Home | FAQ | News | Products | Shooting Sports | Resources | Get Info | Links | Search | Contents | Articles | Contact Us | Testimonials | Distributor Resources | Photo Gallery | Translation | Privacy | Downloads

FAQ – Frequently Asked Questions

FAQ - Hearing Protection and Noise

FAQ - Eye Protection

FAQ - Face Protection

FAQ - Chainsaw Leg Protection

FAQ Hearing Protection

1. What type of hearing protector do I need for my work environment or hobby?
2. What are some typical noise levels of sounds and noises in our environment?

3. How does exposure time affect my hearing protector requirements?

4. What exposure limits are established for impact noise (such as gun fire)?

5. How do I select a hearing protector with adequate attenuation for my noise situation?

6. What are the advantages of earmuffs over earplugs and vice versa?

7. What is the effect of dual protection? (Use of both earmuffs and earplugs).

8. How is the attenuation for hearing protectors measured?

9. What does the NRR (noise reduction rating) mean?

10. What factors, other than the noise level, combine to create a hearing damage?

11. Can I still hear the machinery and warning signals, when I use a hearing protector?

12. Can electronic hearing protectors help improve the ability to hear and communicate in noisy environments?

13. Is it safe to listen to FM Radio earmuffs when you work?

14. Who pays for my hearing protection at work?

15. How do I know if I have a hearing damage?

16. What can I do if I already have an existing hearing damage?

What type of hearing protector do I need for my work environment or hobby?

You have to consider the following factors, the noise level, the exposure time, and the comfort and ease of use of the protective device. First, you have to select a hearing protector that has adequate attenuation for your work environment. Second, you have to consider how you are going to use the protector. You may for instance choose a different protector if your use is intermittent, requiring you to take on and off the protector frequently, than if you are going to work a continuous eight hour shift in a noisy environment. An earmuff may be preferable in the intermittent environment, while an earplug may be the choice in a long-term exposure. An earmuff may be preferred in a cold environment, while an earplug may be the choice in a hot and humid environment. However, there is no right or wrong choice, as long as you chose a hearing protector with adequate protection, and you use it correctly for the entire exposure time.  

What are some typical noise levels of sounds and noises in our environment?

Below is a list of noise levels for sounds and equipment that you may be familiar with. Many of the examples are from the NIOSH website, but other references have also been used. It is important to keep in mind that you should really be concerned with the noise level at the ear, instead of the noise that is actually produced by the equipment. Therefore many of the examples have to be used with thought. For instance few consumers will be close to a jet engine or a fire engine siren, and their exposure is potentially more irritating than damaging. On the other hand, airport and fire engine personnel may indeed be exposed to the sound levels in the table below.

How does exposure time affect my hearing protector requirements?

 The hearing damage criteria established by the OSHA noise regulation takes into consideration the noise level and the exposure time. An exposure to 90 dB for eight hours is considered to be safe by OSHA, but it is recommended that you always use hearing protection when exposed to 100dB or more, even if the exposure is short. The exposure is doubled for every increase of 5 dB, as defined by OSHA. (Physically the sound pressure level doubles every 3 dB). The table below will explain the relationship between noise level and exposure time.  

Read more about this issue, "Facts about Permissible Noise Exposure".

Read a summary of OSHA's Hearing Conservation Regulation!

What exposure limits are established for impact noise (such as gun fire)?

U.S. Military Standard 1474D, Requirement 4 deals with impact noise and establishes risk criteria in the way of maximum number of exposures to impact sounds at different sound levels, as well as pulse length (the duration of the impact sound, measured in  milliseconds). The table below is a simplification of the military requirements, that does not take into consideration the pulse length. The table is therefore more conservative than the Military Standard.

How do I select a hearing protector with adequate attenuation for my noise situation?

You need to know the approximate noise level of the environment you are seeking protection against. The decibel (dB) level can be measured with a sound level meter. This works fine in professional environments, but homeowners and consumers can use estimates and common sense. Most equipment and machinery used by homeowners, such as lawn mowers, chain saws, line trimmers and similar devices do not produce sounds in excess of 100dB. In addition the exposure time is usually limited to a couple of hours.

If you use a tool that produces 100 dB, and plan to use it for an hour or two, and you use an average hearing protector with a 25 dB Noise Reduction Rating, you will be more than adequately protected. Of course, if you also are exposed to noise at work, you must take this into consideration, since it is your total daily dose that matters. To calculate your exposure the EPA noise regulation advises that you deduct the NRR from the noise level.

• Example, the tool and hearing protector discussed above: 100 dB - 25dB = 75 dB at the ear.
• For professional applications, when the noise level is known in dB(A), OSHA advises that the NRR be reduced by 7 dB:
• Example: 100dB(A) - (25 - 7)dB = 82dB at the ear.
• OSHA may also require a 50% reduction of the NRR after the above reduction:
• Example: 100dB - (25 - 7) x 0.5 = 91dB at the ear.

Read more about conflicting information from EPA, OSHA and NIOSH on how to use the Noise Reduction Rating.

