Objective Science of Hearing Hearing Conservation Program Hearing Loss & Effects of Noise on Hearing Hearing Protection Devices Noise Reduction Rating Hearing Protectors & Care and Maintenance Audiometric Testing Research Safety, PI/Supervisor, & Employee Responsibility Recordkeeping Introduction

OSHA 29 CFR is the Occupational Noise Exposure Standard which mandates employers to protect employees against the effects of noise exposure when the sound level exceeds an 8 hour time- weighted average (TWA) sound level of 85 decibels measured on the A scale (slow response). Our goal at Clemson University is to identify noise hazards and protect employees from noise induced hearing loss. Objective

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Sound waves enter the ear canal and the eardrum vibrates. Vibrations pass through 3 connected bones in the middle ear. In the inner ear, moving fluid bends thousands of delicate hair-like cells that convert vibrations into nerve impulses. Nerve impulse are carried to the brain by the auditory nerves. The brain converts these impulses into what we hear as sounds.

Clemson University’s Hearing Conservation Program is implemented whenever employee noise exposures equal or exceed an 8 hour TWA of 85 decibels without reduction from the use of hearing protectors. Noise is measured using a dosimeter in units called decibels or dB. Hearing Conservation Program Noise Dosimeter

Strong vibrations from very loud noise can damage hearing. Hair-like cells are flattened. Once hearing is damaged, it cannot be repaired or replaced. How is Hearing Damaged

Noise Exposures Types of Noise: Pitch Loudness Whisper – 20 dB Normal conversation – 60 dB Concerts – 110 dB Gun Shot – 140 dB

Noise Induced Hearing Loss Constant exposure over a period of time Exposed to sound level over 140 db Tinnitus Temporary Hearing Loss May be caused by exposure to loud noises for a few hours. Hearing is restored after a period of time away from noise source. Permanent Hearing Loss May occur after the ear has been continually exposed to excess noise Hearing will not be restored and cannot be repaired Age Induced Hearing Loss Exposure to high sound levels Hereditary Nerve Damage Types of Hearing Loss

Temporary Threshold Shift Muffled sound after noise exposure If overexposure continues, shift may worse and become permanent May result in untreatable damage to hearing Tinnitus Ringing or roaring in the ears If overexposure continues, ringing may become permanent Symptoms of Overexposure to Noise

Frequency – how often exposed? Intensity – how loud is the noise? Duration – how long exposed? Individual Variability such as differences in individual “resistance.” Other Factors such as diseases, genetics, lifestyle, age, etc. Factors Affecting Hearing Loss

Engineering Controls Reduce noise at the source. Interrupt the noise path. Reduce structural vibrations. Administrative Controls Limit noise exposure. Rotating employees though high level noisy areas. Modify existing machinery. Place noise limit specifications on new equipment. Increase distance between employee & noise hazard. Personal Protective Equipment (hearing protection devices) Should reduce employee noise exposure below 8hr TWA of 90 dB. Noise Control

Voluntary Use Employee exposed to an 8 hour time weighted average (TWA) of 85dB. Employee exposed to levels < 85 dB for an 8 hr TWA but may work intermittent activities or equipment where sound levels could exceed 90 dB. Mandatory Use Employee exposed to an 8 hour TWA of 90dB. Employee exposed to an 8 hour of 85 dB but have not had a baseline hearing test. Employee who has suffered standard threshold shift (STS) hearing loss and are exposed to an 8 hr TWA of 85dB. Hearing Protection Use

Ear Muffs Ear Plugs Canal Caps Hearing Protector Devices

The noise reduction rating or NRR is a laboratory estimate of the amount of reduction achieved by 98% of users when properly fit. The NRR for each type of hearing protection will be printed on the package. The higher the number, the greater the protection. Noise Reduction Rating

Advantages Provide more consistent protection than plugs One size fits most heads Easy to put on and take off Disadvantages Heavier than ear plugs May be uncomfortable in hot environments Eyeglass wearers may not get a good seal May be expensive May vibrate at lower sound frequencies (<400 Hz) Ear Muffs

