GTK210 Lecture 4 OHL Dr.Nazrey PDF
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Universiti Sains Malaysia
2024
Hj. Mohd Nazhari Bin Hj. Mohd Nawi
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Summary
This document is a lecture on Occupational Hearing Loss (OHL). It covers various aspects of noise and its effects, as well as terminology related to hearing loss. The lecture is delivered by Dr. Nazhari from Universiti Sains Malaysia.
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GTK210=GTA406=2024-2025 DR.NAZREY 1 OCCUPATIONAL HEARING LOSS (OHL) DR. HJ. MOHD NAZHARI BIN HJ. MOHD NAWI MD, MCommMed (Occupational), OHD, CMIA, MRO, CHRA Medical Specialist (Public Health / Occupational Health) Senior Medical Lecturer Environmental / Occupational Health Schoo...
GTK210=GTA406=2024-2025 DR.NAZREY 1 OCCUPATIONAL HEARING LOSS (OHL) DR. HJ. MOHD NAZHARI BIN HJ. MOHD NAWI MD, MCommMed (Occupational), OHD, CMIA, MRO, CHRA Medical Specialist (Public Health / Occupational Health) Senior Medical Lecturer Environmental / Occupational Health School Of Health Sciences Universiti Sains Malaysia Certified Occupational Health Doctor Certified Medical Impairment Assessor GTK210=GTA406=2024-2025 DR.NAZREY Certified Medical Review Officer 2 Certified Chemical Health Risk Assessor THE PROBLEM: I tell ya…. Noise Induced Hearing Loss don’t get no respect…….. GTK210=GTA406=2024-2025 DR.NAZREY 3 INTRODUCTION 2nd most common form of Sensori-Neural hearing deficit after Presbycusis. 100% preventable. GTK210=GTA406=2024-2025 DR.NAZREY 4 PERKESO Akta Keselamatan Sosial Pekerja 1969, Peraturan- Peraturan (Am) Keselamatan Sosial Pekerja 1971 Loss of hearing in one ear 30% loss of earning Total loss of hearing 60% loss of working capacity GTK210=GTA406=2024-2025 DR.NAZREY 5 EX-GRATIA Skim Ex-Gratia Bencana Kerja Bagi Anggota Perkhidmatan Awam 2013 Loss of hearing in one ear 20% loss of earning Total loss of hearing 100% loss of working capacity GTK210=GTA406=2024-2025 DR.NAZREY 6 Noise : many sources, exposed hours, variable levels DYNAMIC GTK210=GTA406=2024-2025 DR.NAZREY 7 GTK210=GTA406=2024-2025 DR.NAZREY 8 2000 2005 GTK210=GTA406=2024-2025 DR.NAZREY 9 2019 2021 GTK210=GTA406=2024-2025 DR.NAZREY 10 2024 GTK210=GTA406=2024-2025 DR.NAZREY 11 FUNDAMENTAL OF NOISE GTK210=GTA406=2024-2025 DR.NAZREY 12 TERMINOLOGY SOUND A pressure variation in air, water or some other medium that can be detected by the human ear NOISE Any unwanted or desirable sound HAZARDOUS NOISE Any sound for which any combination of frequency, intensity or duration is capable of causing permanent hearing loss GTK210=GTA406=2024-2025 DR.NAZREY 13 NOISE DOSE Noise exposure expressed as a % of allowable daily exposure EXCHANGE RATE The relationship between intensity and dose OSHA use 5-dB but NIOSH use 3-dB And if intensity increased by 5-dB and 3-dB, dose of exposure will be DOUBLE GTK210=GTA406=2024-2025 DR.NAZREY 14 HEARING LOSS Is a physiological, psychological or anatomical abnormality affecting the ability to accurately receive, interpret or process sound waves Hearing threshold at or more than 25 dB in any frequency HEARING IMPAIRMENT Average permanent hearing threshold at 500 Hz, 1000 Hz, 2000 Hz and 3000 Hz shifted 25 dB or more from reference GTK210=GTA406=2024-2025 DR.NAZREY 15 STANDARD THRESHOLD SHIFT An average shift of more than 10 dB at frequencies of 2000, 3000, 4000 Hz relative to the baseline audiogram in either ear Pathophysiology Temporary Threshold Shift : Hair cell fatigue Permanent Threshold Shift : Hair cell atrophy Temporary Threshold Shift : Re-test within 3 months Used to trigger additional audiometric testing and related follow up GTK210=GTA406=2024-2025 DR.NAZREY 16 SOUND WAVE Occur in media with mass Typical Media Air Water GTK210=GTA406=2024-2025 DR.NAZREY 17 SOUND COMPONENT Frequency Hertz (Hz) or cycles per second Amplitude or Loudness or Intensity Decibels (dB) Duration GTK210=GTA406=2024-2025 DR.NAZREY 18 FREQUENCY Number of times per second a vibrating body (air) completes one cycle of motion. One Cycle Frequency A B > Frequency A GTK210=GTA406=2024-2025 DR.NAZREY 19 Frequency B FREQUENCY Number of sound waves produce by a noise source passing a given points per second Measured in Hertz (Hz) or cycle per second Perceived by listener as pitch Human voice has range of 200 Hz to 4000 Hz Normal hearing – 10 Hz to 2000 Hz GTK210=GTA406=2024-2025 DR.NAZREY 20 AMPLITUDE = LOUDNESS = INTENSITY The overall ability of a source to emit sound The quantity of sound produced at a given location away from the source x A Intensity B > Amplitude A GTK210=GTA406=2024-2025 DR.NAZREY 21 Amplitude B AMPLITUDE = LOUDNESS = INTENSITY Measured in decibel (dB), is the unit of sound pressure level (log scale) Measure the amplitude of the pressure changes that produce sound Perceived by listener as loudness Loudness of sound or the pressure it exerts through the ear dB scale of the range of human hearing much smaller and easier for occupational hygiene measurements and calculations 0 dB - 120 dB GTK210=GTA406=2024-2025 DR.NAZREY 22 DURATION Impulsive Type -Impact and impulse noises -Step rise in sound level to high peak then quickly fades Continuous type -Non-impulsive noises GTK210=GTA406=2024-2025 DR.NAZREY 23 GENERAL CLASSES OF NOISE Continuous noise Intermittent-Steady noise Intermittent-Fluctuating noise Fluctuating noise Impact or Impulse noise GTK210=GTA406=2024-2025 DR.NAZREY 24 STEADY CONTINUOUS NOISE Noise which has negligibly small fluctuations of sound level within the period of observation SOUND LEVEL Varying less than 3 dB GTK210=GTA406=2024-2025 DR.NAZREY TIME 25 INTERMITTENT-STEADY NOISE < 3 dB SOUND LEVEL < 3 dB TIME GTK210=GTA406=2024-2025 DR.NAZREY 26 INTERMITTENT-FLUCTUATING NOISE > 3 dB SOUND LEVEL GTK210=GTA406=2024-2025 DR.NAZREY 27 TIME FLUCTUATING NOISE > 3 dB SOUND LEVEL > 3 dB GTK210=GTA406=2024-2025 DR.NAZREY 28 TIME IMPUSIVE NOISE Rapid rise ( 1 second < 0.5 second TIME GTK210=GTA406=2024-2025 DR.NAZREY 29 SOUND PRESSURE LEVEL (SPL) Sound