Occupational Noise Exposure and Hearing Conservation

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Workers can be exposed to a wide array of noise exposures doing different tasks. They also may be exposed to noise while at sporting venues or participating in variuos recreational activities. Evaluating noise exposure correctly is just as important as selecting the right controls. This presentation examines the physics of noise, how to measure it, who to include in a hearing conservation program, and what controls can be used to reduce the risk.

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Occupational Noise Exposure and Hearing Conservation

  1. 1. Occupational and Environmental Noise Risk Identification and Assessment to Validate Controls and Hearing Conservation Program Presented by: Bernard L Fontaine, Jr., CIH, CSP, Managing Partner, The Windsor Consulting Group, Inc. © 2013 by The Windsor Consulting Group, Inc. All rights reserved. No part of this document may be reproduced or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of The Windsor Consulting Group, Inc.
  2. 2. Occupational Noise Exposure Course Learning Objectives Participants will be able to:  Describe the consequences to health and well being of excessive noise exposure  Understand the measurement (including dosimetry) of noise in relation to current standards  Conduct surveys in the workplace to assess risks from noise Copyright © 2013 The Windsor Consulting Group, Inc.
  3. 3. Occupational Noise Exposure Course Learning Objectives  Awareness of noise hazards in the workplace, at sporting events, and during recreational activity  Direct and indirect effect of noise on people  Identification and assessment of noise risk  Understanding of hearing and hearing loss  Interpret data based on exposure standards  Select possible noise control measures including hearing protection Copyright © 2013 The Windsor Consulting Group, Inc.
  4. 4. Occupational Noise Exposure Topics to be Discussed  Physical properties of sound and human effect  Risk assessment and noise surveys  Analysis and interpretation of noise data  Noise controls – engineering and administrative  Education and training requirements  Audiometry and hearing disorders  Environmental noise sources and effect Copyright © 2013 The Windsor Consulting Group, Inc.
  5. 5. Occupational Noise Exposure WHAT THIS COURSE WILL NOT PROVIDE:  The course is not intended to provide the skills to become an acoustics expert  Select the proper engineering controls based on octave band analysis  Specific instruction on how to operate noise measurement equipment or perform audiometry  Comprehensive discussion on hearing protectors or audiometric determination Copyright © 2013 The Windsor Consulting Group, Inc.
  6. 6. Occupational Noise Exposure WHAT THIS COURSE WILL NOT PROVIDE:  Exposure information on super low, extremely low, and tremendously low frequency used in submarine and mine transmission or man-made noise  Exposure information on high, very high , super high, extremely high, and tremendously high frequency noise from radio and television broadcast, microwave or wave scanners, satellite communications, radio astronomy, ultrafast molecular dynamics, condensed matter physics or amateur radio noise Copyright © 2013 The Windsor Consulting Group, Inc.
  7. 7. What is Noise?  Noise is an unpleasant / unwanted sound  Types of noise 1. Continuous 2. Impulse 3. Impact  Side effects of noise 1. Loss of hearing 2. Physiological/psychological stress 3. Accidents 4. Behavioural effects 5. Negative impact on health Copyright © 2013 The Windsor Consulting Group, Inc.
  8. 8. Occupational Noise Exposure  Loud noises can cause hearing loss  Prolonged exposure to a harmless noise can cause hearing loss  Damage from hearing loss is irreversible  Noise induced hearing loss is preventable  Prevention involves: 1. Noise controls 2. Safe work practices 3. Education Copyright © 2013 The Windsor Consulting Group, Inc.
  9. 9. Occupational Noise Exposure  Occupational hearing loss is the most common workrelated illness in the United States.  Approximately 22 million U.S. workers exposed to hazardous noise levels at work, and an additional 9 million exposed to ototoxic chemicals.  An estimated $242 million is spent annually on worker‟s compensation for hearing loss disability. Copyright © 2013 The Windsor Consulting Group, Inc.
  10. 10. Sound Versus Noise  Sound is a pressure change detectable by the human ear. 1. Pitch (frequency) ranges between 20 to 20,000 Hz 2. Volume ranges between 0 to 140 dB (decibels)  Noise is a type of sound. 1. Carries no information 2. Random 3. Generally described as undesirable or unwanted sound Copyright © 2013 The Windsor Consulting Group, Inc.
  11. 11. Non-Auditory Effects of Noise  Effects cardiovascular system  Effects the nervous system  Interferes with speech and concentration  Causes annoyance, stress, and fatigue  Reduces work efficiency  Lowers morale  Masks warning sounds Copyright © 2013 The Windsor Consulting Group, Inc.
  12. 12. Non-Auditory Effects of Noise  Psychological – can startle, annoy, and disrupt concentration, sleep, or relaxation.  Interference with communication, resulting in interference with job performance and safety.  Physiological – noise induced hearing loss, aural pain, or even nausea. Copyright © 2013 The Windsor Consulting Group, Inc.
