Hearing conservation final exam with correct answers 2024

Forensics - answers-1fo·ren·sic Pronunciation: f&-'ren(t)-sik, -'ren-zik Function: adjective Etymology: Latin forensis public, forensic, from forum forum Date: 1659 1 : belonging to, used in, or suitable to courts of judicature or to public discussion and debate 2 : ARGUMENTATIVE, RHETORICAL Forensic Audiology May Include: - answers-Tort (personal injury) Malpractice Collision Warning signal audibility Worker compensation Product liability Community Noise Criminal law ADA Compliance Due Process Peer Review Criminal Prosecution - answers-If you break the law, you offend the state and face criminal prosecution. Your opponent is the government. Must be found guilty "beyond a reasonable doubt". Civil Law (Torts) - answers-A civil offense violates a duty you owe to your neighbor. Such offenses are called Torts. Standard of proof is more symmetric in civil trials than in criminal trials. Plaintiff needs to prove claim is "probably true", or "more probably than not" to win the case. Health care providers are most commonly involved in "Torts of Negligence". Torts of Negligence - answers-Basis for nearly all malpractice and personal injury suits. Plaintiff claims the defendant failed to exercise due care and caused an injury that requires compensation. The injured party must establish that... 1. The defendant had a duty to the plaintiff. 2. The defendant neglected that duty. 3. An injury or loss occurred. 4. The injury was caused by the defendant's negligence. Witness Types - answers-Custodian of records Fact witness Treating witness Corroborating witness Character witness Rebuttal witness Adverse witness Opinion witness Expert Witness Defined - answers-By education or special training, possesses special knowledge of some particular subject area in greater depth than the public at large. One who assists the triers of fact in understanding complicated subjects not generally understood . The only witness than can offer an opinion. Road to the Courtroom - answers-Complaint Answer (defense response to complaint) Interrogatories (written questions asked by opposing side) Discovery Deposition (always opt to read it) Pretrial conference Players in the Courtroom - answers-Judge & Jury - Triers of Fact Plaintiff Attorney- Prosecutes offense Defense Attorney Court Officers - bailiff, court reporter Witnesses Lay or Ordinary - source of fact What they did or saw - no opinion Expert - source of truth Only witness that can offer opinion In the Courtroom Direct Examination - answers-Establish qualifications. Questions concerning relevant science and medicine. Opinions on one or more of the key elements of the tort (duty, negligence, damage and liability). Possibility of hypothetical questions. In the Courtroom Cross Examination - answers-Opposing attorney's job to impeach the expert's testimony. May include attacks on qualifications, knowledge, experience, reasoning, judgment, impartiality and consistency. Attempt to show expert relied on incorrect or incomplete versions of the facts of the case. Attempt to show expert is relying on a controversial point of view. Re-direct Examination - answers-Clear up confusion from cross-examination. Limited to scope of cross examination. Re-cross Examination - answers-Limited to scope of re-direct examination. *** This cycle can be repeated ad nauseam, but the opposing attorney always gets the last word. Witness Excused Testimony Be Prepared to: - answers-Lecture on the decibel. Discuss Reasonable Medical Certainty, Probability, Possibility. Discuss % Hearing Loss, Impairment,Handicap, Disability. Answer: What is an audiologist? Are you a doctor? Are you licensed? What are you being paid for your testimony? Testimony - answers-Stay within area of expertise. Keep responses brief and clear. Use illustrative material when appropriate. Avoid advocacy - preserve objectivity. Present appropriate appearance/attire. Maintain proper demeanor. Reasonable Medical Probability - answers-Basis of conclusion Supported by research Supported by personal experience Visual Aids - answers-Expect to "donate" materials as evidence exhibits Use of visual aids important for jury White boards / black boards Opinion vs. Honesty - answers-Keep emotions in check Support honest opinions with published research Support honest opinion with personal experience Maintain the perspective of "under current law" Level of Credibility - answers-Did you actually see the patient and perform an evaluation?" Courtroom Dress Code - answers-Conservative Modest Little jewelry Clothes that draw no attention Courtroom Etiquette and Decorum - answers-Defer to the Judge Listen to the Attorney Speak to the Jury "Yes, Your Honor" Do not joke around or be sarcastic Speak in non-professional terms Cut to the chase to keep the jury awake Be brief, and be gone Listen to the question Consider the answer Answer the question and only the question Tell the absolute truth There are two types of questions that may be asked during cross-examination: - answers-The ambiguous question The two-part question. It's interesting to know that the two-part question is where one part of question is true and the other false, in an attempt to "trick" the person being questioned. It is suggested to answer only one part of the question and let the other part of the question be redirected to you. Purpose of the Case - answers-Choose your cases wisely Ensure sufficient expertise in the area of the suit Decline participation if you are not comfortable with aspects Decline participation if you have personal knowledge of aspects that could be prejudicial to your perspective Know who your opponent will be The Expert Witness/Consultant is: - answers-Employee Source of truth Educator Investigator Evaluator Strategist Interpreter Requirements to perform in court - answers-Knowledge Integrity Credibility Affordability Essential Functions - answers-Establish Facts Interpret Facts Comment of Opposing Expert's Facts & Opinions Define Professional Standards You Should: - answers-Ask about the legal process : "What is my role, what will I do?" Receive and review reports and/or tests conducted. Review evidence & testimony. Educate attorney. Know your potential opponents. Anticipate cross examination. Prepare exhibits & simulations. Discuss evidence only with permission. Put comments in writing only when requested to do so. You May: - answers-Review and evaluate documents and reports Give scientific information to strengthen arguments (or contradictory evidence) May measure parameters inherent to the case Give hearing tests on principals of case Help client prepare to to depose opposing experts Determine client's cost of care Setting up an Expert Witness Arrangement: - answers-Case review Retainer agreement Fact finding Final report The lawyer will establish what they want - the extent of information necessary to develop legal strategy After determining level of involvement required, you know what you should do, and can give an estimate of cost ONLY submit in writing information that the lawyer specifically requests in writing Doctor-Patient Relationship - answers-Persons referred by employers, attorneys, etc. for examination regarding employment, litigation, or compensation usually do not establish a doctor-patient relationship with the examining practitioner. By consenting to the examination they are assumed to consent to a report to the referring party (Dobie). How to be ready for the court room - answers-Keep reports concise & understandable. Use precise equipment and standard methodology. Replicate accurately. Pay attention to details. Documentation - answers-Audiogram - standard format Audiometer make and model Reliability Type of earphones used Calibration How patient was instructed Who did the test Speech - live or recorded How much - what type of masking Hearing impairment