HEARING CONSERVATION
PROGRAM
Date of Issue: 2007.04.02 Section: Hazard Assessment and Control
Issued By: Environmental Health &Safety Revision #: --
Part: Hearing Conservation Program
Revision Date: --
Pages: 20 Revised By: --
1.0 Introduction
The University is committed to promoting the health, safety and well-being of its workers, students, visitors and contractors, in accordance with the University of Calgary Occupational Health & Safety Policy.
The University has developed and implemented a comprehensive Hearing Conservation Program to protect University workers from hearing loss due to occupational noise exposure. The Hearing Conservation Program clearly defines and stipulates the responsibilities of all workplace parties involved in the development, administration and implementation of the program. The University strives to control excessive noise levels; however, certain operations and workstations may expose workers to significant noise levels.
The University is committed to the protection of workers from occupational hazards. Where feasible, workplace noise levels shall be minimized by engineering controls at the source, and/or administrative controls. As a last resort, personal protective equipment in the form of hearing protection devices will be required. Identified noise hazard areas shall be defined where the eight-hour TWA exceeds 85 decibel A-Weighting (dBA); the use of appropriate hearing protection shall be mandatory in these areas.
The Hearing Conservation Program includes the following elements:
1.0 Policy statement and legislated requirements; 2.0 Roles & Responsibilities;
3.0 Hazard identification, assessment and control;
4.0 Noise surveys, personal dosimetry and audiometric testing; 5.0 Worker education and training;
6.0 Recordkeeping; 7.0 Program review; and 8.0 Definitions & References.
1.1 Occupational Health & Safety Legislation
The University will meet or exceed the legislated requirements made under the Alberta Occupational Health and Safety Act, Regulations and Code. The University of Calgary has adopted the Alberta Occupational Health and Safety Code criterion level of 85 dBA, however all identified personnel who are regularly exposed to occupational noise levels at or exceeding the action level of 82 dBA Time-Weighted Average for a 8 hour shift (or 80 TWA for a 12 hour shift)
sound level, are to be included in the Audiometric Testing Program and will be required to participate in regular training and audiometric testing.
2.0 Roles & Responsibilities
2.1 Deans, Directors and Department Heads
• Ensure that the Hearing Conservation Program (HCP) and all its components are implemented, administered and enforced;
• Ensure potentially overexposed personnel attend HCP training and regular refresher training; and
• Ensure that all potentially exposed workers are provided with appropriate noise controls, including hearing protection, and audiometric testing.
2.2 Supervisors
• Notify Environmental Health & Safety of o noise concerns;
o identified potential noise hazards; and o workers who may be noise exposed.
• Notify Environmental Health & Safety of process, material or equipment changes that may alter noise exposures;
• Maintain an up-to-date list and/or map of noise hazard areas/operations and noise exposed workers;
• Identify and post warning signage outside entrances to the noise hazard areas. • Ensure noise-exposed workers have attended hearing conservation program training; • Ensure workers are trained in the proper use/fit, inspection and care and limitations of
their hearing protection devices;
• Ensure that workers properly use and care for hearing protectors;
• Take appropriate steps to minimize the risk of noise-induced hearing loss that may include implementing noise control measures, as well as the provision of hearing protection devices to workers, as required;
• Ensure that noise-exposed workers have received and participated in the audiometric testing program;
• Develop and implement the controls( Engineering, Administrative, PPE) necessary to prevent hearing loss; and
• Ensure that baseline testing is conducted for all workers who may be exposed to noise overexposures within the first six months of employment or exposure.
2.3 Workers
• Attend required training sessions on noise hazards, noise induced hearing loss and hearing conservation program;
• Wear hearing protection devices, where required (also applies to students, visitors and guests);
• Report noise hazards and hearing protector problems to the appropriate supervisor; and • Maintain hearing protectors in sanitary condition and proper working order.
2.4 Human Resources - Staff Wellness Centre
• Communicate any identified standard threshold shifts to the worker, via letter. Letter would include the results of the audiometric test, advise the worker to follow up with their family physician, and advise them of when they will need to undergo another audiometric test;
• If the audiometric testing results indicate that a specialist referral is required, the OHN will meet with the worker and advise them to see their family physician. With written consent from the worker, the results of the audiometric test will be provided to the worker's physician;
• Communicate to supervisors and EH&S which workers need audiometric testing and when each worker will need to be re-tested;
• Communicate any identified standard threshold shifts to the appropriate supervisor and EH&S, in the form of an annual aggregate report; and
• Maintain records of audiometric testing results, documentation of referrals, and reports. 2.5 Environmental Health and Safety (EH&S)
• Administer the Hearing Conservation Program; • Evaluate worker and work environment noise levels:
o Conduct noise exposure and survey assessments to determine if administrative and engineering controls are required, and how they will be implemented;
o Identify areas or processes that require noise attenuation and/or posting;
o Recommend feasible and practical noise control options;
• Periodically re-evaluate worker exposure, through the review of job profiles and associated processes, equipment, tools, and work tasks being used. In addition to changes in processes, tools or equipment, re-evaluation is required to help determine which job profiles need to be included in the Hearing Conservation Program;
• Provide technical services and advice regarding control measures, assist workers in the selection of appropriate protective devices and provide instruction on their use,
maintenance and care;
• Provide appropriate HCP training and education;
• Ensure that noise-hazardous equipment/areas are properly labelled or posted; and to
3.0 Hazard Identification, Assessment and Control
Sound vibrations travel through air, water, or solids in the form of sound waves. These waves are captured by the pinna of the outer ear and then transmitted through the auditory canal to the eardrum (Figure 1).
