Hearing ProtectionComments (0)
This article is from Issue 40 of Woodcraft Magazine.
Sound advice made loud and clear
By Matthew Teague
Hearing loss may not be the most dramatic or painful shop-related injury, but it may be the sneakiest. That’s because unlike a sudden encounter with a blade or bit, hearing damage is both gradual and cumulative. Exposure to any noise over 85 decibels (dB) destroys nerve cells deep in the cochlea of the inner ear. Woodworkers claiming that they’ve “grown used” to the sound of a tool are already experiencing some hearing loss. In time, they’ll notice the loss outside of the shop, but by then it will be too late to do anything about it.
Fortunately, protection is cheap and easy. Here’s a selection of plugs, bands, and muffs that can save you from becoming a statistic. Choosing hearing protection involves considering comfort, convenience, and cost. The “best” is the one that gets used.
Note that hearing protectors are frequently ranked by Noise Reduction Rating (NRR), a measurement in decibels of how well a device reduces noise. In theory, exposure is equal to the noise level minus the NRR of the hearing protectors in use, but experts point out the numbers are based on ideal testing conditions. Most conventional hearing protectors, when properly sized and fitted, and consistently worn, can fulfill that requirement.
Hocks Noise Braker® Standards www.noisebrakers.com $14.99
Inexpensive and effective, disposable foam plugs are a woodworker’s first line of defense. Disposables are good to have on hand for visitors, when you’ve misplaced your go-to set, and for use under muffs for extra noise control. Some find plugs difficult to install. The trick is to roll them between your fingers to compress the foam, set them into the outer ear canal (it helps to raise the upper lobe using your free hand), and then let the foam slowly regain its shape.
Made of soft plastic or silicone, reusable plugs are easier to remove and reinsert than disposables, and can be cleaned for daily use. Like disposable plugs, they are convenient when wearing safety glasses or goggles.
While the less expensive plugs simply block out sound; newer pricier plugs, such as the Noise Breakers, provide variable levels of protection, reducing all noise to safer levels. Allowing normal conversation and music, variable protection encourages users to wear the plugs more often.
Reusable plugs and bands
Hearing bands are essentially caps, attached to a spring-action strip, that block the passage of airwaves into the ear canal. A good middle-ground protector, bands are easier to put on and take off (and to find on a crowded bench), than plugs, but are lighter and more comfortable than muffs. Like the pricier plugs, better bands provide smarter sound control. Zem’s acoustic band dampens and cancels certain frequencies, controlling loud noises and allowing users to hear normal conversations.
Ear-covering muffs are a good choice if you take hearing protection on and off frequently throughout the course of the day. Fitting over the ear makes them practical for multiple users, and size alone makes them easier to spot when hearing protection is needed. On the downside, muffs can be hot and heavy, and they don’t work with most full face masks. Safety glasses may break the seal of the muff against your head and reduce the amount of protection.
Most muffs simply block noise passively, but high-end muffs employ mechanical or electronic baffles that let in safe levels of noise but shut out noise above 85 dB. To encourage users to wear them even when they’re not needed, a few are available with microphones (which help with conversation), AM/FM receivers, and jacks for MP3 players.
Which Tools Cause Hearing Damage?
Woodworkers know they need hearing protection when using a router or planer, but many don’t realize that long-term exposure to “quieter” machinery can be just as damaging. For example, a half-hour in front of the tablesaw can be as harmful as 15 minutes with a handheld router. For every 3dB increase above 85dB, permissable exposure levels drop by half.
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