configuration? Reliability of responses? Are the proper tests completed? Are appropriate frequencies tested? Condition of equipment? Lipscomb's 4-fold Analysis - answers-Is the causative factor sufficient to have caused the injury/loss? Is the hearing loss configuration consistent in the context of the alleged cause? Is the time-course consistent? Are the complaints consistent with the disorder? Elements of a Report - answers-History Physical Examination Audiological Examination Differential Diagnosis Prognosis Allocation Recommendations (tests, treatments, precautions) Job restrictions and Precautions IMPAIRMENT FORMULAS - answers-American Academy of Otolaryngology 1979 ( Threshold 500+1000+2000+3000 ) -25 X 1.5% 4 = % impairment for each ear. Hearing Handicap = 5(better ear) + worse ear/6 Decibel/Logarithm - answers-80dB + 80dB =? = 83 dB 130dB + 80dB = = 130dB 130dB has 100,000 times the power of 80dB The addition of 80dB is negligible Compensation of Witness - answers-An expert witness has a constitutionally protected property right (his or her expertise) and that it can not be taken without compensation. The expert witness is entitled to charge a reasonable fee for time spent reviewing, discussing reporting and testifying. Plaintiff or defendant, not attorney, is responsible for bill Establish terms early and in writing Hourly fee Retainer In advance Pay-as-you-go Cancellation fee Contingency fee - NEVER Compensation of Witness It is unethical for an - answers-expert witness to accept contingent fee arrangements in which compensation is linked to the outcome of a case. This arrangement would undermine impartiality and should be avoided (Dobie). Setting Your Fee - answers-Think about what you (your office) charges per hour, NOT what you personally earn per hour. While you are in court, researching, preparing reports, being deposed, you are not in your office providing billable audiological services. Cancellation fee appropriate if you set aside time in which patients were not scheduled. Non-occupational noise exposure - answers-Examples: Hunting/shooting Motorsports Power tools Music Nightclubs/bars Airports Day care centers Community noise - answers-Main sources of community noise include road, rail and air traffic, industries, construction and public work, and the neighborhood Typical neighborhood noise comes from: Premises and installations related to the catering trade (e.g. restaurants, cafeterias) Live or recorded music Sport events, including motor sports Playgrounds Car parks Domestic animals such as barking dogs Main indoor sources of noise are ventilation systems, office machines, home appliances, and neighbors Measuring community noise - answers-A-weighted measurements, unless it is impulse noise for which you would use C-weighted measurements 3 dB exchange rate Types of measurements: - answers-LAeq,T dBA = continuous equivalent sound pressure level LAN,T = sound pressure percentile level (e.g. LA10,18 hours) Lday Levening Lnight Ldn = Day-night average sound level system LAE dBA = sound exposure level LAeq,T dBA = - answers-continuous equivalent sound pressure level LAN,T = - answers-sound pressure percentile level (e.g. LA10,18 hours) Non-occupational noise standardsq - answers-Motor vehicles - Federal Highway Administration (2010) 1 hour equivalent time average sound level of 67 dBA is the criterion level If louder than this, noise barriers needed for new highway projects LAE dBA = - answers-sound exposure level Ldn - answers-Day-night average sound level system EQ - answers-equivalent level L - answers-time Local noise ordinances - answers-At the state and/or municipal level Based on perceived nuisance and/or sound level Nuisance is determined by two or more listeners' subjective determination Sound level is measured by SLM, but ordinances vary in which type of measurement is desired (e.g. average sound level over certain period of time, octave band measures, etc.) In US - max permissible levels vary from 45 dBA to 72 dBA Community measurement objectives - answers-The details of noise measurements must be planned to meet some relevant objective or purpose. Some typical objectives would include: Investigating complaints Assessing the number of persons exposed Compliance with regulations Land use planning and environmental impact assessments Evaluation of remedial measures Calibration and validation of predictions Research surveys Trend monitoring Case 1 - Code enforcement - answers-Complaint of noise nuisance from a night club A city contacted Dr. Rahe to measure the sound levels emitted from a night club adjacent to a residential area Neighbors had complained about the noises The city was interested to see if their noise ordinance was being violated Case 1 - Code enforcement Measurements: - answers-Inside club Outside door of club (open and closed) At property line 300' away in residential area 6:15PM, 11:45PM and 1:45AM Case 2 - Zoning issue - answers-Variance request to install a car wash The owner of a gas station came to the Board of Adjustment requesting a code variance in order to install a car wash Code requires that a car wash be at least 100' from a residential property line. Due to existence of other structures, car wash would be built 69' from property line Requested sound level output of car wash Code: Noise limits of most restrictive area must be applied. - answers-Code: Noise limits of most restrictive area must be applied. Residential code allows: 55dB A 10:00PM - 7:00AM 60dB A 7:00AM - 10:00 PM Specifications of car wash indicate that noise level at 70' (residential property line) would be 65-67dB, and at 100' would be 63dB. Petition was denied. Case 3 - Compliant to City Hall - answers-A local municipality obtained a Federal grant for playground equipment The equipment was installed in a small park in a residential area adjacent to the library One piece of equipment was a xylophone Neighbors complained to the City that the xylophone was played all hours of the day and was very disturbing Recreational noise exposure - answers-Shooting / hunting Typically 134 to 190 dBP dBP - peak sound pressure level of an impulse noise Any exposure above 140 dBP is not good for any amount of time (NIOSH, 1998) Music Recreational noise exposure reduce exposure for guns by - answers-Practicing outdoors Practicing alone Keep distance from other hunters Use smaller caliber and/or longer-barreled weapons Avoid modifying muzzles Use hearing protection!! Recreational noise exposure reduce exposure for music by - answers-Acoustic treatment of the venue Encouraging rest periods Display of current sound levels Hearing protection devices! Noise levels at home - answers-Ideally, noise should be kept below... 