pressure (LP) measured in decibels (dB) due to wide range in audible sound pressure. P LP = 20 LOG PO P = Measured sound pressure PO = Reference pressure (in air 0.00002 N/m2 or 20 Micropascals) GTK210=GTA406=2024-2025 DR.NAZREY 30 Decibel (dB) is the unit of sound pressure level (logarithmic scale / log scale) dB scale of the range of human hearing much smaller and easier for occupational hygiene measurements and calculations 0 dB - 120 dB Most environmental noise includes a wide bands of frequency are measured through the ‘A’ filter in the sound level meter So resulting average = constant noise level Expressed in db(A), decibel-A-weighted Unit of measurement of sound level corrected to the A-weighted scale using a reference level of 20 micropascals GTK210=GTA406=2024-2025 DR.NAZREY 31 Examples of Different SPLs and Frequencies Sounds are for comparisons only and not actual dB levels 1 KHz @ 94 dB 1 KHz @ 114 dB 250 Hz @114 dB GTK210=GTA406=2024-2025 DR.NAZREY 32 A, B, C, Weighting Scales 5 A 0 -5 B and C Relative Response = Decibels C -10 -15 B -20 Frequency Frequency Responses Responses -25 for for SLM SLM Weighting Weighting Characteristics Characteristics -30 A -35 -40 -45 Frequency = Hz -50 20 50 100 200 500 1000 2000 5000 10,000 20,000 · A-weighting attenuates low frequency noise · Mimics how the human ear responds to noise GTK210=GTA406=2024-2025 DR.NAZREY 34 A-WEIGHTED SCALE Simulates the sensitivity of the human ear at moderate sound levels Correlation between dB(A) and potential loss of hearing from prolonged noise exposure Used as basis for occupational noise exposure control programs GTK210=GTA406=2024-2025 DR.NAZREY 35 TYPICAL A-WEIGHTED SOUND LEVELS Sound Source A-Weighted And Sound Pressure Measurement Location Level Pneumatic chipper at operator’s ear 120 dB(A) Accelerating motorcycle at 1 m 110 dB(A) Shouting at 1.5 m 100 dB(A) Loud lawnmower at operator’s ear 90 dB(A) Freeway traffic at 50 m 70 dB(A) Normal male voice at 1 m 60 dB(A) Copying machine at 2 m 50 dB(A) Air conditioning in auditorium 30 dB(A) Quiet natural area with no wind 20 dB(A) Anechoic sound testing chamber 10 dB(A) The Occupational Environment -- Its Evaluation and Control GTK210=GTA406=2024-2025 DR.NAZREY 36 SOUND INTENSITY LEVEL Decibel level Source 140 Threshold of pain,gunshot,siren at 100 feet 135 Jet take off,amplified music 120 Chain saw,jack hammer,snowmobile 100 Tractor,farm equipment,power saw 90 OSHA limit 85 Inside acoustically insulated tractor cab 75 Average radio, vacuum cleaner 60 Normal conversation 45 Rustling leaves, soft music 30 Whisper 15 Threshold of hearing 0 Acute threshold of hearing-weakest sound GTK210=GTA406=2024-2025 DR.NAZREY 37 INTENSITY LEVEL FOR COMMON TOOLS Mortising Orb. Sand. Table Saw Task/Tool Planer Belt Sander Router Metal Shear Hand Drill Circular Saw Tile Saw Impact Wrench Miter Saw Chop Saw Chain Saw GTK210=GTA406=2024-2025 Hammer Drill DR.NAZREY 38 75 80 85 90 95 100 105 110 115 The Average 25 Year Old Carpenter Has 50 Year Old Ears!!!! GTK210=GTA406=2024-2025 DR.NAZREY 39 HEARING LOSS GTK210=GTA406=2024-2025 DR.NAZREY 40 TYPES OF HEARING LOSS 1. CONDUCTIVE HEARING LOSS Injury or medical condition affects the outer ear or middle ear Usually reversible Frequent causes : Otitis Externa, Otitis Media, Tumor 2. SENSORY-NEURAL HEARING LOSS Injury or medical condition affects the inner ear to the brain (Auditory Nerves) Majority are PERMENANT BUT PREVENTABLE Frequent causes : Presbycusis, Mumps, Ototoxic Medication and Head Injuries GTK210=GTA406=2024-2025 DR.NAZREY 41 TYPES OF OCCUPATIONAL HEARING LOSS 1. NOISE INDUCED HEARING LOSS 2. ACOUSTIC TRAUMA GTK210=GTA406=2024-2025 DR.NAZREY 42 NOISE INDUCED HEARING LOSS A sensoryneural hearing loss that is attributed to noise and for which no other etiology can be determined Slowly developing hearing loss over a long period as a result of exposure to continuous or intermittent level noise (ACOEM) GTK210=GTA406=2024-2025 DR.NAZREY 43 CHARACTERISTICS It always sensorineural It almost always bilateral Almost never produces a profound hearing loss Once the exposure to noise is discontinued, there is no significant further progression The earliest damage to the inner ears reflects a loss at 3000, 4000 and 6000 Hz, the greatest loss occurs at 4000 Hz At stable condition, loses as above will reach maximal level in about 10 to 15 years Continuous noise > Interrupted noise Gradual deterioration of hearing Difficulty in comprehending speech Hear vowel sounds better than consonant sounds distortion of speech sounds Associated with tinnitus inability to fall a sleep and concentrate in quite room GTK210=GTA406=2024-2025 DR.NAZREY 44 PATHOPHYSIOLOGY OF NIHL Moderate Exposure Trauma to the sensory epithelium (stereociliated hair cells) of the cochlea Vascular, chemical and metabolic changes in sensory cells Loss of stereocilia stiffness possibly results from contraction of the rootlet structures That anchor the stereocilia to the cuticular plate Temporary Threshold Shift (TTS) GTK210=GTA406=2024-2025 DR.NAZREY 45 Temporary Threshold Shift (TTS) -intracellular changes in hair cellsGive time, -swelling of the auditory nerve hearing -stiffness of stereocillia recover Repeated Exposure (few Permanent Threshold Shift (PTS) minutes Permanent loss of stereocilia to few Fracture of the rootlet structure hours) and destructions of sensory cells Replaced by non-functioning scar tissues -impaired cochlear blood flow -damaged of hair cells Exposure continues NO MORE RECOVERY!!!! GTK210=GTA406=2024-2025 DR.NAZREY 46 ACOUSTIC TRAUMA A single accident which produces an abrupt hearing loss (Occupational Safety and Health Administration @ OSHA) Sudden change in hearing as a result of a single exposure to sudden burst of sound (American College Of Occupational And Environmental Medicine @ ACOEM) Eg. Blow to the head, blast noise, explosion Can cause immediate, severe and permanent hearing loss GTK210=GTA406=2024-2025 DR.NAZREY 47 PATHOPHYSIOLOGY OF ACOUSTIC TRAUMA Inner ear is partially protected