What are the advantages of earmuffs over earplugs and vice versa?

Earmuffs are easier to use correctly, and therefore provide attenuation that is much closer to the laboratory derived NRR. Earplugs are hard or sometimes very hard to insert correctly, and therefore often do not provide the same attenuation in the field, as they do in the laboratory. This is the reason that NIOSH recommends different de-ratings for earplugs and earmuffs. You can read more about this subject by clicking on this link.

An earmuff may be preferable in the intermittent environment, while an earplug may be the choice in a long-term exposure. An earmuff may be preferred in a cold environment, while an earplug may be the choice in a hot and humid environment.

Most importantly, you should chose a protector that is comfortable and you should use it during the entire noise exposure.

What is the effect of dual protection? (Use of both earmuffs and earplugs).

This is a commonly asked question, and the answer is somewhat surprising. If you use an earmuff with 29 dB NRR and an earplug with 29 dB NRR, the estimated protection is 32 dB. The physical energy of noise doubles with every three decibels. This is a physical fact. So if you place two machines producing 90 dB of noise, next to each others, you will end up with a noise level of 93 dB. In the same manner if you double up protection you will gain 3 dB.

The above is an estimation, and both protectors have to be used correctly to achieve this result. We have actually seen laboratory reports indicating that as much as 6 dB can be gained from combined hearing protection. However, in real life situations, it is probably safe to assume 3 dB.

How is the attenuation for hearing protectors measured?

In order to establish the effectiveness of a hearing protector, the following method (with certain modifications) is used by all current standards. Ten subjects are exposed to sounds at 9 different frequencies (tones) and the lowest sound level that can be heard is established. The subjects are tested three times for each frequency, resulting in 27 individual sets of data. Thereafter each subject uses a hearing protector, and the procedure is repeated. The difference between the hearing threshold with and without hearing protector is the attenuation (noise reduction) achieved by a particular hearing protector. The average for all subjects become the mean attenuation, and the variance establishes the standard deviation. The example below shows the data compiled into a chart.

What does the NRR (Noise Reduction Rating) mean?

You can read an article about the NRR and other simplified methods at the following link.

www.elvex.com/facts03.htm

What factors, other than the noise level, combine to create a hearing damage?

Hearing damage can be created for many different reasons and sources. Industrial noise is certainly the most common and serious cause of hearing damage. Many leisure time activities also contribute, such as target shooting and hunting, noisy hobbies such as woodworking, as well playing in an orchestra or simply listening to music at excessive noise levels.

Another factor that contributes is heredity, and a certain level of hearing damage simply occurs from aging. Certain medications have also been demonstrated to contribute to hearing damage. As discussed above, exposure time is a major factor in determining the total daily noise dose.

Can I still hear the machinery and warning signals, when I use a hearing protector?

Extensive studies show that individuals with normal hearing, will hear warning signals slightly better when using a hearing protector. Individuals with an existing hearing damage will not hear the warning signals as well while using a hearing protector.

Can electronic hearing protectors help improve the ability to hear and communicate in a noisy environment?

Most likely you have heard about active headsets and noise canceling earmuffs. In theory the noise cancellation technology works by creating a negative sound wave for every noise (a series of sound waves), and thereby successfully cancel all noise for a perfectly quiet environment. Unfortunately this scenario is much more wishful thinking than reality. In order to be able to make the computations instantly, as we walk around in a changing noise environment, we would need a computer on a cart.

Today’s active or electronic headsets therefore are compromises that either are designed for specific noise environments, such as an airplane cockpit, or use some sort of filtering technique. The latter technique seeks to eliminate much more of the noise environment than of the speech, in order to improve the speech to noise relationship.

Electronic earmuffs can successfully eliminate impact noise, such as gunfire, and significantly contribute towards the ability to hear and communicate while on the shooting range or on a hunting team. This is done with an impact filter, which simply closes the electronics after sensing the sound wave from the noise impact. The filter reacts in microseconds and opens the electronics again after milliseconds (when the sound peak has passes).

Read about Elvex new DeTune electronic hearing protector.

Is it safe to listen to FM Radio earmuffs when you work?

OSHA has issued a letter of principal acceptance of this type of protection, on the condition that the noise level produced by the FM radio does not exceed 85 dB. Read the OSHA letter.

Who pays for my hearing protection at work?

OSHA has ruled that the employer pays for all necessary hearing protectors, including replacements. The employer decides what types of hearing protectors to offer, and has to make sure that they are adequate for the noise environment. The employer is required to offer a reasonable choice in order to maximize compliance. Read the OSHA Regulation....

How do I know if I have a hearing damage?

Your hearing threshold can be measured by an audiologist, and the instrument used to measure the hearing is called an audiometer. If you work in a noisy environment, and work for a larger company you have most likely already had your hearing tested.

What can I do if I already have an existing hearing damage?

Hearing damage is irreversible! If you already have a hearing damage, it becomes even more important that you make every effort to preserve your remaining hearing level. This means that you should avoid noisy environments whenever possible, and when you cannot avoid them, use an effective and comfortable hearing protector 100% of the exposure time.