  13. 13. The Physics of Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  14. 14. The Physics of Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  15. 15. The Physics of Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  16. 16. Properties of Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  17. 17. Sound Propagation  Sound is a fluctuation in pressure above and below the ambient pressure of a medium that has elasticity and viscosity.  The medium may be a solid, liquid, or gas.  Sound is also defined as the auditory sensation evoked by these oscillations in pressure Copyright © 2013 The Windsor Consulting Group, Inc.
  18. 18. Properties of Sound  Period (T) is the time it takes to complete one full cycle  Frequency (f) is the number of times per second a complete wave passes a point. The number of cycles per second is termed Hertz (Hz).  The period and the frequency are simply related by the following equation: T = 1/f (seconds) Copyright © 2013 The Windsor Consulting Group, Inc.
  19. 19. Properties of Sound  Speed (c) of sound in air is governed by air density and air pressure which in turn relates to the ambient temperature and elevation at or above sea level  At sea level, the speed of sound in air is about 343 m/s  Sound travels about 1 kilometres in 3 seconds (much slower than the speed of light) Copyright © 2013 The Windsor Consulting Group, Inc.
  20. 20. Properties of Sound  Wavelength (λ) is the length of one complete cycle, and is measured in meters (m). It is related to the frequency (f) and speed of sound (c) by: Wavelength (λ) = c/f meters Copyright © 2013 The Windsor Consulting Group, Inc.
  21. 21. Properties of Sound Frequency Wavelength 100 Hz 3 x 107 m 1000 Hz 3 x 106 m 10,000 Hz 3 x 104 m 1 x 106 Hz/1 MHz 300 m 10 MHz 3m 100 MHZ 0.3 m 1,000 MHz 0.3 m Wavelength in air at standard atmospheric conditions Copyright © 2013 The Windsor Consulting Group, Inc.
  22. 22. Properties of Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  23. 23. Properties of Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  24. 24. Properties of Sound  SLMs have electronic circuits which convert the microphone signal to an RMS sound pressure level  The RMS pressure is used because it can be related to the average intensity of the sound or the loudness of the sound  For a pure (simple sine wave) tone it can be shown that the peak pressure and the RMS pressure are related: Prsm = Ppeak = 0.707 x Ppeak √2 For more complex signals, there is no simple relationship between the two Copyright © 2013 The Windsor Consulting Group, Inc.
  25. 25. Properties of Sound  Peak sound is important to measure  In particular for loud impulsive or impact noise, such as gunfire, explosions or punch presses.  The Crest Factor is the ratio of the peak amplitude of a waveform to the RMS value.  Short intense impulses or impacts will have high CF values. Copyright © 2013 The Windsor Consulting Group, Inc.
  26. 26. Properties of Sound  Sound power is defined as the total sound energy generated by the source per unit of time.  Sound power is expressed in units of watts (W) and sound intensity is vector quantity.  It is important to keep in mind that for all practical situations the sound power of a source output is constant regardless of its location (i.e. inside vs. outside).  Conversely, the sound intensity and sound pressure will change as a function of the environment in which it is located. Copyright © 2013 The Windsor Consulting Group, Inc.
  27. 27. Properties of Sound  Sound pressure is expressed as force per unit area, and the unit is the Pascal (Pa).  Keep in mind sound pressure is the “effect” of a disturbance. The actual “cause” of the disturbance, and the resulting reaction effect, is due to sound power measured in decibels decibel = 20log (pa /po ) Copyright © 2013 The Windsor Consulting Group, Inc.
  28. 28. Properties of Sound Sound Pressure Level: Lp 10 log p2 p 2 20 log ref p p ref dB  The “L” in each expression stands for “Level,” and the I, W, and p terms represent intensity, power, and pressure, respectively for hearing at 1000 Hz.  Reference intensity (Iref) = 10-12 w/m2  Reference power (Wref) = 10-12 w  Reference pressure (pref) = 2 x 10-5 N/m2, or 20 µPa Copyright © 2013 The Windsor Consulting Group, Inc.
  29. 29. Properties of Sound A point sound source will radiate sound power evenly in all directions, assuming there are no reflective surfaces present. As the power spreads spherically from its origin, the surface area in increases and so the power per unit area decreases. The total power remains the same, but the enclosing area is increasing, which results in a decrease in the sound intensity. This is known as the inversesquare law. Copyright © 2013 The Windsor Consulting Group, Inc.
  30. 30. Properties of Sound  Sound intensity is based on surface area of sphere = 4 r 2  Therefore at 1 meter from source power will be spread over a sphere whose surface area is 4 x1  At 2 meters this will be 4 x 4 (i.e., 4 times as large and thus the Intensity will be one quarter).  At 3 meters the surface will be 32 = 9 times bigger, thus as the distance from source spreads the energy per unit area diminishes. Copyright © 2013 The Windsor Consulting Group, Inc.