from the effect of continuous noise by acoustic reflex Reflex triggered to noise > 90dB Middle ear muscles contract and stiffen the conductive system - more resistance to sound entry It onset delayed for a range of 25 to 150 ms as it is neurally mediated High intensity impulse noise penetrates the cochlea before acoustic reflex has been activated and caused injury GTK210=GTA406=2024-2025 DR.NAZREY 48 This is your ear. This is your ear on noise. GTK210=GTA406=2024-2025 DR.NAZREY 49 GTK210=GTA406=2024-2025 DR.NAZREY 50 LEGISLATION GTK210=GTA406=2024-2025 DR.NAZREY 51 FACTORIES AND MACHINERY ACT ED 1967 O (NOISE EXPOSURE K EV REGULATION, 1989) R GTK210=GTA406=2024-2025 DR.NAZREY 52 GTK210=GTA406=2024-2025 DR.NAZREY 53 OCCUPATIONAL SAFETY AND HEALTH ACT 1994 (NOISE EXPOSURE, REGULATION 2019) GTK210=GTA406=2024-2025 DR.NAZREY 54 GTK210=GTA406=2024-2025 DR.NAZREY 55 READ!!!!! GTK210=GTA406=2024-2025 DR.NAZREY 56 SALIENT PROVISION Noise standard Allowable exposure Noise exposure assessment Audiometric testing & medical examination Employee information & training programme Establish proper record keeping GTK210=GTA406=2024-2025 DR.NAZREY 57 GTK210=GTA406=2024-2025 DR.NAZREY 58 NOISE STANDARD Action Level (AL) =82 dB(A) Equivalent continuous sound level of 82 dB(A) or daily dose = 0.5 Permissible Exposure Level (PEL) Continuous Steady Noise =For 8 Hours : 85 dB(A) =For Ceiling Limit : 115 dB(A) Equivalent continuous sound level of 85 dB(A) Noise level exceeding 115 db(A) at any time Impulsive Noise =140 dB(A) Not exceeding a peak sound pressure level of 140 dB(A) GTK210=GTA406=2024-2025 DR.NAZREY 59 REQUIREMENT Excessive noise producing equipments / operation All factories in which persons are employed in any occupation involving exposure to excessive noise levels in workplace Conservation and controls E=S=I=E=A=P Audiometric test programs Hearing protectors Each employee is responsible for wearing hearing protectors in those areas where mandatory use has been designated GTK210=GTA406=2024-2025 DR.NAZREY 60 Caution signs On equipment and entrances or areas where employees may be exposed to noise levels in excess of 82 dB(A) Clearly worded caution signs posted Training All employees at risk Data monitoring and evaluation To monitor program Employees responsible to provide feedback on program merits and shortcomings to supervisors GTK210=GTA406=2024-2025 DR.NAZREY 61 PENALTY GTK210=GTA406=2024-2025 DR.NAZREY 62 Accepted exposure times for noise before damage occurs Noise Exposure dB(A) Duration per day before damage occurs 85 8 hours 88 4 91 2 94 1 97 30 mins 100 15 103 8 106 4 109 2 115 30 secs GTK210=GTA406=2024-2025 NIOSH DR.NAZREY 63 GTK210=GTA406=2024-2025 DR.NAZREY 64 MAXIMUM EXPOSURE ALLOWED PERDAY Decibels Hours 85 16 90 8 95 4 100 2 105 1 110 30 minutes 115 15 minutes GTK210=GTA406=2024-2025 OSHA DR.NAZREY 65 GTK210=GTA406=2024-2025 DR.NAZREY 66 HEARING CONSERVATION PROGRAMME (HCP) GTK210=GTA406=2024-2025 DR.NAZREY 67 HEARING CONSERVATION PROGRAM (HCP) Noise Induced Hearing Loss GTK210=GTA406=2024-2025 Drop the volume!!!! DR.NAZREY 68 WHY CARE ABOUT NOISE IN WORKPLACE Good employers care about their workers The costs of hearing loss are passed on to you The law requires it GTK210=GTA406=2024-2025 DR.NAZREY 69 COMPONENTS What Constitutes A Hearing Conservation Program? 1. Noise surveys & exposure monitoring 2. Controlling excessive noise 3. Procedures for preventing additional hearing loss 4. Baseline & annual audiometric testing 5. Hearing protection 6. Employee information, instruction and training 7. Record keeping and evaluation GTK210=GTA406=2024-2025 DR.NAZREY 70 1 Noise Surveys And Exposure Monitoring GTK210=GTA406=2024-2025 DR.NAZREY 71 NOISE SURVEYS & EXPOSURE MONITORING Preliminary survey : - Identify hazardous areas and extent of problem Detailed survey : - Identify employees to include in HCP - Enable proper selection of HPD - Develop guidelines for controls Environment level monitoring and personnel monitoring Repetition of monitoring Exposed employees shall be notified Should be done by competent and well trained person known as Noise Risk Assessor (NRA) GTK210=GTA406=2024-2025 DR.NAZREY 72 Noise Personal Environmental Monitoring Noise Sound Dosimeter Level Meter Calculate Calculate Dose Value Frequency DOSH DOE GTK210=GTA406=2024-2025 DR.NAZREY 73 PERSONAL NOISE MONITORING Noise dose: Ambient vs. Inside ESP Industrial Sand Mine 120 100 Ambient Inside ESP Percent dose 80 60 40 20 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 Measurement Number GTK210=GTA406=2024-2025 DR.NAZREY 74 NOISE DOSIMETER GTK210=GTA406=2024-2025 DR.NAZREY 75 GTK210=GTA406=2024-2025 DR.NAZREY 76 ENVIRONMENTAL NOISE MONITORING GTK210=GTA406=2024-2025 DR.NAZREY 77 SOUND LEVEL METER 16k 8k 4k 2k 1k 500 250 125 63 31,5 GTK210=GTA406=2024-2025 DR.NAZREY 78 GTK210=GTA406=2024-2025 DR.NAZREY 79 TERMS LPeak In the Noise and Sound applets, the PEAK LEVEL is the highest instantaneous sound pressure level recorded during a measurement interval. Unlike the maximum level, the peak is detected independently of dosimeter settings for response rate or weighting. Under OSHA regulations, unprotected workers may not be exposed to peak sound levels greater than 140 dB. GTK210=GTA406=2024-2025 DR.NAZREY 80 LMax The MAXIMUM LEVEL is the highest sound level recorded during a measurement interval with a particular response setting (Slow or Fast) and weighting (A or C). LMax is the highest value that is included in LAvg or dose calculations. Under OSHA regulations, unprotected workers may not be exposed to maximum sound levels greater than 115 dB, measured with a slow response rate. GTK210=GTA406=2024-2025 DR.NAZREY 81 LAvg The AVERAGE SOUND LEVEL (in dB) computed for a chosen time duration, based on a 4, 5, or 6 dB exchange rate. LAvg with a 3 dB exchange rate is referred to as LEQ (equivalent sound level). All sound levels at or above the threshold level are averaged into the calculations relating to noise exposure. LAvg is typically calculated with no