35 Laeq,16 dBA during day and evening 30 Laeq,8 dBA during night (inside bedrooms); peaks not to exceed 45 dBA Noise levels at home reduce exposure by - answers-Using sound absorbing materials within the home Minimizing noisy equipment Minimizing volume of entertainment devices (e.g. surround sound) Installing sound proof windows; sealing windows and doors; keeping them closed Wearing hearing protection devices Classroom noise - answers-ANSI/ASA S12.60-2010/Part 1 Standard indicates maximum 1-hour averaged background noise levels in an vacant (with furniture) classroom to be 35 dBA and 55 dBC For large areas (e.g. cafeteria), the maximum is 40 dBA and 60 dBC Reverberation time not to exceed 0.6 seconds in smaller spaces and 0.7 seconds in larger spaces at 500, 1000, and 2000 Hz Settings with hazardous noise PE / aerobics classes Industrial arts (e.g. printing, shop class, etc.) Agriculture (e.g. tractors, squealing pigs, chainsaws, etc.) Music Music and hearing loss - answers-Unlike industrial hearing loss, musicians' hearing loss may be asymmetric. Musicians' environment is rarely reverberant - reverberation is main source of symmetric loss Violinist or drummer the left ear is worse Flutist the right ear is worse Treble instrument players may have up to 8k Hz notch Incidence of PTS in musicians - answers-Classical: 50% Rock/Pop: 30% Regulations for faciliteis - answers-Action level = 85 dBA Criterion level = 90 dBA Exchange rate = 5 dB Hearing loss prevention - answers-Control the exposure levels Control sound levels at the source Practice mutes/pads during rehearsals Reduce force when playing brass instruments Propagate music toward the audience more Control sound levels in the pathway between the source and the musician Add acoustic panels in orchestra pits and rehearsal rooms Place louder instruments (e.g. percussion) on risers so that music flows over heads of the other musicians in front of them Place musicians out of the direct line of vocalist or directional instruments Provide quiet rest facilities and appropriate breaks Control sound levels at the level of the musician's ear canal Foam HPD Great for what musician - answers-percussionists IEM for musicians - answers-In-the-ear monitors (IEM) Custom earpieces, can be wireless Allow attenuation of the crowd up to 25 dB Musician can hear his/her own instrument over competing sounds Better than floor monitors as floor monitors' output is typically raised louder to overcome competing sounds, like the crowd Non-protective if musician sets the sound level to 90 dBA or higher Fetal development - answers-Peripheral auditory structures developed by 20 weeks gestation Fetal response to pure-tones begins around 500 Hz followed by lower frequencies (250 and 100 Hz) then higher frequencies (1000 and 3000 Hz) Womb attenuation - answers-Fetal sound isolation calculated as difference between SPL necessary to evoke a cochlear microphonic from fetus and from newborn lamb Results: 11.1 dB at 125 Hz 19.8 dB at 250 Hz 35.3 dB at 500 Hz 38.2 dB at 1000 Hz 45.0 dB at 2000 Hz Low frequency sounds travel through the fluid-filled womb with more efficiency Up to 5 dB attenuation for sounds less than 1000 Hz ~20-30 dB attenuation for sounds more than 1000 Hz Fetal sheep - Bone conduction hearing in utero - answers-Tested in 3 conditions with cochlear microphonics Head uncovered Head covered with neoprene hood Head covered with neoprene hood with ear holes cut out Results CMs were more sensitive with head uncovered than with hood or hood with ear holes Conclusion: principal transmission is bone conduction Noise effects on fetal sheep - answers-ABR and inner ear histology measures made to evaluate the effect of noise on the fetal sheep's auditory system Intense exogenous noise penetrated uterus of pregnant sheep Resulted in elevations of the ABR threshold 2-3 weeks after exposure In fetuses repeatedly exposed to noise, histology showed greater hair cell damage in the middle and apical turns of the cochlea was observed; basal turn was not damaged Fetal sound exposure - answers-Dominated by low frequency Energy above 500 Hz attenuated 40-50 dB Fetus detects vowels, not consonants Probably detects rhythmic patterns of music Infants show preference for mother's voice Indicates learning takes place in-utero Loud noise damages fetal cochlea in low frequency region Implications for fetal hearing conservation - answers-Recommendations from Sound Study Group (Graven, 2000) Pregnant women should avoid being in environments with low-frequency (<250 Hz) sounds greater than 65 dB Do not place headphones (or other sound devices) directly on the abdomen of the pregnant woman No need to purposefully add auditory stimuli, such as playing music, in the environment; maternal voice and noises are sufficient for development HCP Training Applicable standards - answers-OSHA - 1983b; 29 CFR 1910.95 Federal Railroad Administration - 2008; 71 FR 63123, Oct. 27, 2006, as amended at 73 FR 79702, Dec. 30, 2008 U.S. Navy - U.S. Navy and Marine Corps Public Health Center, 2008 Annual Employee Training - answers-Effects of noise exposure Hearing protection Increase motivation to protect hearing Consequences of noncompliance Audiometric testing and test procedures Noise standard Employers must provide - answers-Selection of at least one plug and one muff Expertise to counsel employees about which is best for their exposure, use, and care Protection that is comfortable and effective Effectiveness based on Noise Reduction Rating (NRR) Audiology role: Best practice - answers-Be sure attenuation ratings based on realistic estimates Be sure that HPD can be expected to provide same attenuation as manufacturer promotes when it is actually worn Be sure to show how to use properly to maximize protection Often, amount of noise reduction bears little relationship to noise reduction rating (NRR) given by manufacturer Fit individually or small groups Failure to properly fit and/or properly wear HPD probably leading cause of NIHL Follow 4 c's: comfort, convenience, communication, caring Common objections to HPD - answers-"I can't hear my co-workers." "I forget to put them in." "I don't need them! I'm used to the noise." "Hearing protectors are uncomfortable." "I can always get a hearing aid." I don't want to get the dirt from my hands in my ear." Individual Perceptions - answers-I won't get hearing loss." Believe noise is not loud enough to cause damage ...noise controls are effective ...s/he is not old enough ...chances are not likely as majority of people do not suffer NIHL ...noise will "toughen" ears "Hearing aids can fix my hearing." Believe hearing loss is not that serious "I can still get hearing loss even though I used earplugs." Believe that taking action may not lead to benefit "I won't be able to hear a warning signal if I use earplugs." Believe that HPD will prevent communication safety Influencing variables Internal triggers - answers-Tinnitus Hearing loss External triggers - answers-Requirement Media campaigns HC for the hearing-impaired worker Goal - answers-protect what hearing the worker has remaining Challenges for those with hearing loss: - answers-Hearing co-workers Hearing instructions Hearing machine noise Localization of sound How do we use HPD effectively and not reduce speech to an inaudible level? - answers-Use specialized hearing protectors Passive (non-electronic) with uniform attenuation Active (electronic) with amplification Earmuffs with communication features May be possible to wear hearing aids under earmuffs Motivating workers #1 motivating factor for a worker to participate in HCP is - answers-#1 motivating factor for a worker to participate in HCP is that it is required Training is more effective when personalized Needs assessment Relationship developed between instructor and learner Respect for learning style Personalize hearing loss - answers-Use personal examples to demonstrate the consequences of hearing loss Ask questions: "What is your favorite sound?" "What sound would you miss most if you couldn't hear?" "What sounds connect you to people and your environment?" Audiometric testing must be available at - answers-at no cost to employees who are exposed to 85 dBA or above for 8 hours TWA Required audiograms - answers-Baseline Annual Who is responsible fore the hearing conservation program - answers-Audiologist or physician must be responsible for program Employee should be referred for further evaluation if a medical problem is suspected and/or if there the results are questionable CAOHC - answers-Council for Accreditation in Occupational Hearing Conservation Council for Accreditation in Occupational Hearing Conservation history - answers-Formed in the mid-1960s In the 1970s helped develop guidelines for components of HCP and a national certification program for audiometric technicians Current courses and certificates available: Occupational Hearing Conservationist (OHC) Course Director (CD) Professional Supervisor (PS) Main objective: "...educate, inform and guide industry and those serving industry on successful