  31. 31. Properties of Sound In air, the expression for each acoustical property is: Sound Intensity Level: Li 10 log Sound Power Level: LW I I ref dB W 10 log dB Wref Copyright © 2013 The Windsor Consulting Group, Inc.
  32. 32. Properties of Sound The decibel scale and use of reference levels  Level is used as understood in the term “water level” i.e. height relative to something else, say the riverbank.  The softest sounds heard about 0.000,000,000,001 watts/m2  Saturn rocket at lift-off is greater than 100,000,000 watts/m2 Copyright © 2013 The Windsor Consulting Group, Inc.
  33. 33. Common Sound Levels Copyright © 2013 The Windsor Consulting Group, Inc.
  34. 34. Common Sound Levels  1 dB change barely perceptible to person with excellent hearing  3 dB difference would be just perceptible to the average listener  5 dB change clearly noticeable  10 dB increase typically perceived as twice as loud. Copyright © 2013 The Windsor Consulting Group, Inc.
  35. 35. Decibel Addition Addition is a simple sum n Lp TOTAL 10 log 10 Lp /10 i i 1 Adding; 89.0dB plus 85.0dB plus 90.0dB 10log [ 1089/10 + 1085/10 + 1090/10] = 93.2 dB Copyright © 2013 The Windsor Consulting Group, Inc.
  36. 36. Decibel Addition Numerical difference between levels LP1 and LP2 (dB) Amount to be added to the higher of LP1 or LP2 (dB)* 0 3.0 1 2.5 2 2.1 3 1.8 4 1.5 5 1.2 6 1.0 7 0.8 8 0.6 9 0.5 10 0.4 greater than10 0.0 for all practical purposes Copyright © 2013 The Windsor Consulting Group, Inc.
  37. 37. Decibel Subtraction This can be done using the equation Lp 10 log 10 L / 10 1 10 L / 10 2 Subtracting; 85 from 90dB. 10log [ 1090/10 - 1085/10] = 88.3dB Alternatively the table for addition of dB can be used in an iterative manner Copyright © 2013 The Windsor Consulting Group, Inc.
  38. 38. Average Sound Level Pressure The equation to determine the average sound level for a number of measurements of a source is: Lp 1 10 log n n 10 Lp /10 i i 1 Averaging; 81, 86, 82 and 84dB. 10log 1/4[ 1081/10 + 1086/10 + 1082/10 + 1084/10] = 83.7dB Copyright © 2013 The Windsor Consulting Group, Inc.
  39. 39. Directivity of Sound Propagation Copyright © 2013 The Windsor Consulting Group, Inc.
  40. 40. Frequency Characteristics of Sound  Workplace sounds are not simple sine waves  Broad spectrum of frequencies can to be divided into smaller bandwidths to assist the analysis for risk assessment, noise control, evaluation of hearing protection etc.  The sound level meter may contain a filter measure selected bandwidths of concern or a frequency analyser can be used. Most common bandwidths are 1. octave bands 2. third octave bands Copyright © 2013 The Windsor Consulting Group, Inc.
  41. 41. Overall Sound Level by Frequency Frequency, (Hz) 63 125 250 500 1000 2000 4000 SPL (dB re 20µPa) 95 72 85 80 86 82 79 Rearranging in ascending order 72 79 80 82 85 86 95 Difference 7 0.2 1 0.5 2 4.9 Add 0.8 3 2.5 2.5 2.1 1.2 Cum. level dB 79.8 83 85.5 88 90.1 96.2 Copyright © 2013 The Windsor Consulting Group, Inc.
  42. 42. Octave Frequency Analysis Copyright © 2013 The Windsor Consulting Group, Inc.
  43. 43. Weighted Sound Levels  Microphones and human ears have a different frequency response.  Several weighting networks (or frequency filters) were designed to make the SLM respond to frequency like our ear.  The accepted frequency for occupational and environmental noise is the A weighting.  Common weightings are A, C, Z and linear Copyright © 2013 The Windsor Consulting Group, Inc.
  44. 44. Weighted Sound Levels Frequency, Hz A weighting C weighting Z weighting 16 -56.7 -8.5 31.5 -39.4 -3.0 63 -26.2 -0.8 125 -16.1 -0.2 250 - 8.6 -0.0 Flat 500 - 3.2 -0.0 from10Hz 1000 0 0 to 20kHz 2000 + 1.2 -0.2 4000 + 1.0 -0.8 8000 - 1.1 -3.0 16000 - 6.6 -8.5 Copyright © 2013 The Windsor Consulting Group, Inc.
  45. 45. Weighted Sound Levels Copyright © 2013 The Windsor Consulting Group, Inc.
  46. 46. Equal Loudness Contours Copyright © 2013 The Windsor Consulting Group, Inc.
