Popular Woodworking 2004-04 № 140, страница 68
can still hear a person talking to you from three feet away. Using stereo earpieces (whether they are plug or muff design) as hearing protection won't work. These devices are not rated or evaluated for hearing protection. Lots of Plugs Plugs can be found in many shapes, materials and colors. They are either one-size-fits-all or they can be custom-made. Plugs that are one-size-fits-all usually are made out of a foam or soft plastic material. The foam materials usually are designed for a single use or for a few insertions (if the plug remains dirt-free). Those made of a soft plastic material are designed for multiple uses and can be cleaned with soap and water. Plugs can be shaped as cones, \ ONLINE INFORMATION ON HEARING SAFETY AND HEARING LOSS American Academy of Audiology - audiology.org American Speech-Language-Hearing Association - asha.org American Tinnitus Association - ata.org Better Hearing Institute - betterhearing.org League for the Hard of Hearing - lhh.org National Hearing Conservation Association - hearingconservation.org National Institute of Occupational Safety and Health - T mushroom caps, cylinders or bullets. They are designed to fit almost completely into the ear canal (with only a small bit of the plug showing, see "Proper Fit for a Foam Plug" at right) or they are designed to seal only the ear canal opening. It's extremely important to review the insertion instructions from the manufacturer prior to use. Plugs are only as good as the seal they create for your ear. If you try a particular type and find that it doesn't fit well, try another. Plugs with a handle or those on a retention band are appropriate for use with short duration noises or when your hands are dirty. Be sure to clean your hands before touching the end of the plug that goes into your ear canal. Everything on the plug will come in contact with your skin, and some products in your shop shouldn't ever come in contact with skin. Custom-made plugs are crafted from an ear-mold impression that can jj be taken by a licensed audiol- > ogist or a certified hearing aid dispenser (check out the story "Getting a Custom Earplug Made" on page 67 for more information). What it Sounds Like Here's an easy way to determine if your hearing protection device is on properly. Take your index finger and push on the skin just before the right ear canal opening to close it completely. Then say a few words out loud. Your voice should sound a bit louder in your left ear. Next, while keeping your right ear plugged, plug your left ear canal opening in the same manner. Repeat the same words and your voice should now sound like it is near the center of your head PROPER FIT FOR A FOAM PLUG When you're using a foam plug (which are the most common types of earplugs on the market because of their cost and dispos-ability), you need to be sure you know the proper way to install it. An improperly fitted foam plug won't do you any good - and it could even do some harm. As you can see from the photos, there is a wrong way to install the plug (top), and a right way (bottom). You might think that the correct version is pushed into the ear too far, but you're wrong. There's a lot of space in there, and you want to make sure you seal the ear canal opening. It's very important that you read the insertion instructions from the manufacturer before using any of these products. - CE or in the front of your throat. When you position a plug or put a set of muffs on correctly, you should experience the same effect. If your voice sounds louder in one ear after you have positioned the hearing protection device, reposition the protector on the side that sounds the loudest. When you are wearing hearing protection, it's normal for you to hear your own voice louder than you hear other people's voices. If you are working around others in your shop, you will need to raise your voice slightly to be heard by others around you (especially if they are also wearing hearing protection). Even if you are wearing a hearing protection device, you should still be able to hear warning signals (such as a smoke alarm). The hearing protector will reduce the overall amount of noise but will not eliminate it completely. This is also true of active hearing pro- tection devices that react to noise when it reaches a particular level established by the manufacturer. Which Device Should I Use? While each type of hearing protection device has a different level of effectiveness, the best protection is figuring out which one you will actually use. Wearing hearing protection should be as automatic as wearing eye protection or proper shoes when you operate power tools. Hearing protection devices are rated with a number value for their effectiveness in reducing noise called the Noise Reduction Rating (NRR). I have provided images of some typical types of hearing protection and included their effective noise-reduction ranges (see "Muffs and Plugs: Pros & Cons" on page 65). The NRR was implemented by the Environmental Protection Agency. The EPA includes a dis- 66 Popular Woodworking April 2004 |
