88, страница 48
getting the best
One of the keys to healthy hearing is to reduce tool noise to a safe level.
Every woodworker is aware of the danger of a spinning saw blade. But the potential harm from shop noise isn't always quite so obvious. These sounds can damage your hearing bit by bit over time. In fact, you may not even know it until it's too late.
Harmful Range. The problem is the loudness of sound, which is measured in decibels (dB). Most experts agree that exposure to noise of more than 85 decibels can be harmful to your hearing. And
dB LEVEL 60 70 80 90 100 110 120 130
Levels Above 85 dB Harmful to Hearing
the longer the exposure, the more damage that's done.
As shown in the chart below, most power tools operate at or above this harmful level. That's why it's always important to wear hearing protection when using these tools.
TYPES OF PROTECTION
You'll find most hearing protectors decrease the amount of sound that reach the ear drum an average of 25 decibels. This brings the noise made by most power tools down to a level that's safe, as the chart at left shows.
Ear Plugs. The most generic device is a set of ear plugs like the ones shown at the top of the opposite page. They're inexpensive and easy to use.
These small plugs fit in the ear and block the entire ear canal. Since they come in a variety of shapes and sizes, be sure to try out a few types until you find one that's comfortable enough to use all the time.
The most basic of these is the disposable foam plug. You simply roll the foam between your fingers and then place it in the ear canal and let the foam expand. I find it's often challenging to get them squeezed down small enough to get into my ear. And if they don't fit in the ear canal snugly they may not block the sound adequately or they simply fall out. Plus, you'll find you can only use these a few times before they need to be replaced.
A variation of the foam ear plug has a small foam tip attached to a plastic stem. You'll find these easier to insert into your ear. And the small foam tips don't create as much pressure in the ear canal. Both plugs are often connected to a plastic cord that hangs around your neck. This makes it easier to take them out of your ears without losing them.
Another type uses a soft plastic plug to block the ear canal. It has flanges at the tapered tip that allow them to adjust to fit the size of your ear. I sometimes find it hard to get these in my ear. But once in place, they're a lot more comfortable to wear for long periods of time.
ZEM Protector. If you find having something stuffed in your ear to be uncomfortable, there's another
ShopNotes No. 88