threshold or with a threshold of 85 dB or 90 dB. GTK210=GTA406=2024-2025 DR.NAZREY 82 LEQ The EQUIVALENT CONTINUOUS SOUND LEVEL is the average sound level for the measurement period based on a 3 dB exchange rate. The term LEQ is functionally the same as LAvg except that LEQ is used only when the exchange rate is set to 3 dB and the threshold is set to None. GTK210=GTA406=2024-2025 DR.NAZREY 83 Exchange Rate The number of decibels that a sound must change in order to either halve or double the rate of dose accumulation. The exchange rate is also called the DOUBLING RATE. Regulatory limits on unprotected exposure are commonly stated in terms of the maximum permissible exposure time (criterion length) at a specific sound level (criterion level). For example, OSHA specifies a maximum exposure time of 8 hours at 90 dBA (A-weighted decibels). Because OSHA's exchange rate is 5 dB, for every 5 decibels the noise exposure increases, the permissible exposure time is cut in half, and for every 5 decibels the noise exposure decreases, the permissible exposure time is doubled. Thus, a worker could be exposed to a noise level of 95 dB for only 4 hours. The exchange rate affects the integrated readings of LAvg, dose, and TWA but does not affect the instantaneous sound level. GTK210=GTA406=2024-2025 DR.NAZREY 84 Weighting The filtering of sound before averaging. A, B, C, and Linear are the standard weighting networks (circuits) available in noise dosimeters and sound-level meters. These frequency filters cover the frequency range of human hearing. A-weighting is the most commonly used filter in both industrial noise applications and community noise regulations. A-weighted measurements are written as dBA or dB(A). The A-weighted filter attempts to make the dosimeter respond the way the human ear hears. This filter attenuates the frequency below several hundred hertz as well as the high frequencies (about 8000 Hz). B-weighting is similar to A but with less attenuation. The B- weighting is very seldom, if ever, used. Quest Technologies instruments typically provide A-weighted GTK210=GTA406=2024-2025 DR.NAZREY and C-weighted 85 measurements. C-weighting provides a fairly flat frequency response with only slight attenuation of the very high and low frequencies. C- weighting is intended to represent how the ear perceives sound at high decibel levels. C-weighting is often used as a flat response when Linear weighting is not available. C-weighted measurements are written as dBC or dB(C). Linear Weighting has a flat frequency response curve over the entire measurement frequency range. Linear weighting is most commonly found on upper-model sound-level meters and is typically used for performing audiometric analysis and octave band filter analysis. Linear weighting is being replaced by Z- weighting, which is defined as flat from 20 Hz to 20 KHz. GTK210=GTA406=2024-2025 DR.NAZREY 86 INSTRUMENT CALIBRATION In The Field Before and After each usage (monitoring) Detailed log By An Independent Party (Lab) Once a year Calibration Certificate GTK210=GTA406=2024-2025 DR.NAZREY 87 ACOUSTICAL CALIBRATORS Typical Calibrator Loudspeaker; single or dual output ON/OFF Switch Battery Indicator GTK210=GTA406=2024-2025 DR.NAZREY 88 Microphone Adapter SoundPro SE/DL Small-Compact meets latest IEC 61672 Standards. GTK210=GTA406=2024-2025 DR.NAZREY 89 SE Color Display GTK210=GTA406=2024-2025 DR.NAZREY 90 1/1 and 1/3 Octave Band Measurements GTK210=GTA406=2024-2025 DR.NAZREY 91 SD Memory Card GTK210=GTA406=2024-2025 DR.NAZREY 92 GTK210=GTA406=2024-2025 DR.NAZREY 93 GTK210=GTA406=2024-2025 DR.NAZREY 94 2 GTK210=GTA406=2024-2025 Controlling Excessive Noise DR.NAZREY 95 NOISE CONTROL OPTIONS Control the SOURCE Control the NOISE PATH Protect the RECEIVER Source Path Receiver GTK210=GTA406=2024-2025 DR.NAZREY 96 NOISE CONTROL MAP Engineering Admin PPE Source Modify “Buy Quiet” process or Substitute equipment Eliminate Maintenance Path Absorbers Isolate noise: Enclosures oby time Isolate oby location Receiver Restrict exposure Ear Plugs Training & Ear Muffs education GTK210=GTA406=2024-2025 DR.NAZREY 97 WHAT TO DO TO CONTROL NOISE? For new workplaces or existing workplaces that are having new plant installed : Design the workplaces to be low noise environments Consider noise output when purchasing new plant and machinery - BUY QUIET… GTK210=GTA406=2024-2025 DR.NAZREY 98 For existing workplaces Write a noise control plan and set priorities Identify where noise cannot be controlled Consider how to reduce noise Consider how to reduce noise transmission : Place noisy processes in a separate workplace Eliminate excessive vibration Use soundproofing to prevent sound reflecting Do noisy processes at times less workers are around Enclose noisy machinery Enclose operators to work in GTK210=GTA406=2024-2025 DR.NAZREY 99 Protect people by : Restricting their time in a noisy environment Training and supervision on how to work quietly Warn employees through signs As a final result, have a HEARING CONSERVATION PROGRAMME AND PERSONAL PROTECTIVE EQUIPMENT PROGRAMME GTK210=GTA406=2024-2025 DR.NAZREY 100 BREAK...PLEASE! PLEASE! PLEASE! GTK210=GTA406=2024-2025 DR.NAZREY 101 GTK210=GTA406=2024-2025 DR.NAZREY 102 GTK210=GTA406=2024-2025 DR.NAZREY 103 3 Procedures Preventing Additional Hearing GTK210=GTA406=2024-2025 Loss DR.NAZREY 104 PURPOSE Preventive program To establish requirements and procedures that eliminate, prevent or minimize risk of hearing loss or impairment from exposure to excessive noise levels at work GTK210=GTA406=2024-2025 DR.NAZREY 105 SCOPE Applies to all activities or factories where persons are employed in any occupation involving exposure to excessive noise levels at workplace GTK210=GTA406=2024-2025 DR.NAZREY 106 RESPONSIBILITIES EMPLOYER / SUPERVISOR Ensure that employees are provided with hearing protectors when required Noise hazardous equipments are labeled Notify DOSH of noise complaints or potential noise hazards or process, material and equipment changes that may alter noise