implementation of occupational hearing conservation programs to prevent occupational hearing loss." Present day committee is made up of representatives from various organizations Audiometric monitoring - answers-Performed by audiologist or supervised technician Audiometer and environment must meet ANSI specs Test: 500, 1000, 2000, 3000, 4000, and 6000 Hz Although not required, test 8000 Hz to see if a "noise notch" recovers Audiometric tests - answers-Name and job classification Date of audiogram Examiner's name Date of last calibration Noise exposure of employee Ambient noise of test environment Baseline audiogram requirements* - answers-Employers must have baseline completed within 6 months of employees' first exposure at or above 8 hour TWA of 85 dBA Exception: If company uses mobile van, can delay baseline for one year Baseline tests must be preceded by 14 hrs of 'effective' quiet******** Use of hearing protection not always a good substitute for this, but can be used if there is no alternative Reference against future audiograms May be revised; done for each ear separately Automated testing technique often used (aka Bekesy audiometry) Video: Annual audiograms - answers-Must be provided within 1 year of baseline Enables employers to assess success of program or need for protective devices/administrative/engineering controls If change in hearing found, considered a standard threshold shift (STS) STS - answers-OSHA: "change in hearing threshold relative to the baseline audiogram of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear" Can use age correction If use age corrected STS, might miss progressing loss until it becomes significant problem OSHA appendix F, tables F-1 & F-2 Notify employee within 21 days Make proper referral if suspect medical condition Check noise exposure levels Fit or refit HPD Show employee how to use it Require employee to wear it Can retest within 30 days from date of first test, even if referring to outside source for retest Complete audiological evaluation when needed OSHA 300 Log - answers-Log of work related injuries Used to report changes in hearing Must be logged within 37 days or within 7 days of retest If the OSHA 300 Log is not needed, the record still needs to be maintained for the duration of employment + 6 months Audiometric monitoring - ototoxicity - answers-Drug-related damage to auditory/vestibular system Symptoms: Hearing loss, tinnitus, dizziness, discriminating speech in noise Best way to identify and prevent is monitoring May not always be able to prevent if life-threatening but may be able to minimize damage May provide physician opportunity to adjust treatment therapy to minimize damage Like industrial noise, identify early, get a baseline, monitor Baseline: Within 24 hours of administration of chemotherapeutic drugs or within 72 hours of antibiotics Retest prior to each dose of chemotherapy or 1-2 times/week for ototoxic antibiotics Retest for 6 months following completion of treatment as some ototoxins stay in system with delayed onset or progression Audiometric monitoring - ototoxicity test - answers-Serial pure tone audiograms Ultra-high frequency valuable Consider OAE & ABR as well What constitutes a significant threshold shift? - answers-Test/retest: >20 dBHL at one frequency or >10 dBHL at two consecutive frequencies Confirm with retest Be aware that test/retest with ultra high freq can vary (10-15 dB at 9k-14k Hz)—especially with young children Frequency of evaluation - answers-Entire program: annually Components: ongoing E.g. if an employee has an STS, this should be investigated to determine the cause; if it was poorly fit/used HPD, this should be addressed E.g. if an employee perceives his/her work environment to be louder than before, he/she should alert management so that noise measurements can be repeated Program evaluation - answers-Managers, HCP implementer/team, and individual employees are all involved in evaluating the program Basic components Evaluate whether or not regulations are being complied with Determine if there are any deficiencies in carrying out the program Quantify improvements Assess audiometric test results Evaluate overall program effectiveness Assess audiometric test results - answers-Compile audiograms Hold on to the first valid monitoring audiogram Chose a sample # of workers ("restricted database") Based on outcome sought Examine the average thresholds for the sample group for reliability if the data appears reliable, analyze it Evaluate overall program effectiveness NIOSH (1998) recommends two-step protocol: - answers-Evaluate the integrity of the audiometric data Done according to: ANSI Technical Report - Evaluating the Effectiveness of Hearing Conservation Programs through Audiometric Data Base Analysis (ANSI S12.13 TR-2002) *the last two slides Compare the rate of STS of noise-exposed workers to that of non-noise exposed people Age matched, within same company when possible An STS rate of 3% or less is acceptable (NIOSH, 1998) HCP Elements - answers-Noise survey and data analysis Noise control Hearing protection devices (HPD) Education and motivation Audiometric monitoring Record keeping Supervision Program evaluation Compliance documentation HCP Goals - answers-Sampling the workplace to ID which employees are at risk from noise Informing at-risk workers the results of their monitoring Allowing at-risk workers and/or supervisors the opportunity to observe when the noise measurements are taken Implementing an audiometric testing program Putting into practice hearing protection procedures Selecting hearing protection devices for individual needs and evaluating their effectiveness Managing data (sampling, audiometrics, etc.) Training workers Assessing DRC and Exposure - answers-Issues that increase complexity Single event peak readings may confuse measurement Use Time Weighted Avg (TWA) or Leq as peaks may overestimate exposure (need to use dosimetry) Non-occupational noise exposure can compound shifts in hearing thresholds (need to counsel about hearing as a 24hr concern) Impulse noise estimates - answers-Not atypical for impulse/impact noise exposure during work day, e.g., hammer Dosimeters not designed according to specs for measuring impulse noise—in fact, impulse noise may contaminate dosimetry Must estimate repetition rate of impulses, ie, repetitions per work day Mr. Miller question - answers-Steady state noise, 3 hours/day at 95 dBA H frame power press, 75,000 repetitions of punching sound each shift with peak level of 118 dBSPL Steady + Impulse Mr Miller answer - answers-Use "dose" formula Dose (%) = 100 * (C1/T1 + C2/T2 + Cn/Tn) Mr. Miller 100 * (3/4 + 75000/100000) 100* (0.75 + 0.75) 150% Estimating exposure cautions - answers-Day to day variability of work Equipment changes Maintenance problems Background noise variability Best way to assure exposure acceptable, audiometric monitoring Noise control - answers-Changes made to reduce the emitted noise level of a sound source to an acceptable level Generally left to engineers Provide accurate assessment of potential benefits and practicality of control Design and specifications Costs Other methods available to reduce exposure Benefits of noise control - answers-Reduced NIPTS Reduced compensation costs Improved communications Reduced absenteeism Reduced injuries Costs of noise control - answers-Depends on how much reduction in noise needs to occur and in what manner Feasibility Initially - "capable of being done based on cost-benefit analysis" Proposed meaning in 2010 - "capable of being done" (without threatening the viability of the business) Noise control options - answers-Engineering controls Source treatment Pathway treatment Receiver treatment Administrative controls Engineering controls - answers-Source treatment Modification Retrofit Substitution Relocation Alternatively, quieter equipment could be purchased