  47. 47. Human Audible Range of Hearing  The normal range in human hearing is 20 Hz to 20,000 Hz. Sound at higher frequencies is called Ultrasound whereas lower frequencies is Infrasound  Human sensitivity to hearing based on configuration of the ear is greatest from 2,000 to 5,000 Hz  Minimum audible field in the most sensitive range is close to 0 dB, which is 20 µPa  This is the principal reason 20 µPa is designated the international reference pressure for determining SPL Copyright © 2013 The Windsor Consulting Group, Inc.
  48. 48. Time-Varying Noise Sources  Compressors, fans, electric motors etc. generally produce sounds that are continuous or steady-state.  A steady-state sound remains relatively constant in time, varying by less than +/- 3 dB  But what if they cycle off and on?  Sources with levels that fluctuate more than ± 3 dB are generally classified as variable noise sources like a brake press  Which part of the noise should we measure? Copyright © 2013 The Windsor Consulting Group, Inc.
  49. 49. Time-Varying Noise Sources Copyright © 2013 The Windsor Consulting Group, Inc.
  50. 50. Time-Varying Noise Sources  Another type of time varying noise is that produced as an impact or impulse.  Impact sound can be generated by the solid collision between two objects, such as hammering, dropped objects, a door slamming shut, metal-to-metal impacts, etc. or by explosions such as gun fire or explosive tools.  Impulse sound is defined as an event having an exponential rise time constant of 35 milliseconds, and an asymmetric decay time constant of 1.5 seconds. Copyright © 2013 The Windsor Consulting Group, Inc.
  51. 51. Anatomy of the Human Ear Copyright © 2013 The Windsor Consulting Group, Inc.
  52. 52. Anatomy of the Human Ear Copyright © 2013 The Windsor Consulting Group, Inc.
  53. 53. Healthy Cochlea The cilia ( sensory hairs) appear normal Copyright © 2013 The Windsor Consulting Group, Inc.
  54. 54. Damaged Cochlea Loss of cilia from noise exposure Copyright © 2013 The Windsor Consulting Group, Inc.
  55. 55. Threshold Shifts  Temporary Threshold Shifts (TTS) hearing returns to normal after noise exposure  Permanent Threshold Shifts (PTS) repeated noise exposure without a return to normal  Standard Threshold Shifts (STS) > 10 dB average loss in 2000, 3000, or 4000 Hz in either ear Copyright © 2013 The Windsor Consulting Group, Inc.
  56. 56. Noise and Acoustics Hazardous noise exposures can occur On the Job Off the Job Copyright © 2013 The Windsor Consulting Group, Inc.
  57. 57. Noise and Acoustics  Noise-Induced Hearing Loss 1. Causes no pain 2. Causes no visible trauma 3. Leaves no visible scars 4. Is unnoticeable in its earliest stages 5. Accumulates with each overexposure 6. Takes years to notice a change Is Permanent + 100% Preventable Copyright © 2013 The Windsor Consulting Group, Inc.
  58. 58. Noise and Acoustics Factors Affecting Hearing Loss 1. Noise Intensity or Sound Pressure 2. Frequency or Pitch 3. Length of Daily Exposure 4. Duration of Exposure in Years 5. Individual Susceptibility 6. Other Factors (disease, genetics, lifestyle, medication, age, etc.) Copyright © 2013 The Windsor Consulting Group, Inc.
  59. 59. Noise and Acoustics  Worker‟s Compensation  In many countries, excessive noise is the biggest compensable occupational hazard.  Cost of NIHL to developed countries ranges from 0.2 to 2% of its GDP.  NIHL is on the rise globally. (Source: WHO) Copyright © 2013 The Windsor Consulting Group, Inc.
  60. 60. Noise and Acoustics  United States Statistics  Most common occupational injury in the United States. 22 million US workers are exposed to hazardous noise at work on a daily basis.  Approx. 8 million Americans suffer from NIHL. (Source: NIOSH, 2009) Copyright © 2013 The Windsor Consulting Group, Inc.
  61. 61. Noise and Acoustics Copyright © 2013 The Windsor Consulting Group, Inc.
  62. 62. Noise Risk Register Copyright © 2013 The Windsor Consulting Group, Inc.
  63. 63. Noise Risk Assessment Copyright © 2013 The Windsor Consulting Group, Inc.
  64. 64. Noise Risk Register by Job Title Copyright © 2013 The Windsor Consulting Group, Inc.
  65. 65. Noise Risk Register by Job Title Rank Order Noise Risks Copyright © 2013 The Windsor Consulting Group, Inc.
  66. 66. Noise Risk Register by Job Title Chipping Concrete Floor 96 dBA (TWA) at 4.5 hours Copyright © 2013 The Windsor Consulting Group, Inc.
  67. 67. Noise Risk Register by Job Title Sandblasting - 125 dBA (4 hour sample) Inside hood - 109 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  68. 68. Noise Risk Register by Job Title 36" Wall Saw - 100 dBA (4.5 hour sample) Copyright © 2013 The Windsor Consulting Group, Inc.