The eardrum vibrates in response to the pressure of the sound waves. The initial vibration causes the eardrum to be pushed inward by an amount equal to the intensity of the sound, so that loud sounds push the eardrum inward more than soft sounds. Once the eardrum is pushed inward, the pressure within the middle ear causes the eardrum to be pulled outward, setting up a back-and-forth motion.
Figure 1: Ear Diagram
The movement of the eardrum sets all three ossicles (hammer, anvil, and stirrup) in motion. The vibrating pressure of the stirrup (last ossicle) on the small opening leading to the inner ear sets the fluid in the cochlea in motion. The fluid motion causes a corresponding, but not equal, wavelike motion of the basilar membrane.
When the basilar membrane moves, it causes the small hairs on the top of the hair cells of the Corti to bend. The bending of the hair cells causes chemical actions within the cells themselves, creating electrical impulses in the nerve fibers attached to the bottom of the hair cells. The nerve impulses travel up the auditory nerve to the brain. Loud sounds cause a large number of hair cells to be moved and many nerve impulses to be transmitted to the brain.
A problem in any part of the ear may cause a hearing disorder or hearing loss. In general, hearing loss may be caused by a birth defect, an injury, or a disease.
3.1 Hazard Identification
Noise-induced hearing loss is one of the most common occupational illnesses; however it is often undetected because there are no visible effects. It usually develops over a long period of time and, except in very rare cases, there is no pain. A progressive loss of communication, socialization, and responsiveness to the environment occurs. In the early stages (when hearing loss is above 2,000 Hertz (Hz)) the ability to understand or discriminate speech is affected. As hearing loss progresses into the lower frequencies, it begins to affect the individual’s ability to hear sounds in general.
3.1.1 Types of Hearing Loss
The main types of hearing loss are conductive, sensorineural, or a combination of the two.
3.1.1.1 Conductive Hearing Loss
Any condition in the outer or middle ear that interferes with sound passing to the inner ear is classified as a conductive hearing loss. A conductive hearing loss can result from:
• Excessive wax in the auditory canal.
• A ruptured or heavily-scarred eardrum.
• Fluid in the middle ear.
• Dislocated or missing elements of the ossicular chain.
• Eustachian tube blockage.
• Otosclerosis (an abnormal growth of bone in the middle ear).
Work-related conductive hearing loss is not common, although it may occur occasionally as the result of accidents involving:
• An eardrum rupture or a break in the ossicular chain by a head injury.
• An explosion.
• A rapid pressure change in a decompression chamber.
• Penetration of the eardrum by a sharp object or fragment.
A significant number of conductive hearing losses are reversible through medical or surgical treatment.
3.1.1.2 Sensorineural Hearing Loss
Chronic noise-induced hearing loss is a permanent sensorineural condition that cannot be treated medically. "Sensory" hearing loss is associated with irreversible damage to the inner ear. The term "neural" suggests a degeneration of the neural elements of the auditory nerve. It is initially characterized by a declining sensitivity to high-frequency sounds, usually at
frequencies above 2,000 Hertz (Hz).
Animal research studies indicate that after moderate exposures to noise, subtle effects may be noticed, such as:
• Twisting and swelling of hair cells.
• Disarray of the cilia on top of the hair cells.
• Detachment of the tectorial membrane from the cilia.
• Reduction of enzymes and energy sources in the cochlear fluids.
These are conditions that would reduce the sensitivity of the hair cells to mechanical motion. The system at this point is in a state of auditory fatigue. In order to initiate neural activity, more acoustic energy must enter the cochlea than did before the noise exposure.
As the severity of the noise exposure increases, the following changes increase in degree and eventually become irreversible (Figure 2a and 2b):
• Hairs become fused into giant cilia or disappear
• Hair cells and supporting cells disintegrate
Figure 2a: Normal inner ear hair cells Figure 2b: Damaged inner ear hair cells
These damaging effects are increased in acoustic trauma, where a single noise exposure of relatively short duration but very high intensity occurs, such as an explosion. In this case, the system is vibrated so violently that its elastic limit has been exceeded. Attachments of the various elements of the organ of Corti are disrupted, hair cells are torn completely from the basilar membrane, and a temporary rupture of the reticular lamina may occur, allowing intermixture of fluids within the cochlea (poisoning those hair cells that may have survived the mechanical stress of the explosion).
3.1.2 Effects of Noise
The effects of noise can be simplified into three general categories, including primary effects, communication & performance effects and other health effects.
3.1.2.1 Primary Effects
The primary effects of excessive noise exposure may include:
Acoustic trauma refers to a temporary or permanent hearing loss due to a sudden, intense acoustic or noise event, such as an explosion.
Tinnitus describes the condition of "ringing in the ears." Individuals often describe the sound as a hum, buzz, roar, ring, or whistle. The inner ear or neural system produces the actual sound. The predominant cause of tinnitus is long-term exposure to high sound levels, though it can also be caused by short-term exposure to very high sound levels, such as gunshots. Non-acoustic events, such as a blow to the head, dietary issues, stress, jaw joint disorders, debris on the eardrum, or prolonged use of aspirin may also cause tinnitus. Many people experience tinnitus during their lives. Usually the sensation is only temporary;
however, it can be permanent and debilitating. Diagnosis and treatment of tinnitus can be difficult because it is a subjective measurement.
A noise-induced temporary threshold shift (NITTS) is a temporary loss in hearing sensitivity. NITTS may be the result of:
• The acoustic reflex of the stapedial muscle.
• Short-term exposure to noise.
With NITTS, hearing sensitivity will return to the pre-exposed level in a matter of hours or days, assuming that there is not continued exposure to excessive noise.
A noise-induced permanent threshold shift (NIPTS) is a permanent loss in hearing sensitivity due to the destruction of sensory cells in the inner ear. This damage can be caused by:
• Long-term exposure to noise.