source treatment modification - answers-Source treatment - Modification Modify mechanical impacts E.g. minimize distance between impacting parts Optimize high-velocity fluid flow E.g. eliminate sudden changes of direction Optimize high-velocity air flow E.g. change the air-pressure setting to as low a value as practical Modify surface areas E.g. add small openings to large, solid surfaces Source treatment - Retrofit - answers-Vibration damping Vibration isolation Silencers Dissipative - absorption; good for 500 Hz+ Reactive - reflection; good for <500 Hz Pneumatic or compressed air Source treatment - Substitution - answers-Replacing one piece of equipment with another that can do the same job, just quieter Typically costs more for the quieter piece of equipment Could also substitute parts/materials, not whole piece of equipment Source treatment - Relocation - answers-Moving the sound source to another area Pathway treatment - answers-Once all feasible options for controlling noise at the source have been implemented, treating the pathway from the source to the receiver would be the next option Typically 4 methods to treat the pathway: Adding sound-absorption materials to the area Installing sound transmission loss (TL) materials between the source & receiver Using enclosures and/or barriers Any combo of the first 3 Pathway treatment - Adding sound-absorption materials - answers-Used in a reverberant field & for those whose noise exposure comes from reverberant sound Typically added to walls and ceilings Helps absorb mid- to high-frequency sounds Only helpful if worker is not in line-of-sight direction of the sound source Pathway treatment - Installing sound TL materials between source & receiver - answers-Used to stop noise from traveling through a structure (e.g. a wall) Typically a dense material that can attenuate sound transmission are used on/in enclosure panels, windows, doors, etc. different materials will attenuate at different frequencies and to different degrees (typically 20-60 dB) Acoustical enclosures - answers-surrounds noise source Very common 20-40 dB noise reduction across many frequencies Usually reasonable cost Downside - access to the equipment is limited Acoustical barriers - partial partition - answers-Between source and receiver 15-20 dB noise reduction typical Receiver treatment - answers-When sound source and pathway treatment are not able to reduce the sound to a reasonable level, treating the receiver (worker) is an option Two methods: Build an enclosure for the worker Ideally so that the sound is 80 dBA or less within the enclosure Relocate the worker to a quieter area Administrative controls - answers-Rotate shift and/or workers on shift Job share Reduce 8 hour exposure how to reduce noise 3 ways - answers-Typically a combination of engineering and administrative controls are used to reduce noise dose Additionally, hearing protection devices can also be used Hearing protection device (HPD) standards - answers-OSHA standard 1983; 29 CFR 1910.95 Voluntary use 8-hour TWA noise levels of >85 dBA (employers must provide) Mandatory use 8-hour TWA of > 90dBA For any period exceeding 6 months after first exposure to >85 dBA for 8 hr TWA, until baseline audiogram conducted If have STS demonstrating susceptibility to hearing loss from noise HPD Styles - answers-Earplugs Semi-inserts Ear clips Earmuffs Helmets Earplugs Material - answers-Vinyl Silicone Elastomer formulations Slow recovery closed cell foam Spun fiberglass Cotton-wax Type of construction earplugs - answers-Custom Formable Pre-molded Roll down foam Semi-inserts (canal cap) - answers-Like earplugs, except they do not go deep into the ear canal There is a soft tip on a headband that blocks the EAC opening Used by people who only need occasional protection and/or who are unable/unwilling to wear earplugs Not as protective as earplugs or earmuffs Ear clips - answers-Earplug-like as well Replaceable foam that forms to the outer ear sits on a frame to goes over the ear Good for people with sensitive ear canals Earmuffs - answers-Rigid plastic cups with soft cushions that seal around the ear Easy to fit, but still must check for seal around ears Can be worn with hardhats Good protection, but can be hot Also, good for going in and out of high noise areas Visible to inspectors Can be worn with hearing aids Helmets - answers-Offer skull and ear protection Similar to earmuffs, except the ear cups are mounted to a helmet Military use especially with pilots, tanks (Non)Electronic HPD Electronic (Active) - answers-Manipulate the incoming sound via electronics Components typically include a microphone, circuit, and receiver Need a battery to operate More expensive Non-Electronic (Passive) - answers-Incoming sound is only reduced by the structural elements of the HPD No battery needed Less expensive More widely used The 4 Cs of hearing protection - answers-Comfort Convenience Communication Caring Fitting Considerations - answers-Physics of device and anatomic/physiologic limitations of ear Air leaks Must be air tight seal Fit contours of ear Leaks can reduce attenuation up to 15dB in broad range Vibration Plugs can vibrate when in ear creating piston like action in canal(seal/unseal)—can reduce low freq attenuation Muffs also can vibrate and lose seal Leakage often at 125Hz and below Physics - answers-Bone and tissue conduction Transmission via BC Generally 40-50 dB below level of AC sound (therefore, not a major concern) E.g. - at 1000 Hz, ear sensitivity is 60 dB poorer for BC than AC (Fig 2) Occlusion effect causes increased sensitivity Even when use muffs to reduce sound around skull, negligible effect (3-4 dB @ K) Only way to eliminate would be to completely enclose head/face Attenuation characteristics - Input dependent HPD - answers-HPD that change attenuation based on input level = Amplitude-sensitive (or input-level dependent) Soft or inaudible sounds made audible (amplified) Moderate level sounds (non-hazardous) not manipulated Loud level sounds (hazardous) are attenuated Electronic vs non-electronic Noise reduction rating (NRR) - answers-States ESTIMATED amount of hearing protection / reduction Measured in decibels Manufacturers are required to list this on the packaging of the HPD The higher the #, the greater the protection NRR Determined by... - answers-Human subjects tested in a simulated industrial room With ears open and then occluded At nine frequencies Completed 3 times per subject Experimenter fits the HPD Assessing HPD - answers-Individual fit testing Measure attenuation on the individual Train wearers in correct fitting procedures Identify failing or deteriorating protectors Document HCP effectiveness Real Ear Attenuation at Threshold (REAT) - answers-Difference between hearing threshold with and without HPD Typically measured in the sound field from 125-8k Hz Microphone In Real Ear (MIRE) - answers-Measure insertion loss by looking at SPL with and without HPD Can bring portable real ear system to factory to measure live (F-MIRE) Issues associated with HPD - answers-Poor training and motivation for proper use Differences between labeled NRR and achievable field attenuation Impaired communication when wearing Decreased localization, especially for earmuffs Tinnitus consideration - answers-In moderate noise levels, HPD may make tinnitus more apparent In high levels of noise, HPD may not change tinnitus perception as the noise that penetrates the HPD acts as a masker of sorts Performance in the "real world" - answers-Are plugs properly fit? In research, multi-sized plugs used to assure proper sizing Are employees inserting properly? Do employees wear eyeglasses with muffs creating leakage? Comfort is key. Real world employees will only use if comfortable Manufacturer's lab data good for research but may not be realistic for work Why HPD fail in the real world - answers-Comfort Utilization