  69. 69. Noise Risk Management  What is a “safe” level?  There is no simple answer as to what constitutes a “safe” noise exposure limit.  The answer involves the intricate and diverse variables associated with an person‟s susceptibility to noise and characteristics and magnitude of the noise exposure.  Hearing conservation measures include: • Noise exposure criteria of 85 dBA for the 8-hour workday AND • Peak levels should never exceed 140 dBC. Copyright © 2013 The Windsor Consulting Group, Inc.
  70. 70. OSHA Noise Standard Program Strategy – Noise and Hearing Conservation Noise Exposure Program – 90 dBA 8 hour TWA (Equivalent Exposure Concept) Hearing Conservation Program – 85 dBA 8 hour TWA TWA- Time Weighted Average Copyright © 2013 The Windsor Consulting Group, Inc.
  71. 71. Table G-16 - Permissible Noise Exposures Duration per day, hours Sound level dBA slow response 8 90 6 92 4 95 3 97 2 100 1½ 102 1 105 ½ 110 ¼ or less 115 Footnote(1) When the daily noise exposure is composed of two or more periods of noise exposure of different levels, their combined effect should be considered, rather than the individual effect of each. If the sum of the following fractions: C(1)/T(1) + C(2)/T(2) C(n)/T(n) exceeds unity, then, the mixed exposure should be considered to exceed the limit value. Cn indicates the total time of exposure at a specified noise level, and Tn indicates the total time of exposure permitted at that level. Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level. Copyright © 2013 The Windsor Consulting Group, Inc.
  72. 72. Noise Action Level  Action Level (AL) = 85 dBA for a 8-hour TWA  Determined without regard to hearing protector attenuation  Hearing Conservation Program (HCP) required when noise exposures equal or exceed the action level  Monitoring program implemented when noise exposures equal or exceed the action level Copyright © 2013 The Windsor Consulting Group, Inc.
  73. 73. Measurement of Noise Loudness 170 dB Jet airliner 130 dB Pneumatic chipping and riveting 120 dB Riveting hammer 110 dB Shouting loudly or automatic punch press 90 dB Construction site pneumatic drilling 70 dB Street sounds 38 dB Quiet bedroom This is a logarithmic scale – an increase of 1dB means about 30% more noise Copyright © 2013 The Windsor Consulting Group, Inc.
  74. 74. Exposure Level vs. Duration 140 120 100 80 Decibel 60 - Noise Control Program 40 - Hearing Conservation 20 0 2 4 6 8 Exposure Duration (Hours) Copyright © 2013 The Windsor Consulting Group, Inc.
  75. 75. Noise Measuring Equipment  Sound Level Meters (SLM) Continuous on-mobile sources  Noise Dosimeters Mobile various sources Copyright © 2013 The Windsor Consulting Group, Inc.
  76. 76. Noise Measuring Equipment Copyright © 2013 The Windsor Consulting Group, Inc.
  77. 77. Noise Measuring Equipment  There are two types or classes of SLMs established by International Standards Class 1 - precision meter, and Class 2 - general purpose instrument with lower performance specifications than Class 1  Measurements are undertaken with the appropriate class of SLM Copyright © 2013 The Windsor Consulting Group, Inc.
  78. 78. Noise Measuring Equipment  There are three types of microphones 1. Random incidence microphones, (omnidirectional) 2. Direct incidence microphones, (free-field) 3. Pressure microphones (pressure-response)  Most commonly used is the random incidence or omnidirectional microphone Copyright © 2013 The Windsor Consulting Group, Inc.
  79. 79. Noise Measuring Equipment Copyright © 2013 The Windsor Consulting Group, Inc.
  80. 80. Noise Measuring Equipment Copyright © 2013 The Windsor Consulting Group, Inc.
  81. 81. SLM and Octave Band Analyzer Copyright © 2013 The Windsor Consulting Group, Inc.
  82. 82. Noise Measuring Equipment Frequency analysis 1/3 octave-band spectral data for the sound levels generated by an internal combustion engine. Copyright © 2013 The Windsor Consulting Group, Inc.
  83. 83. Noise Measuring Equipment  A noise dosimeter is an SLM designed to measure a worker‟s noise exposure over a period of time.  The output is available as both noise dose and noise exposure.  Noise exposure may be shown as an Leq,8h, LEX,8H, or TWA.  TWA - Time weighted average - implies an eighthour (8-hour) average. Copyright © 2013 The Windsor Consulting Group, Inc.
  84. 84. 1/3 Octave Band Analyzer Copyright © 2013 The Windsor Consulting Group, Inc.
  85. 85. Case Study: Noise Monitoring Case Study: Consider a worker who undertakes these work tasks: 1. Use planer with noise level at the ear of 102 dBA for 0.5 hours 2. Use saw with noise level at the ear of 98 dBA for 4 hours 3. Use of drill with noise level at the ear of 89 dBA for 2.5 hours 4. Hammering with noise level at the ear of 92 dBA for 2 hours Copyright © 2013 The Windsor Consulting Group, Inc.