Inspect for cracks, tears or other signs of wear. Choose eyewear with thin temples so they don't interfere with the seal. Move hair away from your ears. Center the ear muffs over your head and make sure the seal is tight. Adjust the headband so the ear muffs are resting comfortably on your head. The cups should be entirely cover your ears. Wearing Ear Muffs

Care & Maintenance Clean ear cushions and headband regularly with mild soap and water Replace ear cushions and foam inserts approximately every 4 to 6 months or more often if heavy use Do not overstretch headbands Ear Muffs

Advantages Light weight Can be worn without interference from eyeglasses, headgear, earrings or hair Comfortable in hot/humid environments Less expensive than ear muffs Disadvantages Noise reduction highly depends upon a good fit Some people find them uncomfortable to wear for long periods of time Ear Plugs

Wash your hands. Inspect the ear plugs. Roll the plug between your fingers and thumb, making sure there are no wrinkles or creases in the plug. Reach one hand behind your head and pull your ear outward and upward to widen the auditory canal. Insert the plug well into the ear and hold it in place until it expands. Inserting Foam Ear Plugs

Care & Maintenance Dispose of single-use earplugs daily If multi-use earplugs, clean with mild soap and water and dry thoroughly If multi-use earplugs, inspect for dirt, cracks, hardness and replace as necessary Ear Plugs

Advantages Ideal for situations where hearing protection must be taken on and off frequently. Disadvantages They DO NOT extend into the ear canal, only close the ear opening. They are NOT designed for continuous, long-term wearing. They do not give you as much protection as ear plugs or ear muffs. Canal Caps

Wash your hands Reach one hand behind your head and pull your ear outward and upward to widen the auditory canal. Insert the tip of the cap into the ear, firmly pushing and wiggling them into place Canal Cap Insertion

Care & Maintenance Clean and replace pods regularly Do not overstretch band Canal Cap

After a few minutes of unprotected exposure at noise levels above 115dB, you may risk hearing damage. Ear plugs not properly inserted into the ear canal will not provide complete protection. Likewise, ear muffs not snug against the head will leak noise into the ear. Proper Use of Hearing Protection

In extreme environments, dual protection is frequently recommended To estimate the protected noise level, add about 5dB to the higher NRR protection device number. For example if you have earplugs with an NRR of 33 and earmuffs with an NRR of 29 the total maximum protection would be 38dB. Example: Earplugs = NRR 33…..add 5dB = 38dB Protection Level Earmuffs = NRR 29 Dual Hearing Protection + Earplugs NRR 33 Earmuffs NRR Total Maximum Protection = 38dB

Employees enrolled in the Hearing Conservation Program must participate in annual audiometric testing. Audiometric testing consists of measuring an employee’s hearing threshold initially to determine a baseline and annually to ensure there are no changes. Testing is provided to the employee at no charge. Audiometric Testing

Review and update Hearing Conservation Program Conduct noise surveys of the Clemson University work environment Determine the need for hearing protection Provide training to personnel on the proper use, maintenance and storage of heating protection Research Safety Responsibilities

Help identify potential noisy areas of concern and document areas of excessive noise. Assist Research Safety in identifying employees who are over the Action Level or may be exposed to noisy areas and equipment Maintain a list of employees who need hearing protection and ensure they are enrolled in the Hearing Conservation Program, given training, and provided with audiometric exams. Provide hearing protection devices to employees Post areas of known noise hazards with signs requiring the use of hearing protection PI/Supervisor Responsibilities

Understand the need for hearing protection devices Wear hearing protection devices and follow good care and maintenance Attend all scheduled audiogram appointments Communicate with supervisors about loud equipment or areas or any problems deserved Employee Responsibilities

Noise monitoring results are maintained by the Office of Research Safety Audiometric test results are maintained by the Occupational Health Nurse Job assignments and noise exposure history are also maintained by supervisors and the Office of Research Safety Records are available to individual employees upon request Recordkeeping

If you have any questions regarding the content of this training or general questions regarding hearing conservation, please feel free to contact the Research Safety Industrial Hygiene team. Anne Kogut | Industrial Hygiene Manager (352) Naomi Kelly | Chemical Hygiene Officer (864) Candis Duncan | Industrial Hygiene Specialist (864) Office of Research Safety 114 Long Hall Clemson, SC Contacts