Fit Compatibility Readjustment Deterioration Abuse You have just contracted with a facility to manage their OSHA Hearing Conservation Program (HCP) As their audiologist, your job will be to: - answers-Take a noise survey at the facility Perform OSHA compliant audiograms on eligible employees Write a report to the owner with your findings Make recommendations so that they will be OSHA compliant As part of your recommendations, for each employee you will determine: Noise dose Time weighted average Presence of STS What is required in terms of HCP for each employee Criterion level - answers-The criterion level is the maximum allowable exposure to accumulated noise; it gives the conditions that result in 100% dose. The criterion level is typically set by a regulating agency such as OSHA and is usually not applicable for community noise monitoring Dose - answers-Related to the criterion level, a dose reading of 100% is the maximum allowable exposure to accumulated noise. For OSHA, 100% dose occurs for an average sound level of 90dB over an 8 hour period (or any equivalent exposure). By using a TWA reading rather than the average sound level, the time period is no longer explicitly needed. A TWA of 90dB is the equivalent of 100% dose. The dose will double (halve) every time the TWA increases (decreases) by the exchange rate. Exceedance levels - answers-Exceedance levels represent the percent of the run time that was spent at or above the corresponding dB level Exchange rate (doubling rate) - answers-Exchange rate refers to how the sound energy is averaged over time. Using the decibel scale, every time the sound energy doubles, the measured level increases by 3dB. This is the 3dB exchange rate that most of the world uses. For every increase of 3dB in the time weighted average, the measured DOSE would double. LAVG - answers-Lavg is simply the average sound level measured over the run time. This becomes a bit confusing when thresholds are used. Any sound below the threshold is not included in this average. When averaging decibels, short durations of high levels can significantly contribute to the average level. Remember LEQ and LAVG are equivalent when the exchange rate is 3 dB Threshold (cut off) - answers-All sound below the threshold is considered non-existing noise for the averaging and integrating functions. The threshold does not affect measurements in the sound level mode. The threshold affects the LAVG, TWA, and DOSE measurements. Max level - answers-The maximum level is the highest sampled sound level during the instrument's run time allowing for the RESPONSE that the unit is set for (fast or slow) and the weighting ("A" or "C"). Peak level - answers-Peak is the highest instantaneous and unweighted (linear) sound level that the microphone detects. Unlike the MAX LEVEL, the peak is detected independently of the slow or fast RESPONSE that the unit is set for. Response (Fast, Slow) - answers-The response determines how quickly the unit responds to fluctuating noise. Fast has a time constant of 125 milliseconds. Slow has a time constant of 1 second. Time weighted average (TWA) - answers-The time weighted average always averages the sampled sound over an 8 hour period. Weighting - answers-A", "B", "C", AND LINEAR are the standard weighting networks available. These are frequency filters that cover the frequency range of human hearing (20Hz to 20 kHz). Sound Measurement Principles Purpose - answers-To find out if a particular noise is hazardous To indentify and label noise hazard locations/equipment To know who is exposed to dangerous volumes of noise To compare noise levels to the regulation levels To know if a HCP is warranted To determine need for HPD and how much attenuation is needed To monitor changes To assist in workman's compensation claims To help researchers further understand threshold shifts and combined effects Noise - overview - answers-Factors that contribute to the overall noise exposure and subsequent changes in hearing: Temporal pattern Level of noise Frequency of noise Duration of noise exposure Indications of a problem - answers-Subjective responses to those in the noise Noisy conditions can make normal conversation difficult When noise levels are above 80 decibels (dB), people have to speak very loudly When noise levels are between 85 and 90 dB, people have to shout When noise levels are greater than 95 dB, people have to move close together to hear each other at all High noise levels can cause adverse reactions or behaviors Walk around survey purpose - answers-Screen for noise exposures sound level meter measurements estimates of the duration of exposure Readings can be used to determine the need for a more complete evaluation Determine if additional monitoring is necessary walk around survey for tour facility - answers-Develop understanding of facility operations Identify potential noise sources Look for indications that noise may be a problem Use sound level meter to take spot readings of any questionable areas Make notes of what equipment is on/off Estimate exposures Having the floor plan available to write/take notes on can be helpful If the results of the walk around survey indicate time weighted average (TWA) exposure of ______ then do what? - answers-80 dBA or more, then additional noise monitoring should be performed Remember to take into account the accuracy of the sound level meter when making this estimation why? - answers-Type 2 sound level meter has an accuracy of =/- 2dBA Noise dosimeter - answers-Used to track personal noise exposure and calculate noise dose Consists of a microphone and microprocessor Can select several settings Exchange rate Frequency weighting Fast or slow response Criterion exposure level Threshold Most can perform all the functions of a sound level meter Octave band analyzers - answers-Measure noise levels in separate frequency bands Used to analyze the frequency content of noise Some sound level meters (SLM) have an octave or one-third octave band filter attached or integrated into the instrument Usually type I (precision) SLM Most have filters with the following center frequencies: 31.5, 63, 125, 250, 500, 1000, 2000, 4000, 8000, and 16000 Hz Also valuable for calibrating audiometers and determining the adequacy of various types of noise controls Evaluating employees with sound-generating headsets - answers-Clerical personnel Aircraft pilots and other cockpit personnel Air traffic controllers Emergency personnel Reservation clerks Receptionists Disc jockeys Telephone operators Sound level meters (SLM) - answers-Measuring instrument for noise exposures Components include: Microphone Filter set Amplifier Display More on more sophisticated SLM Typically measure from 30-130 dBSPL SLM - additional features - answers-Calibrator / piston phone Octave band analyzer Impulse / impact noise analyzer Rise time that can capture peak energy Input / output capability Permits communication with other devices, e.g. tape recorder, printer International Electrotechnical Commission (IEC) - answers-Standards organization for all areas of electrotechnology American National Standards Institute (ANSI) - answers-Develops standards for the US Standards for SLMs: Now - answers-ANSI S1.4-2014 & IEC 61672:2013 Revises ANSI S1.4-1983 (R2006) / ANSI S1.4a-1985 (R2006) Gives details of tests necessary to verify conformance Ensures that periodic testing is performed in a consistent manner by all labs Issues with the IEC & ANSI standards - answers-Performance of meters seemed be designed to meet a specification designed by the manufacturer Manufacturer can state design goals in terms of "when tested in accordance with" a particular test procedure. Result: "design to pass the test" instead of "design to the intent of the specification" Poor specifications for response to transient signals Poor specifications for level linearity errors No