exposures Ensure audiometric test for the necessary employees Ensure new employee training and annual refresher training for potentially affected employees GTK210=GTA406=2024-2025 DR.NAZREY 107 EMPLOYEE Wear hearing protective device as required Attend required training sessions on noise hazards GTK210=GTA406=2024-2025 DR.NAZREY 108 AUDIOLOGIST / OCCUPATIONAL HEALTH DOCTOR Provide valid baseline audiogram, audiometric testing and audiometric evaluation 3 MONTHS from the day the employee commences work Maintain audiometric test records Audiometric measuring equipment : approved type and shall be calibrated and maintained at regular intervals Provide comprehensive training program annually Recommend appropriate hearing protectors Record of medical and occupational health history, eg : ear disease and exposure to noise GTK210=GTA406=2024-2025 DR.NAZREY 109 NOISE RISK ASSESSOR (NRA) Workplace and employee noise evaluation Noise assessment to determine whether control measures needed and how GTK210=GTA406=2024-2025 DR.NAZREY 110 DOE AND DOSH Administering HCP Workplace and employee noise evaluation Noise assessment to determine whether control measures needed and how Determine which job titles need periodic evaluation of employees’ exposure Maintain records of employee exposure measurement GTK210=GTA406=2024-2025 DR.NAZREY 111 HOW TO PREVENT NIHL 1. Engineering Control : REMOVE THE HAZARD Maintenance and adjustment of machinery Eliminate or substitute noisy equipments with quieter ones Vibration mounting Barriers, partition or isolation of noise source 2. Administrative Control : REMOVE THE WORKER Limit employees’ time in noise hazard area Limit duration of noisy operation Increase distance between employee and noise source 3. Personal Hearing Protectors : PROTECT THE WORKER Ear muffs Ear plug Canal plug GTK210=GTA406=2024-2025 DR.NAZREY 112 HOW TO PREVENT NIHL Hierarchy of prevention ESIEAP Level of prevention Primordial / Primary / Secondary / Tertiary Noise reduction Substitution Engineering control Exposure reduction Administrative procedures and arrangements Use of hearing protection devices GTK210=GTA406=2024-2025 DR.NAZREY 113 HOW TO PREVENT NIHL Principles of engineering control ABSORPTION Sound energy is absorbed whenever sound meets a porous material. Porous materials intended to absorb sound is called absorbents. Absorbents usually absorb 50-90 % incident sound energy. GTK210=GTA406=2024-2025 DR.NAZREY 114 GTK210=GTA406=2024-2025 DR.NAZREY 115 GTK210=GTA406=2024-2025 DR.NAZREY 116 HOW TO PREVENT NIHL INSULATION When sound meets a wall or partition, only a small proportion of sound energy passes through, most are reflected back. A wall of 10 dB insulation allows 10 % of the sound energy to pass through, 20 dB corresponds to 1 %, 30 dB corresponds to 0.1 %, etc. GTK210=GTA406=2024-2025 DR.NAZREY 117 GTK210=GTA406=2024-2025 DR.NAZREY 118 GTK210=GTA406=2024-2025 DR.NAZREY 119 CONTROL Source : ILO Noise at Work OF NOISE Noise- Insulated Air Compressor GTK210=GTA406=2024-2025 DR.NAZREY 120 HOW TO PREVENT NIHL SILENCER The length and diameters of the chamber and opening determines the frequency and level of attenuation respectively. Use of absorption and insulation principles. GTK210=GTA406=2024-2025 DR.NAZREY 121 GTK210=GTA406=2024-2025 DR.NAZREY 122 CONTROL Source : ILO Noise at Work OF NOISE Put a silencer on the machine GTK210=GTA406=2024-2025 DR.NAZREY 123 HOW TO PREVENT NIHL VIBRATION ISOLATION Isolation of vibrating machines from floors or room from vibrating floors. By mounting vibration sources on flexible supports. Eg : Spring used for heavy machinery; rubber, cork, expanded polystyrene used for light structures. GTK210=GTA406=2024-2025 DR.NAZREY 124 HOW TO PREVENT NIHL DAMPING If a panel is set into vibration, the level of vibration, hence noise level will diminish with time. Reducing the amplitude of vibration reduces resonance peaks hence reducing the noise radiated. Stiffening the vibrating surfaces with metal, spray on damping material, hardboard. GTK210=GTA406=2024-2025 DR.NAZREY 125 GTK210=GTA406=2024-2025 DR.NAZREY 126 CONTROL Source : ILO Noise at Work OF NOISE GTK210=GTA406=2024-2025 DR.NAZREY 127 1.5mm stiffened plate reduceds vibrations HOW TO PREVENT NIHL Principles of administration control DISTANCE Sound that propagates from a point source in free air attenuates by 6 dB for each doubling of distance from source. For indoors, attenuation is less due to contributions to the total sound level from reverberant sound brought about by reflection from walls and ceilings. GTK210=GTA406=2024-2025 DR.NAZREY 128 CONTROL Source : ILO Noise at Work OF NOISE meter Simple Method of Knowing How Much Sound is Reduced by Distance GTK210=GTA406=2024-2025 DR.NAZREY 129 GTK210=GTA406=2024-2025 DR.NAZREY 130 HOW TO PREVENT NIHL ENCLOSURE Thinking about which ENCLOSURES GTK210=GTA406=2024-2025 DR.NAZREY 131 HOW TO PREVENT NIHL NOISE MAPPING COLOUR ZONE GTK210=GTA406=2024-2025 DR.NAZREY 132 4 Baseline And Annual Audiometric GTK210=GTA406=2024-2025 Testing DR.NAZREY 133 TOPICS History Clinical Examination Diagnosis of Hearing Loss Non Occupational Occupational Audiometric Tests Subjective Objective GTK210=GTA406=2024-2025 DR.NAZREY 134 PRE-AUDIOMETRIC PROCEDURES 1. Particulars of employee 2. Hobbies, employment history, sociality 3. Medical history 4. Present medical condition 5. Clinical / Ear Examination GTK210=GTA406=2024-2025 DR.NAZREY 135 PARTICULARS OF EMPLOYEE Name, gender, age, I/C Test date Proxy of exposure - work area - designation - employment date - noise level (max LEQ) - noise dose GTK210=GTA406=2024-2025 DR.NAZREY 136 HOBBIES, EMPLOYMENT AND SOCIALITY Other exposure related to noise and pressure - loud noise - barometric pressure (Boyle’s Law) - occupations : 1. Divers 2. Pilot 3. Armed forces, police 4. Mining activities etc PPE Smoking GTK210=GTA406=2024-2025 DR.NAZREY 137 MEDICAL HISTORY Occupational noise exposures Non occupational noise exposures HEARING LOSS GTK210=GTA406=2024-2025 DR.NAZREY 138 MEDICAL