Healthy Woodworking

Shop safety includes a whole lot more than leaving the guard in place on your tablesaw. There's your eyes, ears, and lungs to think about. To protect these, select the right gear, then make a habit of using it.

All safety eyewear must be officially approved. That approval comes from the American National Standards Institute (ANSI), a voluntary organization that looks after the development of standards used in business, industry, government, and educational institutions. ANSI wrote the standard for safety eyewear for the industrial workplace, but your workshop differs only in size. The possible hazards to your eyes, such as flying chips of metal or wood, dust, or contact with harmful liquids, remain the same.

All quality protective eyewear, including face shields, complying with ANSI standard Z87.1 (of 1989) will have that letter and numbers stamped or molded into the frame or shield. Lenses (usually of hard polycarbonate) that comply will bear the manufacturer's initials (AO for American Optical, X for UVEX, etc.) somewhere out of the line of sight. Any manufactured protective eyewear you consider purchasing should bear both inscriptions.

What does the ANSI standard mean to you? For one thing, the frames and lenses work together for protection. Industrial safety glasses have lenses that withstand nearly four times the impact of regular impact-resistant lenses. Compliant frames have inner retention lips that keep unshattered lenses from being driven into your eyes under the force of heavy impact. They also meet the standards for pressure and impact that regular frames do not. And for complete protection, all industrial safety glasses should have side shields.

You'll find, though, some contemporary styles of one-piece, wraparound safety glasses that might not carry the ANSI Z87.1 imprint or the initials of the maker. They may meet or exceed the standard, but due to their one-piece construction, they don't comply with ANSI's lens-and-frame stipulations.

Depending on your eyesight, you have several options in safety eyewear. If you don't require corrective lenses (or wear contact lenses), you may select prefabricated safety glasses with clear lenses in place, safety frames in which safety lenses are inserted, or goggles. (There's also a combination eyeglass/goggle available.) If you have to wear corrective lenses while woodworking, you can don prefabricated safety glasses or goggles over your normal eyewear; use a flip-up face shield; or have prescription safety glasses made.

With safety glasses, always check (or ask) for ones with scratch-resistant lenses. And to prevent them from fogging when you're wearing a dust mask, have them treated with an antifog coating. Many companies offer permanent antifog coating on nonprescription safety glasses.

If there is one thing to remember from reading this, it's that hearing loss is cumulative and permanent. Hearing protection can't restore what you've already lost, but it can halt further deterioration. If you value your hearing, you'll want to wear ear protection for any noise over 85 decibels (dB), and for very loud noise, such as that made by a chainsaw, you'll need added protection, such as earplugs under earmuffs. (See the chart below for tool loudness ratings.) Permanent damage to your hearing ability can result from exposure to over 100 dB for two hours or even less.

Note: The decibel scale by which sound is measured happens to be logarithmic, not linear. As demonstrated in the chart, below, that means that a 100 dB noise is 10 times as loud as a 90 dBnoise. And 90 dB is 10 times as loud as 80 dB.

In industry, the federal Occupational Safety and Health Administration (OSHA) helps reduce noise at its source by doing site-specific studies and giving recommendations to manufacturers for quieting operations. You can do a similar thing in your home shop by purchasing low-noise power tools and equipment. WOOD® magazine's tool-comparison tests usually provide noise ratings when applicable.

Even with quieter tools, though, you'll still need hearing protection when noise exceeds dangerous exposure levels, such as when you're routing. So how much do you need? You first must understand how hearing protection is rated.

Manufacturers of hearing protectors assign each of their products a laboratory-based Noise Reduction Rating (NRR), and by law, it must be shown on the label of each hearing protector sold. The NRR supposedly equals the drop in decibels (attenuation) provided by the device. For example, an NRR of 20 would reduce a 100 dB noise to an audible 80 dB. In the real world of your shop, however, the actual NRR proves to be somewhat less. That's why you should select hearing protection with an NRR of at least 25.

According to a 1997 study by the National Institute of Occupational Safety and Health (NIOSH), laboratory data show that earmuffs provide the highest real-world noise attenuation values, followed by foam earplugs. However, other data from OSHA and industrial sources, such as 3M, find that properly fitted foam or flexible plastic earplugs offer the greatest protection—from an NRR rating of about 29 to 33. NIOSH, more generally speaking, states that "the best hearing protector is the one that the worker will wear."

