Noise at Work Regulations 2005 • Information, instruction, and training • - What we need to tell you 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! Hansen – managing safely

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

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

11. Sound • The human ear detects • Ranges between approximately 20 Hz to 20 000 Hz • Any sound less than 20 Hz • Infrasound • Any sound above 20 000 Hz • Ultrasound 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. Hansen – managing safely

13. The Ear 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 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 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 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 Hansen – managing safely

18. The Ear Hansen – managing safely

19. The Cochlea • Snail-shaped organ • Lined with over 20 000 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 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) 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 10000 times more intense, is assigned a sound level of 40 db. • This scale is based on powers or multiples of 10 Hansen – managing safely

22. Typical Noise Levels Remember that a doubling in sound represents an increase of only 3dB 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 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 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 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 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 Hansen – managing safely

28. Noise Induced Hearing Loss • An ‘normal’ audiogram 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 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 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 - 200 Pascals or 140dB • The sound at the ear is represented by (A) 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 - 200 Pascals or 140dB • This relates to sudden noise • the duties are similar to those required by the second action level 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 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 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 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 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 Hansen – managing safely

38. Exposure areas Hansen – managing safely

39. Exposure areas 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 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 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. Hansen – managing safely

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

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

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