• Acoustic trauma.
3.1.2.2 Communication and Performance Effects
The effects of excessive noise exposure on communication and performance may include:
• Difficulty understanding speech. • Annoyance.
• Difficulty concentrating. • Reduced efficiency. • Low morale.
• Adverse social behaviour. 3.1.2.3 Other Health Effects
Other effects of excessive noise exposure may include:
• Quickened pulse rate; increased blood pressure; and narrowing of the body's blood vessels as a result of noise may, over a long period of time, place an added burden on the heart.
• Abnormal secretion of hormones. • Muscle tension.
• Ulcers. • Loss of sleep. • Fatigue.
• Stress reactions. 3.1.3 Causes of Hearing Loss
Hearing loss may be categorized in terms of possible cause.
1. Presbycusis: Hearing loss from the natural aging process causes a gradual hearing decline. It affects the ability to clearly hear high-pitched sounds such as children’s voices, rustling leaves, and some musical instruments.
2. Noise-induced hearing loss:
• Industrial hearing loss: Loss caused by work-related noise exposure. • Sociacusis: Loss attributed to the noises of everyday life.
• Nosoacusis: Loss attributable to health deficiencies and diseases, including, hereditary progressive deafness, mumps, rubella, Meniere's disease, ototoxic drugs and chemicals, barotraumas and trauma from blows to the head.
3.2 Hazard Assessment
If there is a risk that workers may be exposed to noise at a work site in excess of 85 dBA Lex and
the noise exposure limits in Schedule 3, Table 1 of the Code, the supervisor must request that a noise assessment be conducted by EH&S at that worksite.
3.2.1 Survey Assessments
Noise survey monitoring with a sound level meter will be performed by EH&S, or their designate, utilizing a designed sampling strategy to:
• Determine the appropriate selection of hearing protection;
• Determine if the noise controls are working adequately to reduce noise exposures; and will
• Determine the need for cautionary signage. Survey monitoring will be repeated when:
• Any changes in production, process, equipment or controls occur which might render the hearing protection inadequate.
• Levels at or above the action level will require notification to EH&S and may initiate the implementation of worker noise exposure assessments.
• Identified ‘Noise Hazard” areas may require periodic reassessment (i.e. following changes in processes, or equipment).
Spot measurements will be collected in select locations within the work area(s)/room(s), and may be conducted for each identified area/room.
For example:
GENERATOR
3.2.2 Personal Noise Dosimetry
Personal noise dosimetry assessments include the following:
Representative noise exposure monitoring with a designed sampling strategy will be performed by EH&S or their designate to:
• Identify workers for inclusion in the Hearing Conservation Program; • Determine the proper selection of hearing protection; and
• Determine if the noise controls are properly working to reduce noise exposures. All continuous, intermittent and impulsive sound levels from 80 to 130 dBA will be integrated into the computation.
Monitoring will be repeated when:
• Any changes occur in the production, process, equipment or controls which might render the hearing protection inadequate; and
• At regular intervals for audit purposes.
Workers exposed at or above the action level will be notified of the results of the monitoring and included in the Audiometric Testing Program.
See Appendix II Personal Noise Assessment Cover Letter Template See Appendix III Personal Noise Dosimetry Record
Workers' noise exposure will be reassessed periodically as needed (i.e. following changes in processes, job responsibilities, or equipment).
Copies of the results of the noise exposure assessment will be provided and are available upon request by an affected worker.
3.2.3 Ototoxic Drugs and Chemicals
Ototoxic drugs and chemicals have the potential to cause damage to the inner ear structures which may result in temporary or permanent loss of hearing or an aggravation of an existing sensorineural hearing loss.
The supervisor is responsible for the identification of ototoxic drugs and chemicals in the laboratory. Supervisors must also ensure that personnel working with or around ototoxic drugs and chemicals are aware of the potential hazards, including the synergistic effect with noise, and must ensure that they adhere to the hazard controls which have been stipulated.
Additionally, supervisors are required to ensure their personnel are trained and competent in the use and control of such drugs and chemicals.
Workers also have a responsibility to communicate to their supervisor, the use of any prescribed medications or drug treatments that may be ototoxic.
See Appendix IV Safety Bulletin – Ototoxic Hazard Information 3.3 Hazard Control
There are various methods and equipment used to control noise in the workplace. The hierarchy of control that must be followed, as per the Alberta OH&S Code is as follows: Engineering,
Administrative and Personal Protective Equipment (PPE). In addition, substitution controls may be employed, as part of the engineering control measures.
3.3.1 Engineering Controls
The best method of dealing with noise in the workplace is to reduce the noise at the source through the use of engineering controls. Engineering controls can eliminate the need for hearing protection; audiometric testing, and other elements of a hearing conservation program. Even if noise cannot be reduced to safe levels at the source, reducing noise it increases the likelihood that hearing protection will be even more effective in reducing noise exposures below the 85 dBA exposure limit.
Whenever practicable, one or more engineered options for noise control reducing worker exposure levels below the legislated limit should be implemented. Some possible options include:
• Reduction at Source – Many potential noise problems can be solved by choosing quieter equipment. When new equipment is purchased, specifications should include either a limit on the noise, or a requirement for the supplier to provide noise performance data. If noise is not engineered out in the design stage, retrofitting existing equipment with noise control devices such as mufflers, silencers, special nozzles, or isolators can sometimes be effective in reducing the overall noise output.
o Acoustical baffles: Reflected sounds that are not absorbed will cause an increase in overall sound levels in a space. When the space is acoustically treated the sound build up is eliminated or reduced.
o Fan blade design: Fans are utilized frequently in industrial machinery as a vehicle to move air. If it is found that industrial fans are producing large amounts of sound, it is possible to achieve an 8-10 dB noise reduction by replacing straight fan blades with backward-curved blades.
