Personal Protection Equipment (PPE): Hearing Protection
Posted in Home Improvement on June 23, 2018
Wear hearing protection! A circular saw can be as loud and nerve-wracking as a jackhammer. Hearing lost is usually gone forever.
I hated it! Despised il! Avoided it! Cutting plywood with a circular saw was a chore l absolutely dreaded. But why? It wasn't the weight, size, smell or cost of the wood that tormented me. So, why?
I finally realized the tormenter was one I couldn't see: it was noise, that piercing howl at a whirling blade grinding through stubborn plywood.
Loud noise causes pain; a pain no less real, no less damaging, than whacking your thumb with a hammer or dropping a brick on your toe. Worse yet, hearing damage is permanent. Add in the evidence that noise causes high blood pressure, ulcers, and headaches — and you‘ve got a great case for wearing hearing protection.
What’s hearing protection gotta do with “Using Tools”? In my book, a tool is anything that helps a job go faster, safer or makes a task more enjoyable. Hearing protection does all three.
Ear Anatomy 101
The intricate workings of the ear — how sound waves are turned into electrical impulses the brain can understand — are a small miracle. The sound is channeled through the ear canal and eardrum, then on to the middle ear (remember the hammer, anvil, and stirrup from seventh-grade biology?) It's in the cochlea of the inner ear that most noise-related hearing damage occurs.
The cochlea is lined with small hairs that move nerve impulses along to the brain. These hairs can be bent, broken or literally blown away by loud noises. The hairs in the first bend of the cochlea — the high-frequency receptors — are the most susceptible to damage. Damage to these means soft sounds like S, SH, and F or higher pitched voices cannot be heard as easily (while deeper voices or stronger sounds may still be understood). These high-frequency receptors are also the first to go with age; many people begin to experience a natural hearing loss at around 50 years of age.
Tinnitus, a constant ringing of the ears, can be caused by long exposure to loud noise, or even by a single enormous impact noise. Woodworkers, musicians and factory workers are often plagued by tinnitus.
Remember, the damaged nerve cells of an ear will never heal. Hold onto what you've got. Use hearing protection.
Understanding and choosing protection
Do your ears a favor and take a minute to walk through some simple math.
|Noise Sensation||db Rating||Examples|
|Painfully loud||140 db||Gunshot from close range, jet engine|
|Painfully loud||130 db||Jackhammer|
|Extremely loud||120 db||Chain saw|
|Extremely loud||110 db||Circular saw, gas-powered mower|
|Very loud||100 db||Router, vacuum cleaner, manufacturing plant|
|Very loud||90 db||Drill press, truck traffic|
|Acceptable||80 db||Electric razor|
|Acceptable||60 db||Normal conversation|
Noise is measured in decibels (db): the louder the noise. the higher the db rating. Most experts peg 85 db as the safe maximum noise level. Hearing protection devices are rated in terms of their ability to block noise and lower decibel levels: this is their noise reduction rating (NRR). Hearing protection with an NRR of 30 will reduce the noise reaching your ears by around 30 db.
Tying all this together, if you're working with a circular saw screaming at 110 db, you need a hearing protector rated at 25 NRR or more to bring your ears into the sale range (110 db minus 25 db equals 85 db). Extremely loud situations. such as rifle ranges or jackhammering, dictate using ears muffs and earplugs combined.
Hearing protection comes in two basic types: in-the-ear (Photo 1 and outside-the-ear (Photo 2) varieties. In selecting a protector, pick one with an NRR that brings your hearing into the 85 db safe range. Also, make certain to pick one that’s comfortable and convenient enough so you'll actually wear it.
Foam earplugs are available in corded and non-corded styles. Inexpensive and difficult to clean, they are considered disposable. Flange-type earplugs are washable, reusable, and comfortable. Available corded or non-corded. Banded earplugs combine the protection of an in-ear device with the convenience of a hearing muff. Pads swivel for comfort.
They are inexpensive, yet otter extremely good protection. The best in-ear earplugs otter an NRR of 33. Their effectiveness lies in their ability to conform to the ear canal, blocking the sound paths. Foam types are twisted then inserted in the ear, when they expand to block the ear canal.
On the downside, flange (Photo 1) and foam plugs do such a good job blocking noise that they can make normal conversation difficult. And because they go inside the ear where they pick on wax and oils, they're more likely to attract dirt and sawdust when removed. They must be replaced or cleaned frequently. Also, some people simply don’t like putting things inside their ears.
Noise-activated earmuffs may be either battery operated or non-electronic. These muffs increase the amount of protection as noise levels rise, yet permit (or amplify) normal conversation. Wrap-around earmuffs with a strap that wraps around neck allow hard hats and helmets to be easily worn. Other versions have muffs that attach directly to headgear. Foam ear caps are ideal for those who don’t like using in-ear earplugs or larger muff-style hearing protection. Worn under the chin, they are lightweight and easy to use. Combination goggle-muffs combine hearing and sight protection into one easy-to-use unit.
They cost more, but last longer (and are harder to misplace). The best earmuff offers an NRR of around 30. They generally permit conversation more easily than earplugs. When not in use, they can be looped down around the neck or be perched atop the head, Mickey Mouse style. They also protect the tender outer ear from flying debris.
Bear in mind, cotton and tissue paper don't offer adequate protection (though damp tissue paper will work in a pinch). Radio headphones only add to the noise level.
When to wear hearing protection
Ideally. you should wear hearing protection any time the noise level exceeds 85 db (the approximate volume of a drill or garbage disposal).
Of course. wearing hearing protection isn't always practical, but be especially diligent around:
- Power tools. The high-pitched whine or a router or miter saw can be especially damaging. Even clean up afterward with a wet-dry vacuum can be painfully loud.
- Impact sounds. Hammering in a confined space can be torturous, even with a small hammer. The crack and screech of pry bars during demolition can be amazingly noisy, too.
- Outdoor equipment. Chainsaws, lawn mowers, and string trimmers all call tor hearing protection even if your neighbors think you look funny. Hard hats with integral face shield and earmuffs are available for chainsawing.
- Sporting and concert events. The noise from a gunshot is at the top of the decibel chart. Rock concerts can peak at 130 db.
At first, hearing protection may make you feel uncomfortable or out of touch with the sound or your tools. The whim and warning signs of your power tools will sound different but after a while, you'll relearn these sounds.
After trying both types, I've settled on muffs. The same pair has been my companion in the workshop and on the workshop for 10 years. In time, hearing protection becomes habit forming. I would no more cut a board without my muffs than drive my car without a seatbelt.
Use hearing protection even for short work periods. Hearing loss is cumulative; lots of short working spurts without hearing protection can add up to hearing loss.
Also, remember to keep an extra set or hearing protection around for visitors or helpers. It's a good idea to teach your kids to use them. too.
Prevention as a cure
There are other steps you can take to preserve your hearing.
- Make sure the tools or machines you are using are well oiled and balanced.
- Mount machines on carpet pad or rubber washers to reduce vibration and noise.
- “Soften” the work area by lining it with sound-absorbing materials such as cork, heavy drapes or fiberboard panels that absorb and block noise; install an acoustical tile ceiling and some old indoor/outdoor carpeting.
- Use sharp blades and bits, they'll cut faster and quieter.