Popular Woodworking 2004-04 № 140, страница 69

claimer that the rating of a device does not guarantee its effectiveness. Why? Because the manufacturers don't know if you're using the device correctly.

Also, hearing protection devices are tested and rated under laboratory conditions where participants are monitored and educated and, in some cases, another person inserts and positions the devices. Muffs are easier to position properly than plugs.

If you know that the noise level of your planer while in use is 99dBA and you choose a pair of muffs that have an NRR of 20dB (which is about 10dB of effective protection), then the noise level at your ear when you are working with your planer will be about 89dBA. With these con

ditions and muffs, you can afford to work for about four hours and be adequately protected.

Oh, and wearing two hearing devices (such as muffs over plugs) simultaneously doesn't double your protection. It will increase the protection, but the increase is likely adding about 3dB to the effective protection of the plugs.

Not Just in the Shop

Hearing safety isn't only necessary in the woodshop. Yard and garden tools (lawnmowers, weed whackers, leaf blowers, edgers, trimmers, snow blowers and more) also can significantly contribute to damaged hearing.

A good rule of thumb for when you should be wearing hearing protection is if you have to speak

GETTING A CUSTOM EARPLUG MADE

louder to be heard. That's in a shop with equipment running, not a quiet room. The ambient noise level where you need to raise your voice to be heard three feet away is around 85 dBA.

So when you operate a tool or device where you need to raise your voice to talk to a person at arm's length you should be looking around for your hearing protection device.

The Bottom Line

I've given you a lot of information in this article about many different hearing protection devices. You now have two questions to ask yourself: Which type of hearing protection device is

best for your needs ? And are you willing to take the steps to protect your hearing?

I hope the information here has given you a clear look as to what hearing protection is best for you, but you'll have to decide if protecting your hearing is worth the extra effort. It's my hope that you'll decide it is, because otherwise you won't be able to hear the praise your next woodworking project will receive. PW

To fit a custom earplug, the first thing you need to know should be pretty obvious - don't try this yourself. Talk to a certified audiologist or other hearing expert. These custom devices can be made in many different colors and with or without cords or removal handles.

The first thing they will do is insert a foam

plug into the ear canal to protect the eardrum (seen in the photo at left). This plug has a long string attached to it that will help with removal.

Next, silicone material is inserted into the ear canal, conforming to the shape of the wearer's canal (seen in the middle photo). This process is similar to when you have teeth

impressions made at your dentist's office.

The resulting impression (in the photo at right) either goes to a manufacturer to make the plug or, in some cases, it is modified directly and the plugs will fit precisely into your ear canal, affording you an individualized, comfortable hearing protection device. - CE

First, a foam plug is inserted into the ear canal Silicone material is then injected into the ear canal Once the material dries, you have an impression of the

to protect the eardrum. to make the impression. ear canal that will be sent to a manufacturer.

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