• Enclosure of the Noise Source – Enclosing the noise source is especially useful when the enclosure doubles as a safety guard or as an environmental control device.
Enclosures reduce workers’ noise exposure by acting as a barrier and as a sound absorber. Noise reductions of 25 dBA are common with noise enclosures. The ceiling and walls should be lined with material that absorbs sound, otherwise noise will reverberate inside the enclosure and escape through small openings – often where workers are stationed. The size of all enclosure openings should be kept to a minimum. Machines that have solid safety panels can often be modified to convert the guarding into effective local noise enclosures.
o Engine Compartments: Engine compartments of trucks and buses can be lined with noise absorbents on the bulkhead and hood.
• Enclosure of Workers – Enclosing workers in a booth is practical when workers leave the enclosure only occasionally, for example, to make adjustments, or clear trapped material. Operator booths can achieve large reductions in noise levels; 20 dB is typical. • Acoustical Treatment of the Room – Lining the walls and ceiling with sound-absorbing
panels or hanging baffles reduces reflected noise effectively. This method doesn’t interfere with workers’ access to machinery or require special building structures;
however, close to the noise source the direct noise will remain a problem. Reductions of only 2-5 dB are typical when acoustical treatment of the room is used; the benefit of
acoustical treatment is that all workers in the room will experience these noise reductions.
• Separating the Worker from the Noise Source – Noise levels fall as the distance increases from the noise source. The rate at which noise is reduced with distance is increased with acoustical treatment of the room. When designing new facilities, this concept is practical when planning workstation locations.
• Combinations – Sometimes a combination of noise control methods is required to reduce noise. For example:
o Room treatment with a partial machine enclosure
After baseline data is obtained on worker noise level exposure, it is recommended that data be obtained on what machines produce the most noise, and if engineering controls are feasible options in workplace noise reduction.
If engineering controls are put in place, the noise reduction achieved should be measured and the results documented. This demonstrates compliance with noise control provisions of the regulations and may also be useful in solving other noise control problems.
3.3.2 Administrative Controls
Education and training are the primary administrative controls for hearing protection.
Administrative controls also include measures such as work-rest cycles, and infrequent work tasks. These controls are aimed at reducing the time a worker is potentially exposed to noise. 3.3.2.1 Warning Signs
Workplaces in which the noise level exceeds 85 dBA TWA will have signs posted. Signs shall read “Caution - Hearing Protection Required ". In extreme noise areas with measured noise
read “Danger – Hearing Protection Required”. levels greater than 105 dBA, signs shall
.3.3 Personal Protective Equipment
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reducing ability alone; it is determined by attenuation (or class) and the wearing time of th worker.
3.3.3.2 Hearing Classes
Hearing protection must be rated for the appropriate class as per the Code, Schedule 3, Noise; (Table 2, Selection of Hearing Protection Devices).
• Workers in designated noise areas must wear, at a minimum, Class “A” hearing
protection. Noise areas at the University of Calgary are defined as areas with measured noise levels greater than 85 dBA but not exceeding 105 dBA.
• Workers in designated extreme noise areas must wear “dual” hearing protection, consisting of Class “A” earplug and Class “A” or “B” earmuff. Additional administrative controls limiting the exposure time to keep the sound from reaching the worker’s ear drum below 85 dBA TWA must also be initiated. Extreme noise areas at the University of Calgary are defined as areas with measured noise levels greater than 105 dBA.
Another system of classifying hearing protection is the NRR or Noise Reduction Rating. This system uses a single number to express the attenuation of the protector. A rough comparison includes:
CSA Class NRR (approximate)
A 24+
B 17-24
C Less than 17
3.3.3.3 Code of Practice
In accordance with the Code of Practice for Hearing Protection, hearing protector devices will be available to all workers exposed to noise levels at or above the action level of 82 dBA Time-Weighted Average for a 8 hour shift (or 80 dBA TWA for a 12 hour shift) at no cost to the workers. Types of hearing protection include:
• Ear Muffs – fit over the whole ear and seal the ear from noise and are the most desirable form of hearing protection. NOTE: The efficiency of the muff type may decrease if the muff is not fitted properly or if glasses are worn with them.
• Ear Plugs – which are worn in the internal part of the ear and they are made of a variety of materials (rubber, plastic, or other material) that will fit tightly in the ear. Ear plugs are the least desirable type of hearing protection as they are less efficient and less hygienic. All contractors must also comply with this practice standard.
Proper initial fitting and supervision of the correct use of hearing protectors will be provided. For workers who have experienced a standard threshold shift, the attenuation must reduce the sound level to an 8-hour TWA of 85 dBA or less.
Re-evaluation of hearing protectors will be done whenever a workplace noise level increase renders the hearing protectors attenuation inadequate. Due to the nature of equipment and activities, noise levels may fluctuate and workers must be aware of the hazards that emit high levels of noise.
4.0 Hearing Evaluations
Hearing is evaluated by a board-certified audiologist. Hearing is measured with an audiometer which sends tones to each ear through headphones. During an evaluation, the worker must listen carefully and respond each time a tone is heard. The levels at which the tones are barely heard are the hearing threshold levels.
The audiogram chart records the thresholds
(measured in decibels) for tones at different pitches or frequencies (measured in Hertz). Normal
thresholds fall within the unshaded area on the chart. When hearing loss occurs, the threshold falls into the shaded areas, meaning sounds must be increased in level to hear them.
A baseline audiogram identifies the worker’s initial hearing status for comparison to future
audiograms. Periodic audiograms provide an update to determine if the hearing conservation program is effective and if non-noise factors are affecting hearing. A recheck audiogram or a professional referral may be needed if a significant hearing change occurs.