specifications for peak sound level Wide tolerance limits do not reflect current technology for important characteristics SLM - ANSI types - answers-Type 0: Primarily laboratory and research use Type 1: Precision measurements meeting rigorous specs Type 2: General purpose Accepted by OSHA Adequate for most industrial sound measurements Type 3: Survey meters for nonprofessional, hobby-type use Not recognized by OSHA or ANSI Type 0 - answers-Laboratory standards Used to calibrate other SLMs Used for academic research Extremely high precision, more than needed for field use Type 1 - answers-Precision Used for field work More accurate then Type 2 with tolerances generally not exceeding 1 dB Commonly used Measurements accurate enough to be used as evidence in the resolution of legal disputes Type 2 - answers-General purpose Meets OSHA standards Excellent for monitoring A-scale measurements Can add additional features, e.g., Calibrator Octave band analyzer Impulse meter Time weighted averaging circuits Input/output devices Type 3 - answers-Noise survey meters & dosimeters Using a sound level meter - answers-Standard SLM has a free field microphone Intended to be held at arm's length and tipped up slightly towards the noise source If you are in a diffuse field, angle of mic is less important Try to avoid angling the mic toward reverberant surfaces Considerations include - answers-Time constants types impulses Weighting Filters Used to assess characteristics of noise OSHA requires _______ response be used for sound surveys - answers-slow OSHA requires _________ scale be used for sound surveys - answers-A Frequency weighting - A Scale - answers-Approximates the ear's response to moderate level sounds Simulates loudness annoyance Used in hearing conservation program measurements Frequency weighting - B Scale - answers-Accounts for more low frequencies Not widely used in hearing conservation Some newer sound level meters don't include this scale Frequency weighting - C Scale - answers-Approximates the ear's response to loud level sounds Close to linear with limited filtering Good for measuring peak SPLs of loud impulse noises Can be used along with A Scale to determine if there is significant low frequency energy in the noise being measured Octave band analysis - answers-Used when statement of total sound is not sufficient and there is need to know where sound energy is located (low/high Octave band analysis can help with - answers-Mechanical considerations HPD considerations Potential damage to hearing Room noise during audiological testing Audiometer calibration Frequency analysis - answers-measuring sound at different parts of frequency spectrum Use system of filters which only pass certain frequency bands Duration - Equal energy principle - answers-Overall energy = the SPL of the noise + amount of time exposed Overall energy amount determines the degree of biological damage the equal energy principle states - answers-that equal amounts of overall energy should cause the same degree of damage regardless of how the time periods of exposure are dispersed Duration - Exchange rate Definition - answers-The increase (or decrease) in decibels that requires halving (or doubling) of exposure time Trade-off between exposure level and exposure time Rationale for 5 dB exchange rate - answers-Proposals have ranged from 3 dB to 9 dB for exchange rate Dupont, which manufactured 1st sound level meters/dosimeters, were proponents of 5 dB Burns (UK) proposed 3 dB to recognize "power" doubling/halving Needed practical measurement scale Needed accepted measurement scale that could meet tolerances and capabilities of measurement tools Criterion sound level (LC) - answers-"The continuous equivalent 8-hour A-weighted sound level (as dBA) that constitutes 100% of an allowable noise exposure (dose) - in other words, the permissible exposure limit." Noise dose - answers-Looks at amount of noise exposure received relative to the amount of allowable exposure Calculated as a percentage A dose of 100% means you've reached the limits of allowable exposure When calculating noise dose, any level less than the threshold is not factored in Noise dosimetry problems - answers-Purpose: assess individual exposure Provides TWA sampling for Leq (minute-by-minute sampling) Limitations/warnings Placement of mic "horseplay" by employee Presence of impulse noise contaminating results Some are only "pass/fail", not actual readings Only reflects sound on that day Time weighted average (TWA) - answers-Shows a worker's daily exposure to occupational noise normalized to an 8 hour day (TWA8) Using noise dose, the equivalent TWA can be calculated: TWA = 16.61 log[D(%)/100(%)] + 90, dBA (OSHA) Leq(1) = 75, means... - answers-During 1-hour period, sound averaged 75dB Does not account for variations in sound If thresholds are used, this number may not be representative of the true average (e.g. office measurement) Provides way of predicting longer noise exposure when just sampling for 1-2 hours Lavg & Leq are functionally the same, except Leq is only - answers-used when the exchange rate is 3 dB and threshold is 0 dB TWA vs Lavg - answers-TWA is less than Lavg if the duration is less than 8 hours TWA is more than Lavg if the duration is more than 8 hours TWA is equivalent to Lavg if the duration is 8 hours osha standards are used to protect - answers-most workers but cant help them all C1 - answers-time exposed to a certain noise level T1 - answers-time aloud to be exposed to the noise level - answers- Damage risk criteria - answers-The risk of developing a defined level of hearing loss over a specified number of years for a given population exposed to a specific level of noise Damage risk criteria Variables - answers-Amount of allowed hearing loss Noise exposure Frequencies included Walsh Healy Act (1969)** - answers-Gave Department of Labor the right to regulate workers of companies that contract with the federal government Led to first federal noise standards Protection against effect of noise shall be provided when sound level exceeds permissible noise exposure (i.e., 90 dBA for 8hrs, etc.). Recommended 140 dB SPL max Feasible engineering/administrative controls shall be utilized or personal protective equipment An effective and continuing conservation program shall be administered Occupational Safety and Health Act (1970) - answers-Funding and research on occupational health and safety hazards Recommended safety standards Created NIOSH for research and OSHA for enforcement Also known as the Williams-Steiger Occupational Health Act (1971) mandated all workers be safeguarded from occupational hazards, including noise The regulators where did they come from - answers-OSHA NIOSH from Occupational Safety and Health Act. Noise Control Act (1972) - answers-Created by the Office of Noise Abatement (closed in 1982) Gave the Environmental Protection Agency (EPA) responsibility to regulate newly manufactured noise sources/equipment Label noisy products Develop public health and welfare criteria Educate public on hazards of noise Issued regulations on motorcycles, garbage trucks, trucks, air compressors OSHA Proposed Regulations (Oct., 1974) - answers-No worker should be exposed to steady-state sound exceeding 115 dBA or impact noise exceeding peak of 140 dBSPL Hearing tests for employees exposed to 8 hours with a TWA that is equal to or greater than 85 dBA Hearing protection during installation of engineering or administrative controls - answers-Needed to change noise standards Needed to write specific requirements for hearing conservation to give teeth to regulation Evidence to suggest 90 dBA was not sufficient to protect exposed population NIOSH (1972): Reduce to 85 dBA Require audiometric monitoring Hearing protection Employee notification Record keeping Hearing Conservation Amendment (1983)*** - answers-Cut and pasted Walsh-Healy into OSHA