  86. 86. OSHA Maximum Exposure Time Leq Time Leq Time Leq Time Leq Time 80 32.0 90 8.0 100 2.0 110 0.50 81 27.9 91 7.0 101 1.7 111 0.44 82 24.3 92 6.1 102 1.5 112 0.38 83 21.1 93 5.3 103 1.3 113 0.33 84 18.4 94 4.6 104 1.1 114 0.29 85 16.0 95 4.0 105 1.0 115 0.25 86 13.9 96 3.5 106 0.87 116 0.22 87 12.1 97 3.0 107 0.76 117 0.19 88 10.6 98 2.6 108 0.66 118 0.16 89 9.2 99 2.3 109 0.57 119 0.14 Copyright © 2013 The Windsor Consulting Group, Inc.
  87. 87. Noise Exposure Monitoring Calculate dose using the formula: Dose = 100 x (C1/T1 + C2/T2 + C3/T3 + ... + Cn/Tn) where: Cn is the time spent doing each work task and allowable Tn = 8 2(L-90)/5  Calculated noise dose of planer at 102 dB for 0.5 hours, sawing at 98 dBA for 4 hours; drilling at 89 dBA for 2.5 hours; and hammering 92 dBA for 2 hours = 247.1% or 96.5 dBA for 8-hour TWA. Copyright © 2013 The Windsor Consulting Group, Inc.
  88. 88. Noise Exposure Monitoring Source SPL,dBA Time Hrs. OSHA max PEL 8- Hrs. OSHA max PEL 9-Hrs Planar 102 0.5 1.5 ---- Saw 98 4 2.6 ---- Drill 89 2.5 9.2 ---- Hammer 92 2 6.1 ---- 9.0 Over maximum 8-hours Total LAeq,8h 97 dBA 3.0 Hrs. (180 mins.) 2.7 hrs. (160 mins) Copyright © 2013 The Windsor Consulting Group, Inc.
  89. 89. Noise Risk Assessment No. Work Process or Operation LAeqT Peak Risk Assessment Complies with OSHA Requirements 1 Honda Bike 67 - Very Low YES 2 Cushman Truck 75 103 Low YES 3 Cushman Sprayer 76 102 Low YES 4 Quad Runner 72 101 Low YES 5 Mower Reelmaster 83 102 Low YES 6 Mower Ransomes 83 102 Low YES 7 Mower John Deere 86 105 Moderate NO, if exposure exceeds 6 hrs. 36 min. 8 Mower John Deere 90 115 High NO, if exposure exceeds 2 hrs. 32 min. 9 Blower Echo 94 108 Very High NO, if exposure exceeds 1 hr. 4 min. 10 Whipper Snipper Kawasaki 98 113 Extremely High NO, if exposure exceeds 25 min. Copyright © 2013 The Windsor Consulting Group, Inc.
  90. 90. Noise Risk Assessment Copyright © 2013 The Windsor Consulting Group, Inc.
  91. 91. Noise Risk Assessment BENCH GRINDER ENGINEERING SHOP APPALACHIAN FRUIT RESEARCH STA. Running (no load) Running (with load) 76.3 dBA 92.1 dBA ANGLE GRINDER ENGINEERING SHOP APPALACHIAN FRUIT RESEARCH STA. Running (no load) 101.4 dBA Running (with load) 106.2 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  92. 92. Noise Risk Assessment SCREW CHILLER QUARANTINE GREENHOUSE FOREIGN DISEASE / WEED SCI. RES. UNIT 102.4 dBA WELL PUMPS WATER TREATMENT BUILDING APPALACHIAN FRUIT RESEARCH STA. 82.8 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  93. 93. Noise Risk Assessment RADIAL ARM SAW ENGINEERING SHOP APPALACHIAN FARMING SYSTEMS RESEARCH CENTER Running (no load) Running (with load) 81.5 dBA 90.5 dBA DRILL PRESS ENGINEERING SHOP APPALACHIAN FARMING SYSTEMS RESEARCH CENTER Running (no load) Running (with load) 88.7 dBA 93.8 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  94. 94. Noise Risk Assessment GRINDING HOODS APPALACHIAN FARMING SYSTEMS RESEARCH CENTER 89.3 dBA AIR HANDLER QUARANTINE GREENHOUSE FOREIGN DISEASE / WEED SCI. RES. UNIT 87.8 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  95. 95. Noise Risk Assessment FRUIT GRADER / SORTER FARM CENTER COMPLEX APPALACHIAN FRUIT RESEARCH STA. 91.1 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  96. 96. Statistical Risk Modelling Predicted Noise Exposure Winter Schedule 1998 + Ballet All Performances 100 95 85 80 75 Performance weekly average 29-Oct 19-Oct 09-Oct 29-Sep 19-Sep 09-Sep 30-Aug 20-Aug 10-Aug 31-Jul 21-Jul 11-Jul 01-Jul 21-Jun 11-Jun 01-Jun 23-May 13-May 03-May 23-Apr 13-Apr 03-Apr 24-Mar 14-Mar 05-Mar 23-Feb 13-Feb 03-Feb 24-Jan 14-Jan 04-Jan 70 25-Dec dB(A) 90 Long term Exposure Copyright © 2013 The Windsor Consulting Group, Inc.