Periodic hearing evaluations illustrate how the worker’s hearing compares to normal for their age. They are the only way to determine whether hearing is being conserved. Unusual changes alert the worker and their supervisor to look for noise-related or medical causes before
permanent damage occurs. 4.1 Audiometric Testing
The University of Calgary will provide audiometric testing to all personnel who are identified as being regularly exposed to occupational noise levels at or exceeding the action level of 82 dBA Time-Weighted Average for a 8 hour shift (or 80 dBA TWA for a 12 hour shift) sound level. Every worker exposed to excess noise will be provided with:
a) An initial baseline audiometric test as soon as practicable, but not later than 6 months after the worker is employed or within 6 months exposure to excess noise due to a change in the worker’s duties or process conditions.
b) Not more than 12 months after the initial baseline test, and
c) At least every second year after the test in b) above.
Baseline audiograms will be preceded by at least 14 hours without exposure to workplace noise. This requirement may be met by wearing hearing protection which will reduce the worker's exposure to a sound level of 80 dBA or below.
Initial and annual baseline audiograms will be provided to workers whose job profile and noise exposure monitoring demonstrates that workplace noise levels continue to equal or exceed action level of 82 dBA Time-Weighted Average for a 8 hour shift (or 80 dBA TWA for a 12 hour shift).
Workers will be informed in writing within 21 days when an audiogram indicates a standard threshold shift which has been determined to be work related.
The Audiometric Testing program will be managed by Human Resources. 4.2 Hearing Aids
Permanent hearing loss isn’t magically “fixed” with a hearing aid. A hearing aid restores the audibility of human speech by amplifying the sounds picked up by the hearing-aid microphone. For severe hearing losses, this means amplifying all of the various speech sounds to a level that can be detected. In the case of mild-to-moderate degrees of hearing loss, the frequencies of the softer or missing speech sounds are selectively amplified. With hearing aids, familiar voices may not be immediately recognizable due to the additional frequency characteristics that become audible with the benefits of the amplification they provide.
For hearing losses due to noise or aging, the speech interference levels are usually in the 500-4000 Hz frequency range. The missing speech sounds are usually the high-frequency
consonants as opposed to the stronger vowel sounds. Speech becomes unclear and words may be misinterpreted. The discrepancy between hearing low- and high-frequency speech sounds accounts for why persons with hearing loss often hear only a portion of the speech message. If the phrase “take the fast car” is confused as “rake the back yard,” then the higher pitched sounds of t, f, s, and k must be amplified.
5.0 Education and Training
Workers must understand the nature of the noise hazard they are exposed to, and they must be made aware of how to protect their hearing. Annual training is required and will be provided for all workers who are exposed to noise at or above an 8-hour TWA of 82 dBA (or 80 dBA TWA for a 12 hour shift) and/or are required to work in areas with noise levels at or above 85 dBA. Training will cover the following information:
• The hazards of noise at work and at home, and the effects on hearing;
• Noise control strategies;
• Pertinent noise exposure and/or survey assessment results;
• The purpose and procedures of audiometric testing;
• The purpose, advantages, disadvantages, and attenuation of various types of hearing protectors;
• How to select the appropriate hearing protectors; and
• Instruction of proper fitting and care of protectors.
6.0 Record Keeping
A copy of the Hearing Conservation Program (including occupational exposure assessments) must be available to affected workers and government officers, upon request.
6.1 Noise Exposure Measurements
Noise exposure measurement records, such as noise surveys and personal dosimetry
measurements, must be retained by EH&S for as long as the University of Calgary operates; the records must include:
• The dates of measurements;
• The type of measuring equipment used; and
• The work location evaluated. 6.2 Audiometric Test Records
Audiometric test records must be retained by the University, for workers enrolled in the Hearing Conservation Program for a period not less than 10 years; the records must include:
• the name and job classification of the worker; • the date of the audiogram;
• the examiner's name;
• the worker's most recent audiogram; and
• the date of the last acoustic or exhaustive calibration of the audiometer and the measurement of the background sound pressure levels in the audiometric test rooms. Human Resources will retain the worker audiometric test results, documentation of referrals, follow up and any reports to supervisors and EH&S.
7.0 Annual Program Review
The Hearing Conservation Program will be reviewed regularly by EH&S or their designate to determine the following:
• the effectiveness of the education and training plan;
• to evaluate the need for further noise assessment; and
• to ensure adequacy of the noise control measures.
Environmental Health & Safety must retain the current copy of the Hearing Conservation Program.
8.0 Definitions
Action Level: the level of noise exposure at which:
• A worker must be enrolled in the Hearing Conservation Program and provided audiometric testing;
• Representative noise exposure monitoring is required by EH&S; and
• Hearing protectors and training on noise hazards must be provided to the worker. *The University of Calgary, Environmental Health and Safety department has set the current action level at 82 A-weighted decibels, or dBA Time-Weighted Average for a 8 hour shift (or 80 dBA TWA for a 12 hour shift).
Attenuation: a weakening in force or intensity, specifically related to noise levels.
Audiometric Test: a hearing test to determine the extent of any existing hearing loss and to monitor for on-going changes in hearing ability.
Audiologist: A professional specializing in the study and rehabilitation of hearing, who is
certified by the American Speech-Language-Hearing Association or licensed by a state board of examiners.
A-Weighted: The A weighting, expressed as dBA, is the scale used for most occupational noise measurements. The A weighting approximates the range of human hearing as it filters out lower frequency noises, which are not as damaging as the higher frequencies.
Baseline Audiogram: The audiogram against which future audiograms are compared.
