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NEWS FOR IMMEDIATE RELEASE
Sperian Hearing Protection, LLC |
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Hearing Protection From Ultra High And Low Frequencies Described In New Sound Source™ Bulletin Smithfield, RI -- Can standard earplugs or earmuffs protect you from the deep rumble of a turbine or the piercing noise of an ultrasonic welder—sounds outside the tested range of those protectors? That subject is addressed in a new Sound Source™ Bulletin recently released by Sperian Hearing Protection. The Bulletin, Sound Source #12, is authored by noted audiologist Brad Witt, and is available for free on the company's website under Articles at http://www.howardleight.com/bestpractices/educate According to Witt, who is Audiology and Regulatory Affairs Manager for Sperian Hearing Protection, LLC, most industrial noise falls in the mid-range of human hearing: between 20 and 20,000 Hertz (Hz). However, he writes, "There are some specialized pieces of machinery that emit noise levels near the lower and upper limits of the audible range—the low-frequency rumbling of some turbines or mining equipment, for example, in the frequencies below 100 Hz, or the piercing high-frequency noise of an ultrasonic welder emitting 15,000 – 20,000 Hz." Standard hearing protectors, on the other hand, are typically tested from 125 to 8,000 Hz, as indicated on the packaging. Will they still provide protection? There are two parts to this answer, says Witt. First, the human ear offers some built-in protection. Human hearing is much less sensitive to low and high frequency sound. "A 100 dB sound at 100 Hz will sound much softer than a 100 dB sound at 1,000 Hz, because the ear's sensitivity in the low frequencies is about 20 dB lower," says Witt, and human adult sensitivity to high-frequency noise is so low that a high-frequency noise device has actually been marketed to break up groups of loitering teens by emitting shrill sounds that adults apparently cannot hear. Second, earplugs and earmuffs do continue to offer protection beyond their tested range. Says Witt, "In the extended high frequencies, nearly any well-fit earplug or earmuff will offer good protection—about 35 dB. But in the extended low-frequency range, hearing protectors have a harder job to block incoming sound, offering 10-25 dB of protection in the lowest audible frequencies." When combined with the ear's lower sensitivity, however, that low frequency protection should still be adequate. A more common complaint, says Witt, is the "annoyance and discomfort, headaches and fatigue" caused by low frequency noise, the vibrations from which are "felt" more readily than heard. Sound Source is a periodic publication of Sperian Hearing Protection, addressing questions and topics relating to hearing conservation and hearing protection. Sound Source bulletins are offered as a public service and are freely available from the company's website under Articles at http://www.howardleight.com/bestpractices/educate Since its beginnings as a one-man operation more than 30 years ago, Howard Leight by Sperian has grown into one of the largest global manufacturers of hearing protectors in the industrial market and the recognized innovator in protection and people-oriented fit. Howard Leight offers the widest variety of hearing protection devices and technology, ranging from the highest attenuating Max® single-use earplug, to SmartFit® earplugs with Conforming Material Technology(TM) -- which delivers a more personalized fit -- to VeriPRO(TM), the new industry-changing fit verification system for hearing protectors. Utilizing Bilsom® Technology, Howard Leight earmuffs raise the bar on innovative design, performance and comfort, with features like padded wire headbands, high-visibility designs, unique sound management technologies and multi-level attenuation options. Visit Howard Leight online at http://www.howardleight.com With nearly 6000 employees worldwide, Sperian Protection is resolutely geared towards international markets. The world leader in personal protective equipment (hearing, eye, respiratory and fall protection, gloves, clothing and footwear), the Group offers innovative products adapted to high-risk environments so that all workers in the manufacturing and services industries can work with confidence. Sperian Protection is listed on Euronext's Eurolist and on the SBF120. For additional information, contact: ref: SPR8126.0407 |
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