  97. 97. Personnel Notification of Results  The employer shall notify each employee exposed at or above 85 dBA of the noise monitoring results. Copyright © 2013 The Windsor Consulting Group, Inc.
  98. 98. Day-Night Environmental Test WHO guideline for night noise (Lnight, outside) is 40 dB (2002. Copyright © 2013 The Windsor Consulting Group, Inc.
  99. 99. Environmental Exposure Model Comparison of Day/Evening/Night Exposures Guidance for Average Background Noise Levels, LA90,T Type of Area WHO interim guideline for night noise (Lnight, outside) is 55 dB (2002). Time of Day Day (700-1800) Evening (18002200) Night (2200700) Rural (i.e., negligible transportation) 40 35 30 Semi rural and low density transportation 45 40 35 50 45 40 55 50 45 Borders of industrial areas 60 55 50 Within industrial areas 65 60 55 Near some commerce or industry Near dense transportation Copyright © 2013 The Windsor Consulting Group, Inc.
  100. 100. Environmental Exposure Model Copyright © 2013 The Windsor Consulting Group, Inc.
  101. 101. Inversion of Temperature and Sound Daytime Night and temperature inversion Copyright © 2013 The Windsor Consulting Group, Inc.
  102. 102. Wind Direction and Sound Copyright © 2013 The Windsor Consulting Group, Inc.
  103. 103. Noise Engineering Controls       Enclosures Sound barriers Complete enclosure Sound proof cabs Mufflers Equipment and exhaust Copyright © 2013 The Windsor Consulting Group, Inc.
  104. 104. Sound Contour Mapping Planograms Copyright © 2013 The Windsor Consulting Group, Inc.
  105. 105. Sound Contour Mapping Planograms Copyright © 2013 The Windsor Consulting Group, Inc.
  106. 106. Exposure Modelling Risk Copyright © 2013 The Windsor Consulting Group, Inc.
  107. 107. Exposure Modelling Risk Copyright © 2013 The Windsor Consulting Group, Inc.
  108. 108. Exposure Modelling Risk Copyright © 2013 The Windsor Consulting Group, Inc.
  109. 109. Exposure Modelling Risk Copyright © 2013 The Windsor Consulting Group, Inc.
  110. 110. Exposure Modelling Risk Copyright © 2013 The Windsor Consulting Group, Inc.
  111. 111. Noise and Acoustics Hierarchy of Controls ENGINEERING CONTROLS  Buy Quiet  Vibration Pads  Enclosures  Barriers  Isolation ADMINISTRATIVE CONTROLS  Rotate Workers  Extended Breaks  2nd/3rd Shift PERSONAL PROTECTIVE EQUIPMENT Copyright © 2013 The Windsor Consulting Group, Inc.
  112. 112. Noise Engineering Controls Flanking Absorbed NOISE Copyright © 2013 The Windsor Consulting Group, Inc.
  113. 113. Noise Engineering Controls Copyright © 2013 The Windsor Consulting Group, Inc.
  114. 114. Sound Transmission Loss Multiple layer panels combine a sound absorption material with a high transmission loss material to form a composite system. Can be sound absorbing material on one side or a complex „sandwich” panel with a number of layers Copyright © 2013 The Windsor Consulting Group, Inc.
  115. 115. Sound Transmission Loss Copyright © 2013 The Windsor Consulting Group, Inc.
  116. 116. Administrative Controls  If engineering controls are not feasible, administrative controls should be considered:  Rotate employees to reduce exposure  Limit number of at-risk workers  Modify or upgrade existing machinery  Specify noise limit on new equipment  Maintain and repair equipment/machinery  Post signs for workers to use hearing protection  Report noisy equipment/machinery to supervisor Copyright © 2013 The Windsor Consulting Group, Inc.
  117. 117. Types of Hearing Protection  There are three types of hearing protection – ear muffs, earplugs and ear caps.  Ear muffs and earplugs provide about equal protection, ear caps somewhat less. Earmuffs Earplugs Ear caps Copyright © 2013 The Windsor Consulting Group, Inc.
  118. 118. Hearing Protection Selection and Use  Ensure it is suitable for the job  Make sure it hearing device does not interfere with other safety equipment  Discard disposal ear plugs  Regular maintain ear muffs and ear channel caps  Home-made protectors don‟t work (e.g., cotton, wool)  Use hearing protection with communication devices Copyright © 2013 The Windsor Consulting Group, Inc.
