3M 340-3002, P1400, P1401, H10A, H6F/V User Manual

...

The Sound Around Us

Noise is everywhere. It is the most pervasive environmental pollutant on the

planet. Virtually everything we do makes noise, and the more we do it, the faster

we do it, and the more of us there are - the more noise is made. In fact, silence, by

which we mean complete absolute quiet, is so rare that few of us have had the joy,

or perhaps even the possibility to experience it. If we have, it is so unusual that we

can likely cite the time and place of its last occurrence. The opportunities to savor

such tranquility are rapidly vanishing.

Not only is noise present in our daily routines and recreational activities,

but upwards of 5 million Americans, possibly as many as 30 million, work in

hazardous noise on a daily basis. Estimates from the National Institutes of Health

suggest that hearing loss aficts 28 million Americans. About 1/3 of those cases

are at least partially attributable to noise. Later in this booklet we’ll tell you how

the ear works and how noise can affect it, so you will understand why you should

protect your ears from too much sound today in order for your hearing to serve

you tomorrow.

In a world as noisy as ours we frequently tune out. Moreover, our culture is so

visually dominant that often sight overwhelms the other senses such as audition

(the hearing of sounds), which is habitually relegated to second-class status. The

purpose of this pamphlet is to address these issues – to increase your appreciation

and awareness of the sounds around you and to provide some tools to help you

protect yourselves from loud, annoying and/or hazardous sound.

Measuring Noise

Noise hazard depends on the level (sometimes called intensity) of the noise, its duration, and how often the exposure occurs. The point above which regular exposure to sounds becomes hazardous is a level of about 85 decibels (abbreviated dB, or sometimes dBA which is the value that more closely corresponds to human hearing). Noise is measured using a sound

level meter.

You Don’t Get “Used to Noise”

Noise does not have to be uncomfortably loud, or even painful, to be damaging. You may think your ears are “used to the noise,” but what has probably happened is that your hearing has been temporarily dulled or that hearing loss has already begun.

A Rule of Thumb

When you feel the need to shout in order to be heard three feet away, the noise levels are probably 85 dBA or more and hearing protectors are recommended.

Using Your Ears to Assess Noise Risk

If, after the noise stops, you notice a ringing, buzzing, or whistling in your ears that wasn’t there before, this is a warning indicator. Called tinnitus, this is like a “sunburn” of the nerve cells of your inner ear, indicating that they have been irritated and overworked. Tinnitus is especially noticeable in a quiet place, such as when you are trying to go to sleep at night. If you don’t protect your ears from noise, tinnitus can become a permanent, constant annoyance in your life.

Apparent mufing or softening of sounds after noise exposure is a warning sign that your hearing is affected by a temporary threshold shift. Repeatedly exposing your ears without protection can cause the shift to worsen and become permanent, resulting in untreatable damage to your hearing ability.

Jet Takeoff

Basketball

Game

Crowd Noise

Large

Stamping

Press

Chain Saw

Drilling Concrete

Leaf Blower

Vacuum

Cleaner

Inside Mid-

Size Auto

(65 mph)

Conversation

Floor Fan

Quiet Library

Rice Krispies

Watch

Ticking

Quiet

Wilderness

(no wind)

Pain threshold

Dual protection may be needed

Short exposures can cause permanent hearing loss

Prolonged exposure causes moderate to severe loss. Wear hearing protectors with extra care

Prolonged exposure causes mild to moderate loss. Hearing protectors required

Prolonged exposure causes slight hearing loss. Hearing protectors recommended

Residential boundary-noise limit

Sleep disruption may begin

Threshold of Hearing

Hearing Protection

Earplug Fitting Tip

Press ﬁrmly cupped hands over your ears while listening to a steady noise. With properly ﬁtted

Hearing loss due to noise is almost entirely preventable by judicious use of hearing

protection. To nd what is best for you, try different devices from the wide variety

available today. Be sure to carefully read the instructions because hearing protectors

must t properly and be worn correctly to do the job. Hearing protector effectiveness

is specied by a Noise Reduction Rating (NRR), typically ranging from 15-35

decibels. In practice the protection that normally can be achieved is about 10-20

decibels. The more carefully you t and wear hearing protectors, the higher your

protection will be. Hearing protectors may feel uncomfortable at rst, but give yourself

a chance to get used to them, just as you do with a new pair of shoes or glasses.

Foam plugs, made from expandable slow-recovery

foam, provide the best combination of comfort

and protection for most users. They must be properly

prepared for insertion. One size ﬁts most. Once in the

ear, foam plugs expand to provide a snug and secure

custom ﬁt. The two most common complaints about

foam plugs (“not enough protection,” and “they don’t

stay in”) are almost always solved by greater practice

and care in insertion.

plugs the noise levels should be about the same whether or not the ears are covered.

How Much Protection

Don’t get hung up on the NRR, the government-mandated noise protection factor that appears

on all hearing protector packaging. The numbers are based on optimized laboratory tests that, in

practice, represent what only a few of the most-motivated best-trained users can achieve. Your

best bet is to use the NRR only as an indicator that a product was designed and tested for noise

reduction. Except for very loud noises such as gunﬁre where selection is more critical, most

hearing protectors provide sufﬁcient protection when worn properly and consistently. Foam

plugs or earmuffs, or a combination of the two generally provide the highest levels of protection.

Slowly roll and

compress foam

plugs into a very

thin crease-free

cylinder. While

compressed,

insert plug well

into the earcanal.

Fitting is easier if you

reach around the head

to pull the ear outward and

upward during insertion.

repeated several times. Discard

plugs if they noticeably change their ﬁrmness or

do not re-expand to their original size and shape.

Keep the plugs clean

and free from material

that can irritate the

earcanal. They may

be washed in mild

liquid detergent and

warm water. Squeeze

excess water from the

plugs and allow to fully

air dry. Washing may be

Premolded plugs are made from ﬂexible materials

that are preformed to ﬁt the ear. They are generally

available with a joining cord to prevent loss. Although

the version pictured at the left is a one-sized product,

many premolded plugs are sold in two or more sizes

and must be individually sized for each ear. If after

a period of regular wear you’ve been unable to get

used to your earplugs, try another size, type, or brand

of hearing protector.

Reach around the

back of your head

and pull outward

and upward on

the ear while

inserting the

plug until you

feel it sealing.

This may seem tight

at ﬁrst, especially if

you’ve never worn earplugs.

Carefully twist the plug to break the seal for a

slow, safe removal.

Premolded plugs will normally last several

months or more

depending upon

the type, and

environmental

factors. They should

be replaced if they

shrink or swell, harden

or soften, tear, crack, or

become permanently deformed.

Wash them in warm soapy water and rinse well.

When dry, store them in a carrying case.

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