Class “A” earplugs: Canadian Standards Association Class of hearing protection earplugs to reduce the effect of noise at a maximum equivalent noise level ≤ 105 dBA TWA.
Class “A” or “B” earmuffs: Canadian Standards Association Class of hearing protection earmuffs to reduce the effect of noise at a maximum equivalent noise level > 110 dBA TWA Æ to be worn in dual protection with the Class “A” earplugs.
Continuous Noise: Noise levels that vary with intervals of one second or less.
Decibels (dB): A measure of the sound level (loudness). The decibel scale is a logarithmic scale; as an example, a 90 dB noise is ten times louder than an 80 dB noise.
Frequency: The rate at which cycles of high and low sound pressures are produced by a source of sound. Frequency (Hz) is heard as the pitch of the sound. The human ear hears 20 to 20,000 Hz. Verbal communication is in the range 500 to 3000 Hz.
Hazard: is a situation, condition, process, material or thing that may cause an injury or illness to a worker.
Hearing Aid: an ear microphone used to restore the audibility of human speech by amplifying sounds.
Hearing Protection Devices (HPD): Personal protective equipment that is designed to be worn in the ear canal or over the ear to reduce the sound level reaching the ear drum. Examples include ear muffs or plugs.
Hearing Threshold Level (HTL): The lowest threshold that the worker can hear the test tone during an audiometric test. The HTL's are recorded on the worker's audiogram.
Hertz (Hz): A unit of measurement of frequency, expressed as cycles per second.
Impulse/Impact Noise: Noise that is a sharp burst of sound, generally less than one-half second.
Nasoacusis: is noise induced hearing loss attributable to health deficiencies and diseases, including: hereditary progressive deafness, mumps, rubella, Meniere's disease, ototoxic drugs and chemicals, barotraumas and trauma from blows to the head.
Noise: Unwanted sound.
Noise Dosimeter: An instrument worn by an individual that integrates the sound level exposure over a period of time.
Noise Induced Hearing Loss (NIHL): damage to the inner ear due to exposure to harmful sounds - sounds that are too loud or loud sounds over a long period of time.
Noise Induced Temporary Threshold Shift (NITTS): is a temporary loss in hearing sensitivity that will return to the pre-exposed level in a matter of hours of days, assuming there is no continued exposure to excessive noise.
Noise Induced Permanent Threshold Shift (NIPTS): is a permanent loss is hearing sensitivity due to the destruction of sensory cells in the inner ear.
Noise Reduction Rating (NRR): The Noise Reduction Rating of hearing protection devices (HPD) indicates the theoretical amount of reduction of noise levels that can be achieved if the HPD is worn correctly. This rating is shown on the HPD packaging.
Ototoxic: a hazard characteristic of drugs and chemicals that have the potential to cause damage to the inner ear structures which may result in temporary or permanent loss of hearing or an aggravation of an existing sensorineural hearing loss.
Pitch: Another term for sound frequency. Higher pitches are higher frequency sounds.
Presbycusis: a lessening of hearing acuteness resulting from degenerative changes in the ear
that occur especially in old age
Representative Exposure: Measurements of an worker's noise dose or 8-hour time weighted average sound level that is representative of the exposures of other workers in the workplace. Sound Energy: The amount of energy transmitted to the ear by noise.
Sound Pressure: Fluctuations in air pressure caused by noise; the louder the noise, the pressure greater the changes in air pressure. These fluctuations cause the ear drum to vibrate. Sound Level Meter: An instrument used for the measurement of noise in sound level surveys. Speech Interference Levels (SILs): The frequencies most associated with speech, which are the 500-4000 hz (frequency) range. Vowels (a, e, i, o, u) are low frequency sounds (below 2000 hz) and consonants (b, c, d, etc) are high frequency sounds. The low frequencies are the least affected by noise. If the high frequencies are affected, t's and p's or s's and f's may be easily confused.
Sociacussis: is noise induced hearing loss attributable to the noises of everyday life.
Standard Threshold Shift: An average shift from the baseline measurement in either ear of 10 dB or more at 2000, 3000 and 4000 Hz. These frequencies are the most important frequencies in communication and the most sensitive to damage by industrial noise exposure.
Supervisor: means an individual that directs or oversees a person, group, department, organization, or operation.
Time-Weighted Average (TWA) Sound Level: A measure of the total noise exposure over a specified period of time.
Threshold of Pain: A noise level of 120 dB causes pain.
Weighting Filters, Scales or Networks: Sound level meters and noise dosimeters use a selective weighting system (filters) to eliminate certain frequencies from the measurements that are unimportant in the noise exposure.
Worker: means any person engaged in work at the University of Calgary, including workers, contracted workers, volunteers, and graduate students.
9.0 References and Additional Resources
Alberta Occupational Health & Safety Act, Regulations & Code http://employment.alberta.ca/cps/rde/xchg/hre/hs.xsl/307.html
Bauman, Neil G., Ototoxic Drugs Exposed, Second Edition, GuidePost Publications, 2003.
Occupational Health & Safety Administration, U.S. Department of Labour website on Noise and Hearing Conservation. http://www.osha.gov/dts/osta/otm/noise/health_effects/ Retrieved Jan. 5, 2007.
Ototoxic Drugs, Chemicals and Heavy Metals in the Workplace, Dr. George Cook, Workplace Group. http://www.workplacegroup.net/article-drugs-chem-metals.htm Retrieved Jan. 5, 2007.
APPENDIX I
CODE OF PRACTICE
FOR HEARING PROTECTION
Date of Issue: 2005.06.24 Section: Hazard Assessment and Control
Issued By: Environmental Health &Safety Revision #: 1
Part: Code of Practice
Revision Date: 2007.01.03
Pages: 3 Revised By: CF
The following elements are required for establishing, implementing, and maintaining hearing conservation in the workplace.
