HHearing Protection CanHearing Protection CanSSSave Hearing

ThThThere's More than Meetsthtthe Eye — or the Ear!

Double Hearing Protection (earmuffs over ear-plugs) may be used in very noisy areas for daily aver-age exposures greater than about 105 dB(A). Therule of thumb is that properly fit double protectionadds about 5 dB to the protection rating of thehigher rated HPD. Using plugs with a nominal pro-tection of 20dB and muffs with a protection of 20 dBdoes NOT give 40 dB, but something closer to 25 dB.

Hearing aids are NOT hearing protectors.Most hearing aids are vented, making them useless ashearing protectors whether they are turned on oroff. Do not use hearing aids in high noise areas; theycan significantly aggravate noise exposure conditions.

Electronic HPDs come in two basic varieties. Thecommunication/limiter h of earmuffswith electronics built in to tside soundsor radio communication ally limit thelevel on the inside of the safe value.This can be used for high le, like forklift drivers, who frequently of noisy areas.

Active HPDs use sound lifiers, andspeakers to generate "an ncellationwave patterns to reduce e the earcup.The active technology, av r an open-back-headset (like a Walkmearmuffs, is primarily effelow 500 Hz) noise and fosuch as when combined tion systems. The open-baless than 10 dB of attenuare intended primarily forthan protecting from noi

Hearing Protection Devices (HPDs) are one componentof an effective hearing conservation programs. HPDs canprotect the delicate hearing system from the effects ofnoise on the job and off.

HPDs come in various shapes, sizes, and protection levels.While there is an HPD to suit nearly every person andsituation, no single HPD is right for every job, everyperson, or every noise environment.

HPDs must be selected and properly fitted based on thenoise environment where they will be used. Too littleprotection does no good; too much can interfere withcommunication and result in employees feeling isolatedfrom their surroundings.

This pamphlet is intended to show the various types ofHPDs available and give some guidelines where eachmight be appropriate. NHCA endorses no specificmanufacturer or distributor of HPDs.

Permission is granted for individuals to print and copy this document.However, the document cannot be used commercially without permissionfrom the NHCA office.

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ctive for low-frequency (be-r specialized applications,with electronic communica-ck versions, which provideation at and above 1000 Hz, reducing annoyance ratherse hazard.

For more information, contact:Med Compass7841 Wayzata Boulevard #214Minneapolis, MN 55426800-205-8729 (V), 952-542-0095(F)sales@medcompass.net (E-mail)www.medcompass.net

Printed on recycled paper

NHCA thanks Elliott H. Berger for his comments and editorialcontributions to this project. 2.96

There's no such thing as the "best" hearing protector.Needs vary by individuals, noise environment, on-the-jobcommunication needs, interaction with other types ofsafety equipment, and other variables. The "best" HPD isthe one that will be consistently and properly used, all day,every day. Keep in mind that the object is to obtain agood and comfortable seal against noise and that any leak

seriouslycompromisesthe protectionoffered by HPDs.Most environ-ments require15dB or less ofreal protection.The followingare some HPDoptions:

Formable Insert PlugsMost popular varieties are made from expandable, slow-recovery foam. To use, slowly roll and compress plugsinto a very thin cylinder and insert well into the earcanal.Fitting is easier if you reach around the head to pull theear outward and upwardduring insertion (see figure).The Good: Properly in-serted, foam plugs offeramong the best protectionavailable and yet are found tobe very comfortable for mostwearers. The Bad: Somemanual dexterity is requiredto roll and insert the plugs,they are subject to contamination in dirty environments,and they are generally treated as limited-use or "throwaway" products.

Premolded PlugsThese are typically molded from soft plastic which ispreformed to fit the ear. Reach around the back of thehead and pull outward and upward on the ear whileinserting these plugs until they feel like they are sealingthe ear. The Good: Premolded plugs are relatively easyto insert and are reusable. The Bad: Although some ofthe newer versions are one-sized products, many aresold in two or more sizes and must be individually sizedfor each ear. They can work loose while wearing andrequire resealing.

Custom Molded PlugsIndividual impressions are made of each earcanal using aquick-curing material. For some products, the impressionsthemselves are coated and sealed to become reusableearplugs; for others, the impressions are sent to a lab tomake a subsequent custom earmold. The Good: Someemployees like theindividual attention ofhaving their ownearplugs molded andfit, and for some earscustom earmolds areespecially comfortable.The Bad: Customplugs are expensive,especially when the employee/technician time is consid-ered as a cost. Slight and normal changes in earcanal sizemay require taking new impressions.

Semi-Inserts/Canal CapsThese consist of a lightweight band with soft rounded orconical pods or flexible tips that seal at or near theentrance of the earcanal. The Good: They can be useful forintermittent exposures, since they are quick to put on and

take off and easy to hang around the neck when notin use. The Bad: They generally provide less protec-tion than either plugs or muffs and aren't usuallyrecommended for continuous long-term use becauseof discomfort.

EarmuffsConsist of rigid cups with soft plastic cushions thatfit around the pinna (outer ear) and against the head.The muffs must fully enclose and seal around theears to properly block noise. The Good: Earmuffsare easy to use and fit, and to put on and take off, andtherefore generally require less training in use. Theyprovide consistent protection in most cases. TheBad: Safety glasses, long hair, and beards mayinterfere with a good seal, or the muffs themselvesmay interfere with other safety equipment likehelmets and hoods. In addition, they may feel hot orheavy with long periods of use.

Play it by the Numbers-Noise Reduction EstimatesLabeled Noise Reduction Ratings (NRRs) are basedon optimized lab testing and bear little resemblanceto what groups of users get in practice. Use thepresence of such a rating not as a buying guide, butas an indicator that a device has been designed andtested for noise reduction. Labeled NRRs typicallyvary from 20-30 decibels; in practice the protectionthat can normally be achieved is about 10-20 decibelsor less, especially when poorly fitted. This modestdegree of protection may be sufficient for someindustrial environments as long as the devices areworn consistently, however, the highest values ofattenuation are achieved by wearing foam earplugs,earmuffs, or a combination of those two.

There's no such thing as the best...There's no such thing as the best...There's no such thing as the best...There's no such thing as the best...There's no such thing as the best...

The "best" HPDis the one that

will be consistentlyand properly used,all day, every day.