Specified what a hearing conservation program should be for manufacturing (separate regulations for mining and transportation) Provisions: 85 dBA/8hrs Employee monitoring and re-monitoring with new equipment Personal monitoring in noise varies over time Employees must be made aware of results of monitoring and personal test results Require baseline and annual audiograms (85 dBA) Tests supervised by audiologist/physician Adhere to ANSI test procedures HCA impact on industry - answers-When passed, little understanding of impact on industry, # of exposed workers, and/or degree of hearing loss Surveyors sent across the nation with sound level meters to sample plant noise and worker exposure BBN - Department of Labor Study XXXX - answers-OSHA wanted to know how feasible engineering noise controls would be to implement Bolt, Beranek, and Newman (BBN) - assessed available engineering controls (1976) Catalogued machines in general industry that needed noise control Evaluated how difficult it would be to decrease their volume Concluded that engineering / administrative controls could feasibly meet the stand of 90 dBA TWA for 8 hours for 99.4% of workers in general industry type jobs Booz, Allen, & Hamilton Study - answers-Similar to the BBN study and confirmed numbers of exposed workers BAH estimated cost to achieve 90 dBA by administrative/engineering $1351 / worker OSHA (1981) estimated cost for hearing conservation program $53 / worker Engineering control v. HPD + HCP - answers-Despite engineering controls being feasible, in the mid-1980s OSHA and the miners organization reversed the preferred hierarchy of controls OSHA said no citation for TWA of 8 hours at 100 dBA (policy CPL 2.45A CH-12) Risk assessment - answers-If higher frequencies and lower fences are used, the acceptable risk becomes more stringent, and a higher percentage of the population will appear to be at risk If there is to be no risk of hearing loss, the permissible 8-hour average would have to be 75 dBA The European Union has adopted 80 dB as its lower exposure Action Level Use of 5 dB exchange rate vs. 3 dB exchange rate US Dept. of Labor OSHA standards - Part 1910.95 ************ - answers-If an employee is exposed to an 8-hour time-weighted average (TWA) sound level of 85 dBA or greater then the employer must administer a hearing conservation program (HCP) ACTION LEVEL = 85 dBA If an employee is exposed to an 8-hour time-weighted average (TWA) sound level of 90 dBA or greater then the employer must administer engineering and/or administrative controls CRITERION LEVEL = 90 dBA Whether by HCP or engineering/admin controls, employee cannot be exposed to noises >90 dBA for TWA8 US Mine Safety and Health Administration (MSHA) - answers-Last updated noise regulations in 1999 - includes all types of miners as one group Regulation 30 CFR Part 62 PEL of 90 dBA 5dB exchange rate Action level of 85 dBA Differs from OSHA Dual hearing protection required when exposed to 105 dBA or greater Engineering noise controls mandatory at 90 dBA US Department of Transportation - answers-Federal Motor Carrier Safety Administration Noise regulation last updated in 2011 49 CFR 391.49 Max noise level of 90 dBA where driver sits Wiggle room of 2 dB - so enforcement begins at 92 dBA Hearing threshold level requirements Federal Railroad Administration Noise regulation last updated in 2006 49 CFR 227 Mostly similar to OSHA US Department of Energy - answers-Noise regulations protect all contractors working at DOE sites Noise regulation last updated in 2006 10 CFR 851.23 PEL of 85 dBA 3 dB exchange rate US Coast Guard - answers-Noise exposure guidelines for the crews aboard US commercial vessels Evaluation of 24 hour exposure levels Criterion level of 82 dBA Wearing of hearing protectors when level reaches 85 dBA Action level of 77 dBA US National Aeronautics & Space Administration (NASA) - answers-Noise regulations for all employees except those on space flights Criterion level of 85 dBA Action level of 82 dBA Exchange rate of 3 dB Primary reduction of noise by engineering / admin controls...rely on HPD only temporarily or those controls are not feasible US Department of Defense - answers-Provides instruction on noise exposure Last revised in 2010 DOD Instruction 6055.12 PEL of 85 dBA Exchange rate of 3 dB Peak sound pressure levels up to 140 dBC Requirements for ultrasonic exposure, noise assessment, & engineering control measures Primary reduction of noise by engineering / admin controls HCP Elements - answers-Noise survey and data analysis Education and motivation Noise control Hearing protection devices (HPD) Audiometric monitoring Record keeping Supervision Program evaluation Compliance documentation What monitoring does OSHA require? - answers-Employers must identify employees exposed to noise at or above 85 dBA over 8 working hours, or an 8 hr. TWA Exposure measurement must include all continuous, intermittent, and impulse noise within an 80 dBA - 130 dBA range and taken during typical work situation Monitoring must be repeated whenever changes in production, process, or controls change (increase) exposure Changes in the program (hearing protection, hearing tests, etc.) must reflect changes in noise exposure Employees entitled to observe monitoring procedures Employees must receive notification of results of exposure monitoring Employers must calibrate equipment used for monitoring according to that equipment's specifications What audiometric testing does OSHA require? - answers-Audiometric testing program must be implemented by the employer Audiometric testing must be available at no cost to employees exposed to 85 dBA or above for 8 hours TWA This testing provides an indication if hearing conservation program is effective in preventing hearing loss Audiologist or physician must be responsible for program Professional does not have to be available during actual testing Required audiograms: baseline and annual What does OSHA require after audiometric testing? - answers-Employer must notify any employee showing a STS within 3 weeks of known results Employer must fit or re-fit HPD for any employee showing a STS; unless related to a medical cause that resolves Any recommendations and/or referrals need to be made known to the employee Employer maintains record of baseline audiogram for duration of employee's employment Critique of OSHA & Hearing Conservation Amendment improvment - answers-Improvements Larger #s of people participating in HCP OSHA is reaching out and making changes working with Nat'l Hearing Conservation Association (NHCA) & NIOSH OSHA 300 Log requirement updated Issued bulletins on noise and hearing conservation Consensus standard offers more protection for construction workers Other regulators (e.g. MSHA) have made some improvements Advocacy is on the rise More is known about the combined effects of chemical and noise exposures Technological improvements in noise measurement equipment Education and training are more refined Critique of OSHA & Hearing Conservation Amendment - answers-Missed opportunities / Gaps Underserved workers HCA based on out-of-date standards Evaluation of HCP not required OSHA has relaxed its enforcement No citation until TWA exceeds 100 dBA European regulations surpass US regulations HPD are relied on heavily Critique of OSHA & Hearing Conservation Amendment How to improve hearing loss prevention - answers-Lower the criterion level to 85 dBA Remove the directive that 100 dBA is acceptable; impose engineering controls Label noisy equipment Regulate product noise emission Disseminate regulations for those industries that do not have them Revise HCA to have policies reflective of current research & resources Research effectiveness of HCP and make changes accordingly Surveillance - answers-There can be no effective program without knowledge of when, where and under what conditions cases occur US wo