HISTORY History of other risk factors Head trauma / injury Ear infection : CSOM Ear : discharge, bleeding, ear ache, tinnitus Other related diseases : Mumps, Measles Nose and throat problems Ototoxic drug : Gentamicin, Frusemide, Aspirin Genetic and family history of hearing loss Hearing loss GTK210=GTA406=2024-2025 DR.NAZREY 139 PRESENT MEDICAL CONDITION Exposure to noise < 14 hours Common cold Ear discharge Exposure to barometric pressure – divers, pilot GTK210=GTA406=2024-2025 DR.NAZREY 140 RESULTS OF FOCUS GROUPS Workers may be less concerned about getting a hearing loss then about developing tinnitus. “I expected to lose my hearing. But, I thought it would be quiet.” GTK210=GTA406=2024-2025 DR.NAZREY 141 CLINICAL / EAR EXAMINATION General Examination Ear Examination (Otoscopy) External Auditory Meatus / Canal : wax, foreign body Tympanic membrane patency GTK210=GTA406=2024-2025 DR.NAZREY 142 GTK210=GTA406=2024-2025 DR.NAZREY 143 GTK210=GTA406=2024-2025 DR.NAZREY 144 Hyperemic Tympanic Membrane GTK210=GTA406=2024-2025 DR.NAZREY 145 Perforated Tympanic Membrane GTK210=GTA406=2024-2025 DR.NAZREY 146 DIFFERENTIAL DIAGNOSIS Non Occupational HL Presbycusis - associated with aging Hereditary Hearing Impairment - early age onset Metabolic disorders : DM, thyroid, renal failure Sudden sensorineural hearing loss Infectious origin : meningitis, encephalitis CNS diseases : acoustic neuroma, multiple sclerosis Meniere’s disease Occupational HL Noise Induced Hearing Loss (NIHL)* Hearing Loss due to physical trauma GTK210=GTA406=2024-2025 DR.NAZREY 147 HEARING EVALUATION Subjective Audiometric Tests : Test of Spoken Words Tuning Fork Tests Objective Audiometric Tests : PURE TONE AUDIOMETRY Speech Audiometry Impedance (Immittance) Audiometry Bekesy Audiometry Evoked Response (Brain Stem) Audiometry Otoacoustic Emissions Stenger Test - detect feigned unilateral HL GTK210=GTA406=2024-2025 DR.NAZREY 148 Test of Spoken Word Simplest form Patient is asked to repeat spoken words of increasing intensity while competing noises (crumpling of paper or the sounds from a Baranay noise box) in opposite ear Results – ability to hear a soft whisper, loud whisper, soft spoken voice, loud spoken voice or shout GTK210=GTA406=2024-2025 DR.NAZREY 149 Tuning Fork Test 512 Hz tuning fork 1. Rinne Test Air Conduction (tuning fork placed by the opening of the ear canal) Bone Conduction (tuning fork placed on the mastoid bone) AC > BC = Patient hears air conduction better than bone conduction Normal or Sensorineural Hearing Loss AC < BC = When bone conduction is louder than air conduction conductive defness GTK210=GTA406=2024-2025 DR.NAZREY 150 Tuning Fork Test 512 Hz tuning fork 2. Weber Test Tuning fork placed in the forehead Sound should lateralized towards a conductive loss and away from sensorineural one Serial Test from 512 to 4096 Hz are used a marked in hearing in higher frequencies GTK210=GTA406=2024-2025 DR.NAZREY 151 GTK210=GTA406=2024-2025 DR.NAZREY 152 Speech Audiometry To assess speech reception and comprehension 1. Speech Reception Threshold (SRT) Is the intensity in which the listener is able to repeat 50 % of balanced two syllable words 2. Speech Discrimination Score (SDS) Non syllabic words are presented at intensities well above the threshold for SR (SRT + 25-40 dB) GTK210=GTA406=2024-2025 DR.NAZREY 153 GTK210=GTA406=2024-2025 DR.NAZREY 154 Impedence Audiometry 1. Tympanometry Employs acoustic probe to measure the impedance of the eardrum and ossicular chain Results Compliance auditory tube dysfunction Noncompliance TM perforation / ME effusion Compliance laxity of TM / disruption of ossicular chain GTK210=GTA406=2024-2025 DR.NAZREY 155 Impedence Audiometry 2. Acoustic Reflex Testing Response of loud noise contraction of ME muscles, results in a measurable rise in ME impedance Yield information regarding the integrity of auditory portion of CNS GTK210=GTA406=2024-2025 DR.NAZREY 156 GTK210=GTA406=2024-2025 DR.NAZREY 157 Békésy Audiometry A person uses self directed techniques that involve pressing and releasing a signal button, press a button when they hear a tone and vice versa Commonly used in industrial testing but generally not reliable for screening purpose GTK210=GTA406=2024-2025 DR.NAZREY 158 Evoked Response Audiometry To rule out retrocochlear lesions : 8th cranial nerve, brain stem of cortex Evoked potential which are elicited in response to clicking noises and recorded via scalp electrodes pinpoint lesion’s location A significant delay / complete absence of a response CP angle tumor / at brain stem Definitive diagnosis : CT Scan / MRI GTK210=GTA406=2024-2025 DR.NAZREY 159 GTK210=GTA406=2024-2025 DR.NAZREY 160 GTK210=GTA406=2024-2025 DR.NAZREY 161 PURE TONE AUDIOMETRIC TESTING (PTA) GTK210=GTA406=2024-2025 DR.NAZREY 162 OBJECTIVES Meet legal requirement Get valid and reliable test whether normal or abnormal individuals Identify susceptible individuals Identify inadequately protected individuals and take corrective action Eg. PPE Gauge performance of Hearing Conservation Program Enhances motivational efforts to prevent further hearing loss GTK210=GTA406=2024-2025 DR.NAZREY 163 PURE TONE AUDIOMETR Y (PTA) By audiologist / contracted physician For all employees exposed at or above Action Level Baseline audiogram within 3 months from day of job commencement Preceded by period of quiet for 14 hours before test Done in quiet room meeting the standard requirement with background noise level specified in Second Schedule GTK210=GTA406=2024-2025 DR.NAZREY 164 PURE TONE AUDIOMETR Y (PTA) No cost to employee Supervision by registered medical practitioner Separately for each ear Employees be informed within 21 days when audiogram shows threshold shift that is work related GTK210=GTA406=2024-2025 DR.NAZREY 165 PURE TONE AUDIOMETR Y (PTA) Air conduction test for frequencies 500, 1000, 3000, 4000 & 6000 Hz taken for each ear Sensitivity to Pure Tones - measured at 250, 500, 1000, 2000, 3000, 4000, 6000 & 8000 Hz for both air conduction (head phones) and