RESPONSIBILITIES
Supervisors must implement a written hazard control plan in identified noise hazard work areas that informs and trains workers concerning:
1. Hazards present in the area.
2. Retain training records and all documentation.
3. Implement the rules and standards of the University of Calgary and the Alberta Occupational Health and Safety Act, Regulation and Code.
4. Ensure the availability and proper use of appropriate personal protective equipment and relevant health and safety reference materials.
Workers must
1. Follow all health and safety standards, rules and regulations. 2. Report all hazardous conditions to the supervisor immediately. 3. Wear or use prescribed protective equipment.
TRAINING
All noise-exposed workers and their immediate supervisors must have training in the following:
• Hearing Conservation course provided by EH&S.
• Individual counselling will be completed at the review of the audiometric testing by Human Resources.
HAZARD COMMUNICATION AND HAZARD ASSESSMENT
The University is committed to the protection of workers from occupational hazards. Where feasible, workplace noise levels shall be minimized by engineering controls at the source, and/or administrative controls. As a last resort, personal protective equipment in the form of hearing protection devices will be provided. Identified noise hazard areas are defined where the eight-hour TWA exceeds 85 dBA; in these areas, the use of appropriate hearing protection shall be mandatory.
Work areas identified or suspected of noise levels exceeding 85 dBA 8-hour time-weighted average (TWA) will have periodic noise level surveys conducted by EH&S. This monitoring may
alter the noise exposure of any employee. When levels exceeding 85 dBA TWA are found, all reasonable efforts will be made to use engineering and/or administrative controls to reduce the area noise. Work areas that are identified as exceeding 85 dBA TWA require external signage.
The posted signage must state the following:
CAUTION
Hearing Protection Required.
In extreme noise areas with measured noise levels greater than 105 dBA, signs shall read “Danger – Hearing Protection
Required”.
The University will meet or exceed the legislated requirements made under the Alberta Occupational Health and Safety Act, Regulations and Code. The University of Calgary has adopted the Alberta Occupational Health and Safety Code criterion level of 85 dBA, however all identified personnel who are regularly exposed to occupational noise levels at or exceeding the University of Calgary action level of 82 dBA Time-Weighted Average for a 8 hour shift (or 80 dBA TWA for a 12 hour shift) will be included in the Hearing Conservation Program (HCP) and must participate in audiometric testing.
HEARING PROTECTION
If reductions in noise levels and exposure times have not reduced worker exposure below the stated Occupational Exposure Levels (OELs), then appropriate hearing protection must be provided to those workers. Hearing protection must be selected to meet the Alberta
Occupational Health and Safety Code – Part 16 Noise Exposure.
1. All hearing protection shall meet CSA standard “Hearing Protection Devices – Performance, Selection, Care and Use” – Z94.2-02, “Hearing Protection”
2. Hearing protection must be rated for the appropriate class. (Schedule 3, Noise; Table 2, Selection of Hearing Protection Devices).
i. Workers in designated noise areas must wear Class “A” hearing protection. Noise Areas at the University of Calgary are defined as areas with measured noise levels greater than 85 dBa but not exceeding 105 dBA.
ii. Workers in designated extreme noise areas must wear “dual” hearing protection, consisting of Class “A” earplug and Class “A” earmuff. Additional administrative controls limiting the exposure time to keep the sound from reaching the worker’s ear drum below 85 dBA TWA must also be initiated. Extreme noise areas at the University of Calgary are defined as areas with measured noise levels greater than 105 dBA.
3. Due to the nature of equipment and activities, noise levels may fluctuate and workers must be aware of the hazards that emit high levels of noise.
4. Workers must be aware of the noise hazards within their work areas, as many workers conduct activities in more than one area.
5. All contractors and/or sub-contractors must comply with this practice standard. 6. During emergencies, workers may not enter identified noise hazard areas without the
appropriate hearing protection.
AUDIOMETRIC TESTING
The University of Calgary will provide audiometric testing to all workers as per the requirement of the Alberta Occupational Health & Safety Code Part 16 Noise Exposure.
The guidelines for audiometric testing are:
• Every worker exposed to excess noise will have a baseline audiometric test within 6 months of being so exposed.
• Again within 12 months of the initial baseline test, and
• Subsequently within each 24 month period thereafter, unless observations require more frequent testing.
Human Resources will maintain worker audiometric testing records indefinitely.
USE, CARE AND MAINTENANCE OF HEARING PROTECTION EQUIPMENT
Follow the manufacturer’s specific instructions for use, care, and maintenance of hearing protection equipment.
DEFINITIONS
Audiometric Test – is a hearing test to determine the extent of any existing hearing loss and to monitor for on-going changes in hearing ability.
Class “A” earplugs – Canadian Standards Association Class of hearing protection earplugs to reduce the effect of noise at a maximum equivalent noise level ≤ 105 dBa TWA.
Class “A” or “B” earmuffs – Canadian Standards Association Class of hearing protection earmuffs to reduce the effect of noise at a maximum equivalent noise level > 110 dBa TWA Æ to be worn in dual protection with the Class “A” earplugs.
Hazard – is a situation, condition, process, material or thing that may cause an injury or illness to a worker.
Hearing Protector – is a device that is worn to reduce the effect of noise on the auditory system. Supervisor – means the individual that directs or oversees a person, group, department,
organization, or operation from the University of Calgary.
Worker – any person engaged in work at the University of Calgary, including employees, contracted workers, volunteers, and graduate students.
