HEARING LOSS Hearing Protection Devices (HPDs) are one component of an effective hearing conservation People living near airports or freeways program. HPDs can protect the delicate hearing HEARING are exposed to levels of noise typically system from the effects of noise on the job and off. in the 65 to 75 dB(A) range. If lifestyles include significant outdoor or open window HPDs come in various shapes, sizes, and PROTECTION conditions, these exposures over time can protection levels. While there is an HPD to suit Environmental Health and Safety degrade hearing. The U.S. EPA and various nearly every person and situation, no single states have set noise standards to protect HPD is right for every job, every person, or people from these adverse health risks. The every noise environment. EPA has identified the level of 70 dB(A) for 24 hour exposure as the level necessaryto Although some expandable foam earplugs come protect the public from hearing loss and close, there is really no such thing as aone-size- other disruptive effects from noise, such as fits-all HPD. Each person must be individually sleep disturbance, stress-related problems, evaluated to determine the best match of HPD learning detriment, etc. (EPA, 1974). for their environment, noise exposure, anatomy, and hearing ability. Noise-induced hearing loss (NIHL) typically is centered at 3000, 4000, or 6000Hz. As noise damage progresses, damage starts affecting lower and higher frequencies. On an audiogram, the resulting configuration has a distinctive notch, sometimes referred to as a “noise notch.” As aging and other effects contribute to higher frequency loss (6–8 kHz on an audiogram), this notch may be obscured and entirely disappear. Many people are unaware of the presence of environmental sound at damaging levels, or of the level at which sound becomes harmful. Common sources of damaging There is no such thing as the “best” hearing noise levels include car stereos, children’s protector. Needs vary by individuals, noise toys, transportation, crowds, lawn and environment, on-the-job communicationneeds, maintenance equipment, power tools, gun interaction with other types of safety equipment use, and even hair dryers. Noise damage is and other variables. The “best”HPD is the one cumulative; all sources of damage must be that will be consistently and properly used, all day, considered to assess risk. If one is exposed every day. to loud sound (including music) at high levels or for extended durations (85 dB A or Keep in mind that the object is to obtain a greater), then hearing impairment will occur. good and comfortable seal against noise and INDIANA UNIVERSITY SOUTHEAST Sound levels increase with proximity; as the that any leak seriously compromises the 4201 Grant Line Rd. New Albany, IN 47150 source is brought closer to the ear, the sound protection offered by HPDs. Most (812) 941-2333 level increases. environments require 15 dB or less of real protection. FORMABLE INSERT PLUGS PRE-MOLDED PLUGS SEMI-INSERT/ CANAL CAPS Most popular varieties are These are typically molded from soft plastic which These consist of a lightweight band with soft made from expandable, slow- is preformed to fit the ear. Reach around the back rounded or conical pods or flexible tips that recovery foam. of the head and pull outward and upward on the seal at or near the entrance of the ear canal. ear while inserting these plugs until theyfeel like Before fitting earplugs they are sealing the ear. » The Good: they can be useful for or semi-insert HPDs, intermittent exposures, since they examine the ear canals to » The Good: Pre-molded plugs are are quick to put on and take off and determine whether any relativelyeasy to insert and are reusable. easy to hang around the neck when obvious indication of possible medical problems not in use. are present. Also check for excess cerumen (ear » The Bad: Although some of the newer wax) that might be pushed further into the canal versions are one-size products, many are » The Bad: They generallyprovide less by the insertion of an earplug (in a few instances sold in two or more sizes and must be protection than either plugs or muffs –complete blockage of the ear canal may have individuallysized for each ear. They can and aren’t usuallyrecommended for occurred) If these conditions exist, then earmuffs work loose while wearing and require continuous long-term use because of should be worn until the problem is corrected. resealing. discomfort. To use, slowly roll and compress plugs into a very CUSTOM MOLDED PLUGS EARMUFFS thin cylinder and insert well in the ear canal. Individual impressions are made of each ear canal Consist of rigid cups with soft plastic using a quick-curing material. For some products, cushions that fit around the pinna (outer ear) Fitting is easier if you reach around the head to the impressions themselves are coated and sealed and against the head. The muffs must fully pull the ear outward and upward during insertion. to become reusable earplugs: for others, the enclose and seal around the ears to properly impressions are sent to a lab to make a subsequent block noise. custom ear mold. » The Good: Earmuffs are easy to » The Good: some employees like the use and fit, and to put on and take individual attention of having their own off , and therefore generallyrequire earplugs molded and fit, and for some less training in use.They provide ears custom ear molds are especially consistent protection in most cases. comfortable. » The Bad: Safetyglasses, long hair, » The Bad: Custom plugs are expensive, and beards mayinterfere with a especiallywhen the employee/technician good seal, or the muffs themselves » The Good: Properlyinserted, foam plugs time is considered as a cost. Slight and mayinterfere with other safety offer among the best protection available normal changes in ear canal size may equipment like helmets and hoods. and yet are found to be verycomfortable require taking new impressions. In addition, they mayfeel hot or for most wearers. heavy with long periods of use. If gaps are present, earmuffs can » The Bad: Some manual dexterityis actuallyincrease the level of noise required to roll and insert the plugs, they reaching the eardrum. are subject to contamination in dirty environments and theyare generally treated as limited-use or “throw away” products. USE THESE FIELD TESTS TO THREE STEPS TO EFFECTIVE CHECK FIT HEARING PROTECTION 1. Selection: Offer a varietyof hearing THE TUG TEST protectors,including a minimum of The fitter can very gently tug back and two types of pre-molded earplugs;two forth on the handle of the plug. If there types of formable earplugs; semi-insert is resistance and if the employee feels a devices and earmuffs. Consider the sensation of gentle suction of the eardrum, noise level, work environment, and then the earplug has probably achieved a seal. wearer’s convenience, communication In contrast, if the plug pulls out easily, an needs and preexisting hearing loss. adequate seal was not achieved. 2. Fit the Individual: Check the fit in each ear to see if the device is a good match of THE HUM TEST the individuals anatomy. Comfort is the After the fitter has inserted just one earplug, key to user acceptance. ask the employee to hum or “say ahhh.” 3. Train,Train,Train: Don’t just tell the If one ear is properly sealed (creating the individual how to wear the HPDs— occlusion effect), then the sound of the user’s have the wearer demonstrate correct voice will seem louder in the sealed ear. If placement of the device. Stress the the employee does not get this sensation, importance of a good seal for adequate then the ear canal is probably not adequately noise reduction, show what a good fit sealed. Sealing both canals at the same time feels and sounds like, and reinforce the will cause the voice to be perceived equally in need to use HPDs at all times in noisey both ears, or in the center of the head. environments.Teach the wearer how to care for HPDs and recognize when they THE LOUDNESS TEST need to be replaced. While in a noisy environment with plugs inserted in both ears, cup both hands over the ears. If there is a perceptible difference in the noise level, the HPDs are probablynot properly fitted; the HPDs should be blocking enough noise so that putting hands over the ears should not result in a significant difference. Conversely, the perceived noise level should increase markedly as the user breaks the seal of each earplug or raises each cup of an earmuff when in noise. IUS ENVIRONMENTAL HEALTH AND SAFETY Room 129 Hausfeldt Building 812-941-2989 Special thanks to Eastern Washington University for providing the template.