bone conduction (bone oscillator) Threshold of hearing : Normal = 0 – 20 dB Masking of contra lateral ear with competing sound is necessary when asymmetry exist which difference of intensity between 2 ears is more than 40 dB, indication of masking is required for Non Test Ear GTK210=GTA406=2024-2025 DR.NAZREY 166 Masking GTK210=GTA406=2024-2025 DR.NAZREY 167 PURE TONE AUDIOMETR Y (PTA) 1. Baseline audiograms Use to compare subsequent audiogram Medical and Occupational history 2. Frequency of audiometric test Every year (i) > PEL (ii) Hearing Impairment (iii) STS Once in 2 years (i) Exposure > AL but < PEL GTK210=GTA406=2024-2025 DR.NAZREY 168 HOW TO DO AUDIOMETRIC TESTING 1.Audiometer 2.Audiometer booth 3.Workers 4.Tester 5.Precaution 6.Feedback 7.Follow-up GTK210=GTA406=2024-2025 DR.NAZREY 169 AUDIOMETER 1.Audiometer approved by DOSH 2.Calibrated every 6 MONTHS for Static Booth & DAILY for Mobile Booth 3.Audio-cup & other wire connection functioning normally 4.All the audiometer functioning normally GTK210=GTA406=2024-2025 DR.NAZREY 170 GTK210=GTA406=2024-2025 DR.NAZREY 171 Printer Audiometer GTK210=GTA406=2024-2025 DR.NAZREY 172 Test of Air Conduction GTK210=GTA406=2024-2025 DR.NAZREY 173 Audiometer GTK210=GTA406=2024-2025 DR.NAZREY 174 AUDIOGRAM 4 types : 1) Graphic Display Audiogram determines type, degree and configuration of Hearing Loss 2) Tabular Audiogram 3) Bekesy (Self Recording) Audiogram 4) Computerized Audiogram GTK210=GTA406=2024-2025 DR.NAZREY 175 Graphic Display Audiogram GTK210=GTA406=2024-2025 DR.NAZREY 176 Symbols and Concept of Threshold GTK210=GTA406=2024-2025 DR.NAZREY 177 GTK210=GTA406=2024-2025 DR.NAZREY 178 Tabular Audiogram Very straight forward Simply right down the thresholds in a table Commonly used by Hearing Conservationists GTK210=GTA406=2024-2025 DR.NAZREY 179 Self Recording (Bekesy) Audiogram GTK210=GTA406=2024-2025 DR.NAZREY 180 Computerized Audiogram Use of a computer It presents the sounds automatically and adjusts the intensity and frequency depending on how a person responds Only for air conduction GTK210=GTA406=2024-2025 DR.NAZREY 181 AUDIOMETER BOOTH / SILENT BOOTH 1.Sound inside the booth is according to standard 2.Ventilation, cleanliness and lighting inside the booth are good 3.Door can be opened from inside GTK210=GTA406=2024-2025 DR.NAZREY 182 Audiometric @ Silent Booth Audiometer Printer GTK210=GTA406=2024-2025 DR.NAZREY 183 Audiometric @ Silent Booth GTK210=GTA406=2024-2025 DR.NAZREY 184 GTK210=GTA406=2024-2025 DR.NAZREY 185 Earphones : In industrial testing : Supra-Aural Earphones Coded as Red and Blue GTK210=GTA406=2024-2025 DR.NAZREY 186 WORKER S 1.Ensure co-operation from the worker 2.History 3.Ear examination 4.Explain to the worker about the test & the regulatory requirement 5.Explain testing procedure to the workers GTK210=GTA406=2024-2025 DR.NAZREY 187 EXPLAINATION TO THE WORKER S 1.How to use signal respond by pressing & releasing immediately 2.Familiarize the worker with the tone by letting the worker listen to the tone & signal 3.Headset placement Remove eye glasses & earrings Audio-cup : Red Right / Blue Left Place earphones directly at the opening of the ear canal Adjust to ensure tight fit Seat employee sideways from the tester so there is no visible clue GTK210=GTA406=2024-2025 DR.NAZREY 188 GTK210=GTA406=2024-2025 DR.NAZREY 189 TESTER Educate the worker Press signal 1-2 second only Test Better Ear First If both ears the hearing is normal then start with the right ear Test one ear each time for 500 Hz, 1000 Hz, 2000 Hz, 3000 Hz, 4000 Hz, 6000 Hz & 8000 Hz Start with 1000 Hz with signal 40 dB (a) If worker responds, reduce the intensity by 10 dB (b) If no response, increase the intensity by 5 dB Get 2 positive intensity response from a frequency to confirm lowest audible tone GTK210=GTA406=2024-2025 DR.NAZREY 190 GTK210=GTA406=2024-2025 DR.NAZREY 191 GTK210=GTA406=2024-2025 DR.NAZREY 192 PRECAUTION ,FEEDBACK, FOLLOW-UP Do not give signal at fixed interval Do not give gestures E.g. looking at the worker when you give the signal Give brief remarks about the audiogram results 1.Praise him if the result is good 2.Warn him for better PPE utilization 3.Motivate workers to protect their hearing 4.Counseling GTK210=GTA406=2024-2025 DR.NAZREY 193 PURE TONE AUDIOMETRIC TESTING RESULT GTK210=GTA406=2024-2025 DR.NAZREY 194 Audiogram Interpretation NORMAL HEARING LOSS (HL) Hearing threshold at or more than 25 dB in any frequency HEARING IMPAIRMENT (HI) Average permanent hearing threshold at 500 Hz, 1000 Hz, 2000 Hz and 3000 Hz shifted 25 dB or more from reference GTK210=GTA406=2024-2025 DR.NAZREY 195 STANDARD THRESHOLD SHIFT (STS) An average shift of more than 10 dB at frequencies of 2000, 3000, 4000 Hz relative to the baseline audiogram in either ear Pathophysiology Temporary Threshold Shift : Hair cell fatigue Permanent Threshold Shift : Hair cell atrophy Temporary Threshold Shift : Re-test within 3 months GTK210=GTA406=2024-2025 DR.NAZREY 196 NIHL : Key Points Audiometric Result Usually reveals a bilateral deafness Frequently in the higher frequency SNHL with a maximum drop a 4000 Hz on PTA Lower and High frequencies are affected later if exposures continues NIHL cannot always be established by the shape of audiogram due to great variability GTK210=GTA406=2024-2025 DR.NAZREY 197 AUDIOGRAM Frequency (Hz) 500 1 2 3 4 6 -5 dB 0 10 20 30 40 50 GTK210=GTA406=2024-2025 DR.NAZREY 198 NORMAL Frequency (Hz) 500 1 2 3 4 6 -5 dB 0 10 20 30 40 50 GTK210=GTA406=2024-2025 DR.NAZREY 199 HL 4000 & 6000 Hz Frequency (Hz) 500 1 2 3 4 6 -5 dB 0 10 20 30 40 50 GTK210=GTA406=2024-2025 DR.NAZREY 200 HL 500, 2000, 4000, 6000 Hz & HI Frequency (Hz) 500 1 2 3 4 6 -5 dB 0 10 20 30 40 50 GTK210=GTA406=2024-2025 DR.NAZREY 201 HL 3000, 4000, 6000 & STS Frequency (Hz) 500 1 2 3 4 6 -5 dB 0 BASELINE 10 20 30 40 50 RECENT GTK210=GTA406=2024-2025 DR.NAZREY 202 HI & HL 1000 - 6000 & STS Frequency (Hz) 500 1 2 3 4 6 -5 dB 0 BASELINE 10 20 30 40 50 RECENT GTK210=GTA406=2024-2025 DR.NAZREY 203 GTK210=GTA406=2024-2025 