Basically, you'll find three types of hearing protectors. Foam earplugs that mold to fit your ear canal offer the highest NRR and cost the least (about 1 cents a pair). Band plugs, similar to foam ones but made of flexible plastic and joined with a head/neck band, come next, and cost a bit more.

Researchers at 3M, which manufactures several styles of hearing protectors, have studied why hearing protection frequently fails in the industrial workplace. Some of their findings follow:

* Improper sizing and insertion. The wearer tends to fit plugs too loosely, even though they're available in various sizes. If fit too tightly, they are a discomfort and the wearer removes them. Also, a person can have different-size ear canals, so each must be sized separately.
* Incompatibility with other protective equipment. Earmuffs often don't seal properly over safety glasses. Long hair also interferes.
* Poor communication. Hearing protection tends to attenuate high pitches, typical of voices. Wearers loosen, alter, or remove protectors to hear others.
* Wear and tear. Seals wear down on muffs. Foam plugs become less flexible and unable to properly mold to the ear canal. Premolded plugs shrink. Ear wax and perspiration also build up on them. Earplugs should be checked frequently and pushed in. Even chewing gum can shift them out of position.

Finally, here's a test to see if earplugs fit properly: After inserting the plugs, cup your hands over your ears, then take them away. If you hear a difference, they're not being worn correctly. Remove them, refit, then try again. And don't forget to wash them in mild soap and water after a few wearings.

Exposure to wood dust in excess of five milligrams per cubic meter of air is hazardous to your health, says OSHA. It's even more so from western red cedar. Because that very common wood has been linked to respiratory problems, OSHA limits its dust to 2.5 milligrams per cubic meter.

How much is five milligrams? It's actually less than .0002 of an ounce. (A dime weighs .08 ounce!) So according to OSHA standards, a woodshop measuring 15×30' with a 10' ceiling would reach the exposure limit when there's .02 ounce of wood dust in the air. Granted, that's not much dust. But OSHA cares about it because exposure to wood dust has been associated with a variety of adverse health effects that include dermatitis, nonallergenic and mucosal respiratory effects, allergic respiratory ailments, as well as cancer. You and your home shop don't fall under OSHA's scrutiny, but for your own well-being, you'll want to do all that you can to cut down your exposure to dust.

The highest degree of dust control consists of a three-pronged approach. Of primary importance is the installation of a dust-collection system that captures it at the source. The second prong is an air-filtration system that pulls out airborne particles. And the third is the use of personal dust protection. Of course, most woodworkers typically start with the latter, then add the rest as their shop activity and hobby grow. So we'll look at dust masks as your first line of lung protection.

Protection for your respiratory system has two categories: nuisance protection masks and respirators.

For occasional light sanding that won't generate heavy dust, you can opt for the common paper throwaways with the single elastic band and the metal nose clip. The next step up is the woven cloth or polyester mask with two elastic bands and an exhaust port. Although they're still disposable, they're NIOSH approved. Costlier variations of these are washable for years of wear.

For prolonged exposure to fine dust, mist, and dangerous fumes you'll need an air-purifying respirator with changeable filters that remove specific, unhealthy contaminants from ambient air. These half masks, because they're made of rubber or silicone, are flexible to fit your facial contours. Several straps ensure a tight fit. And you'll have a choice of filters, depending on the kind of protection needed.

High-efficiency particulate air (HEPA) filters are 99.97% efficient in removing particles of 0.3 micrometer in diameter. A set of them may cost as much as the respirator itself. NIOSH (standard 42 CFR84) designates them as follows:

* N100, not resistant to oil particulates;
* R100, resistant to oil particulates;
* P100, oilproof.

Here's a tip concerning air-purifying respirators: Never simply store one on a shelf. Keep it in a sealed plastic bag; otherwise it will filter the ambient air and clog the filters while it just sits there.

To test the respirator, put it on and cover the air outlet with one hand. Then blow gently. Anywhere your other hand can feel air escaping around the mask is where it will leak when you inhale, so readjust for fit.