  119. 119. Noise and Acoustics  Overprotection/Underprotection 20-25% workers exposed between 80-90 dB will still get NIHL. While HPD use is mandatory at 90 dB, you should protect to at least 85 dB. Avoid overprotection – protected levels below 65-70 dB can create additional safety risk. Copyright © 2013 The Windsor Consulting Group, Inc.
  120. 120. Sports and Recreational Activities Protect your hearing off the job too……  Loud music  Personal stereos  Car entertainment  Electronic devices  Lawn mowers  Chain saws  Fire arms and fireworks  Sporting events  Racing  Highway driving with vehicle windows open Copyright © 2013 The Windsor Consulting Group, Inc.
  121. 121. Hearing Protector Attenuation  For overexposed employees and those at-risk of being over exposed  At a minimum attenuate < 90 dBA 8-hr TWA  For workers with an STS attenuate < 85 dBA 8-hr TWA  Whenever noise exposures increase risk to more workers exposed, change in operation, process or machinery  Reevaluated to determine adequacy of the selected devices Copyright © 2013 The Windsor Consulting Group, Inc.
  122. 122. Noise Reduction Rating (NRR)  Defined as the maximum number of decibels (dB) that the hearing protector will reduce the sound level when worn.  NRR must be on the hearing protector package.  NRR example for A-weighted data Estimated exposure (dBA) = TWA (dBA) - (NRR - 7) Example (plugs or muffs): TWA = 109 dBA, NRR= 29 109 - (29-7) = 109 dBA - 22dB = 87 dBA Copyright © 2013 The Windsor Consulting Group, Inc.
  123. 123. Noise Reduction Rating 80th % Minimallytrained Current NRR Label 20th % Proficient Users Mock-up of New Label Copyright © 2013 The Windsor Consulting Group, Inc.
  124. 124. Proper Use of Hearing Protection  It takes just a few minutes of unprotected exposure at noise above 115 decibels to risk hearing damage.  Earplugs not well inserted into the ear canal will not provide complete protection.  Likewise, earmuffs not snug against the head will “leak” noise into the ear. Copyright © 2013 The Windsor Consulting Group, Inc.
  125. 125. Audiometric Testing Program  Baseline audiometric test taken when noise exposures equal or exceed the action level.  A qualified person performs the hearing test, usually an audiologist.  Results interpreted by qualified person  Audiometer checked before each use and calibrated acoustically annually  Records of calibrations required Copyright © 2013 The Windsor Consulting Group, Inc.
  126. 126. Audiometric Testing  Provided at no cost to the employee  Baseline audiogram within 6 months of first noise exposure at or above action level  For mobile test van, < 12 months  Provided initially and annually  Allowance for aging  STS notification Copyright © 2013 The Windsor Consulting Group, Inc.
  127. 127. Example of Audiogram Baseline Annual Copyright © 2013 The Windsor Consulting Group, Inc.
  128. 128. STS Notification  Recall standard threshold shift (STS) definition:  > 10 dB avg. loss 2kHz – 4 kHz  Employer may retest within 30 days to verify the STS.  Audiologist shall determine need for further evaluation.  Employer shall notify the affected employee of the STS in writing within 21 days. Copyright © 2013 The Windsor Consulting Group, Inc.
  129. 129. Audiogram with Hearing Loss 2KHz 3KHz 4KHz Copyright © 2013 The Windsor Consulting Group, Inc.
  130. 130. Personnel Training  Training is required for employees who are exposed to noise at or above 8 hr. TWA of 85 dB.  Topics must include: 1. Effects of noise on hearing 2. Purpose of hearing protectors 3. Advantages and disadvantages of hearing protectors 4. Attenuation of hearing protectors 5. Instructions on selection, fitting, use, and care of hearing protectors 6. Purpose of audiometric testing Copyright © 2013 The Windsor Consulting Group, Inc.
  131. 131. Post the Standard  Make available to affected employees or their representatives copies of the standard.  Post a copy of the standard in the workplace Copyright © 2013 The Windsor Consulting Group, Inc.
  132. 132. Recordkeeping  Permanent hearing loss is a OSHA recordable illness  Provide access to employee exposure monitoring and audiometric data  If business terminates. transfer records to successor or forward documents to NIOSH  Otherwise, keep noise measurements: > 2 years  Audiometric tests > employment duration: 1. Name, job classification and dBA-TWA 2. Date, examiner‟s name and calibration date 3. Background measurements of audiometric test room Copyright © 2013 The Windsor Consulting Group, Inc.
  133. 133. Don‟t Take Noise for Granted!  Hearing damage creeps up on you  Hearing loss is easily preventable  Once it has happened, there may be no cure Copyright © 2013 The Windsor Consulting Group, Inc.
  134. 134. Contact: Bernard L Fontaine, Jr., CIH, CSP The Windsor Consulting Group, Inc. Email: windsgroup@aol.com Tel: 1+ 732.221.5687

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