DR.NAZREY 204 GTK210=GTA406=2024-2025 DR.NAZREY 205 Types of Hearing Loss GTK210=GTA406=2024-2025 DR.NAZREY 206 Degree of Hearing Loss GTK210=GTA406=2024-2025 DR.NAZREY 207 GTK210=GTA406=2024-2025 DR.NAZREY 208 GTK210=GTA406=2024-2025 DR.NAZREY 209 Configuration of Hearing Loss GTK210=GTA406=2024-2025 DR.NAZREY 210 BREAK... PLEASE! PLEASE! PLEASE! GTK210=GTA406=2024-2025 DR.NAZREY 211 GTK210=GTA406=2024-2025 DR.NAZREY 212 5 GTK210=GTA406=2024-2025 Hearing Protection DR.NAZREY 213 HEARING PROTECTION Employees exposed to noise above 8-hour TWA of 85 dBA shall wear hearing protectors HPD shall be made available to employees exposed to noise at or above action level at no cost to them HPD must attenuate noise level to an 8-hour TWA of 85 dBA or less Supervision and reevaluation of HPD must be done Workplace with noise levels exceeds 82 dBA shall have signs posted – “HEARING PROTECTORS REQUIRED” GTK210=GTA406=2024-2025 DR.NAZREY 214 When Should You Wear A Hearing Protection Device? Whenever exposed to noise that is 85 decibels or greater for an 8-hour period of time GTK210=GTA406=2024-2025 DR.NAZREY 215 GTK210=GTA406=2024-2025 DR.NAZREY 216 HOW TO CHOOSE There are many styles, models and brands of plugs and muffs. Noise Reduction Rating (NRR) number on the package is the first criteria. The higher the number, the more protective is the device if it fits properly. Earmuffs available in the market range from 15 dB to 29 dB NRR. Devices must fit the ear snugly but not cause discomfort so try them in a noisy room and make sure there is a significant reduction on noise volume. GTK210=GTA406=2024-2025 DR.NAZREY 217 HOW TO CHOOSE What are some of the barriers cited by construction workers and their supervisors? There are over 200 different hearing protectors. Everyone can find a protector that meets their needs. THE BEST HEARING PROTECTOR IS THE ONE THAT’S WORN! The Four C’s Comfort Convenience Cost (Personal and $$$$$$$$) Communications / hear important sounds GTK210=GTA406=2024-2025 DR.NAZREY 218 HEARING LOSS PREVENTION Area Definition High Noise Area OR > 85 dB(A) Extremely High Noise Area AND > 97 dB(A) Ear Muffs Can Be OR GTK210=GTA406=2024-2025 DR.NAZREY 219 0 Sound Reduction 0 Earmuff 20 Earplug 30 40 50 100 200 500 1000 2000 5000 10000 Frequency (Hz) GTK210=GTA406=2024-2025 DR.NAZREY 220 GTK210=GTA406=2024-2025 DR.NAZREY 221 GTK210=GTA406=2024-2025 DR.NAZREY 222 GTK210=GTA406=2024-2025 DR.NAZREY 223 GTK210=GTA406=2024-2025 DR.NAZREY 224 https://www.noisemeters.com/apps/occ/prot-nrr.asp GTK210=GTA406=2024-2025 DR.NAZREY 225 “The best hearing protector is the one that the worker will wear” NIOSH, 1998 GTK210=GTA406=2024-2025 DR.NAZREY 226 6 Employee Information Instruction And Training GTK210=GTA406=2024-2025 DR.NAZREY 227 EMPLOYEE EDUCATION AND TRAINING Annual training for all employees exposed to noise at or above TWA 85 dBA Training must cover the following information : Effects of noise on hearing Recognizing hazardous noise Purpose, advantage, disadvantage and attenuation of various types of HPD Instruction for proper fitting and care Purpose and procedure of audiometric testing Provisions of regulations and mandatory to follow regulation Repeated at least 2 yearly GTK210=GTA406=2024-2025 DR.NAZREY 228 GTK210=GTA406=2024-2025 DR.NAZREY 229 GTK210=GTA406=2024-2025 DR.NAZREY 230 Don’t make the mistake of thinking your job is over if you simply provide hearing protection and periodic hearing tests. Without TRAINING workers how to recognize noise hazards, utilize noise controls and use hearing protectors, you may be wasting your money. GTK210=GTA406=2024-2025 DR.NAZREY 231 GTK210=GTA406=2024-2025 DR.NAZREY 232 7 GTK210=GTA406=2024-2025 Record Keeping And Evaluation DR.NAZREY 233 ESTABLISH PROPER RECORD KEEPING Records must be kept by the employer Exposure Monitoring Record : -Include details like employee name, daily noise dose, location, time, type, model date of calibration of measuring equipment -Records maintained as long as employee is employed Audiometric Test Records : -Detailed records -Records retained as long as employee is employed and 5 years thereafter Training records Issuance of hearing protectors records GTK210=GTA406=2024-2025 DR.NAZREY 234 CHALLENGES IN HEARING LOSS GTK210=GTA406=2024-2025 DR.NAZREY 235 MANAGEMENT It’s Really Pretty Simple….. Get their attention GTK210=GTA406=2024-2025 DR.NAZREY 236 EPIDEMIOLOGY In 1981, OSHA estimated that 7.9 million U.S. workers in the manufacturing sector were occupationally exposed to daily noise levels at least or above 80 dB(A) In the same year, U.S. EPA estimated that more than 9 million U.S. workers were occupationally exposed to daily noise levels above 85 dB(A) 8.7 to 11.1 million Americans suffer permanent hearing disability 1 million workers per year experience occupational hearing loss $800 million annual worker’s comp claims 30 million workers are exposed and additional 9 million are at risk for hearing loss from other agents such as solvents and metals 44% of carpenters and 48% of plumbers reported that they had a perceived hearing loss GTK210=GTA406=2024-2025 DR.NAZREY 237 NIOSH estimated 90% of coal miners will have a hearing impairment by age 52 Based on NIOSH survey in 1980s on exposed workers in all economic sectors, it is thought that approximately 30 million American workers are exposed to hazardous noise level alone or combination with ototraumatic agents that are potentially hazardous At present exposure limit, 1:4 will develop a permanent hearing loss as a result of their occupationally exposure to these hazards GTK210=GTA406=2024-2025 DR.NAZREY 238 MALAYSIA No surveillance done yet No statistic for occupational hearing loss SOCSO receive report but still inconclusive in diagnosis MOH is only starting surveillance - no data to date No baseline data available for workers - compensation process difficult Ignorance GTK210=GTA406=2024-2025 DR.NAZREY 239 GTK210=GTA406=2024-2025 DR.NAZREY 240 THANK YOU... A LOT AAAAAAA… GTK210=GTA406=2024-2025 DR.NAZREY 241