APPENDIX II
PERSONAL COVER LETTER
TEMPLATE
Template Date of Issue: 2007.01.31 Section: Hearing Conservation Program
Template Issued By: Environmental Health &Safety Template Revision #: --
Part: Records
Template Revision Date: --
Pages: 1 Template Revised By: --
dd/mm/yy
Dear: Worker Name
We are pleased to provide you with your individual noise exposure assessment, which was conducted between dd/mm/yy and dd/mm/yy.
Your average level of noise exposure over an 8 hour period, on the date of assessment was ## Lex
decibels Type A (dBA). Our sampling and records indicate that you are /are not momentarily exposed to sound levels above 85 dBA; therefore wearing hearing protection is mandatory when you are working in an identified noise area or conducting activities with noise levels above 85 dBA.
Based on the noise assessment, the overall exposure rates of your work group, and the University of Calgary Hearing Conservation Program action level of 82 dBA Time-Weighted Average for a 8 hour shift (or 80 dBA TWA for a 12 hour shift), you have /have not been enrolled in the University of Calgary Hearing Conservation Program.
With your assistance, we were able to meet the University and regulatory requirements.
Thank you for your participation.
Regards,
Environmental Health & Safety
NOTE:
Enrolment in the University Audiometric Testing Program requires regular audiometric (hearing) tests at the following intervals:
• Within the first 6 months of employment and/or exposure (Baseline Audiogram)
• Within 1 year of the baseline audiometric test; and • Every two years thereafter.
APPENDIX III
PERSONAL NOISE DOSIMETRY
RECORD
Template Date of Issue: 2007.01.31 Section: Hearing Conservation Program
Template Issued By: Environmental Health &Safety Template Revision #: --
Part: Records
Template Revision Date: --
Pages: 1 Template Revised By: --
DATE OF ASSESSMENT: dd/mm/yy __/__/__
NOTE: If dosimetry testing was not conducted, please indicate the rationale and study group used to determine assessment into the hearing conservation program:____________________________________________________________________ NOISE ASSESSMENT CONDUCTED/REVIEWED BY: _______________________________________
Individual Dosimetry Test Results
Not Applicable █Instrument Calibration: Yes No N/A
Pre-Survey: dd/mm/yy: __/__/__ Calibrated to 114 dB?
Post-Survey: dd/mm/yy : __/__/__ Calibrated to 114 dB?
Comments: Test Results:
Session Start: Session End: Run Time: __________hrs
Slow Level Range (dBA): Min: Max: Overall Lex (dBA):
Assessment: Yes No N/A
Overall Lex > Action Level?
Slow Max Level > 82 dBA?
Require Hearing Conservation Education & Training? Require Enrolment into the Audiometric Testing Program?
Group Dosimetry Test Results
Not Applicable █Group/Job Function:
Shift Length: 8 hours ____ Hours
Group Assessment: Yes No N/A
Overall Lex > Action Level?
Slow Max Level > 82 dBA?
Require Hearing Conservation Education & Training? Require Enrolment into the Audiometric Testing Program?
Hearing Conservation Assessment:
Not Applicable █Hearing Conservation Assessment: Yes No N/A
Require Hearing Conservation Awareness and Training? Require Review of Code of Practice
Require Training on the Proper Installation and Use of Hearing Protection?
Enrolled in Audiometric Testing Program? If yes, forward to Human Resources and
Supervisor for audiometric testing.
Signatures
Worker Name: Test Conductor/Reviewer Name:
Date: Date: Signature: Signature:
APPENDIX IV
OTOTOXIC HAZARD
SAFETY BULLETIN
Date of Issue: 2007.02.01 Section: Hearing Conservation Program
Issued By: Environmental Health &Safety Revision #: --
Part: Appendix
Revision Date: --
Pages: 1 Revised By: --
Hazard Assessment
Ototoxic drugs and chemicals have the potential to cause damage to the inner ear structures which may result in temporary or permanent loss of hearing or an aggravation of an existing sensorineural hearing loss.Drugs and chemicals can effect auditory brainstem response results, demonstrate balance and equilibrium problems, result in abnormal acoustic reflexes, demonstrate hearing loss initially above 8K Hz, often do not show recruitment and are capable of demonstrating measurable auditory processing difficulties to staggered word tests. Tinnitus is often present and may disappear or be reduced when medication or exposure ceases.
The supervisor is responsible for identifying ototoxic drugs and chemicals in the laboratory and must ensure workers are trained and competent in their use and control. Personnel working with or around ototoxic drugs and chemicals must be aware of the potential hazards, including synergistic effect with noise, and adhere to the hazard controls stipulated by their supervisor.
Workers also have a responsibility to communicate to their supervisor their use of prescribed medications that are classified as ototoxic.
Ototoxic Classes
The main ototoxic drug classes include: Aminoglycoside as antibiotics (Gentamicin, Kenomycin, Neomycin), Salicylates as aspirin, Quinines, Loop diuretics, Anti-neoplastics as anti-cancer drugs (Cisplantin), and others, non-steroidal inflammatory, antibiotics, antihistamines, cardiovascular, anti-convulsant, anti-depressant and anti-psychotic drugs.
Some ototoxic chemical classes include: gas (Carbon Monoxide), heavy metals (Lead, Arsenic, Mercury, Manganese, Organotins (Trimethyltin (TMT), Tridthyltin (TET)), and organic solvents (carbon disulphide, trichloroethylene, styrene, xylene, and toluene).
Synergistic Effects
Documented evidence has shown that noise acts synergistically with certain drugs and chemicals. Noise and drugs (chemicals) have been shown to be synergistic in their damaging effects to the
balance/hearing mechanisms. Synergistic damage is multiples of the expected damage of either agent alone.
One synergistic example:
Noise Alone 4.1 risk factor Toluene Mixture Alone 5.0 risk factor