If your hearing is already severely damaged, you should consult with an audiologist or specialist, in order to determine if a hearing aid may be able to improve your situation.

Return to top of page!

FAQ Eye Protection

1. How strong are today’s safety glass lenses?
2. What is a ballistic Vo rated safety glass?
3. My safety glasses scratch easily. Do you have any solution?
4. Do you offer safety glasses with anti-fog lenses?
5. Do you have smaller sizes of safety glasses for women and children?
6. Do you have safety glasses that can be adjusted for best possible fit?
7. What is the purpose of the different color lenses?
8. How do I select an appropriate eye protector?
9. How do I get my workers to wear their safety glasses?
10. Does OSHA approve safety glasses?
11. How are safety glasses tested, and to what standards?
12. How common are eye injuries?

How strong are today’s safety glass lenses?

Most safety glass lenses are today made from Polycarbonate, and this is a very tough material. The impact resistance of a Polycarbonate lens is approximately ten times higher that of a safety glass lens made from hardened glass. Both these lens types (has the potential to) meet the requirements of the Eye and Face Protection Standard, ANSI Z87. If you want to see an example of how tough a Polycarbonate lens is, click on this link: www.elevx.com/how-strong-is-polycarbonate.htm

What is a ballistic Vo rated safety glass?

Ballistic Vo rated is a test performed on a safety glass model to US Military standard MIL PRF-31013, clause 3.5.1.1, where the ballistic resistance of the spectacles shall be such that they will pass a Vo impact resistance test using a 0.15 caliber, 5.8 grain, T37 shaped projectile at a velocity of 640 to 660 feet per second. Note - this impact velocity requirement is 4 times the ANSI Z87 standard requirement of 150 feet per second 

My safety glasses scratch easily. Do you have a solution?

Polycarbonate gains its strength from being flexible instead of rigid. Because of this Polycarbonate lenses are prone to scratching, and are therefore usually protected by a hard coating. Even with a hard coating Polycarbonate has to be handled carefully, and should cleaned with soap and water and dried with paper tissue. If your work environment is dusty and abrasive, you may want to consider safety glasses with hardened glass lenses, since they offer better scratch resistance than Polycarbonate lenses. Safety glasses with glass lenses are usually more expensive, and are not available in contemporary fashion styles. Elvex does not offer safety glasses with hardened glass lenses.

Do you offer safety glasses with anti-fog lenses?

Yes, Elvex offers different solutions to avoid fogging of safety glasses. Certain designs that provide a space between the face and the lens allow for air circulation and help minimize fogging problems. Examples: UniWraps, SG-20, Challenger, SG-25, Summit II, SG-29, Orbit, SG-36

We also offer several models with anti-fog coated lenses. The product number includes an AF designation after the regular product number. Examples: TNT (SG-13C-AF), Xenon, SG-14, TTS (SG-15C-AF), Trix (SG-17C-AF), UniWraps (SG-20C-AF), Challenger (SG-25C-AF), Summit II (SG-29C-AF), Sphere X (SG-32C-AF) and (SG-32G-AF).

Click this link to go to our main safety glass page: Elvex main Safety Glass page.

Do you have smaller sizes of safety glasses for women and children?

Yes, we offer a couple of styles that are smaller or have a more aggressively curved lens. Elvex TTS, SG-15-small, Challenger Small, SG-23, fit small featured adults as well as many children. Also our models TNT SG-13,  Xenon, SG-14, Trix, SG-17, Elite, SG-200 and Summit II, SG-29, offers a good fit for women and small featured adults. Click on the links below.

TTS, SG-15, Challenger S-SG-23, TNT- SG-13, Xenon- SG-14, Trix- SG-17, Elite- SG-200, Summit II- SG-29,

Do you have safety glasses that can be adjusted for best possible fit?

Several models in our product line offers both angle and length adjustment of the temples. The angle adjustment allows the lens to be tilted so that it offers the best possible protection for the job at hand. This feature is also helpful for individuals with asymmetric faces (it is common that the right and left ears are at different heights). Models with both length and angle adjustment: UniWraps, SG-20 , Challenger II, SG-26 (being discontinued), Bifocal Safety Glasses, RX-100.

Click this link to go to our main safety glass page: Elvex main Safety Glass page.

What is the purpose of the different color lenses?

Lenses are offered in different tints and coatings for a variety of reasons, such as vision enhancement, glare reduction and simply cosmetic appeal. Examples:

You can read about the light filtration properties of all Elvex lenses, by clicking on this link: Light Transmission for Elvex Safety Lenses

How do I select an appropriate eye protector?

ANSI Z87.1 provides guidelines for what type of eye protection to use for different types of hazards. Here is some basic information:

·        If you use a face shield, it is strictly a face protector, and required eye protection has to be selected as appropriate.

·        If your work environment has impact hazards, use safety glasses that are appropriate for this type of hazard. Polycarbonate lenses are suggested. Make sure that glasses provide adequate coverage, so that there are no gaps in critical areas.

·        For chemical splash or mist, use only goggles that seal tightly against the face. For this environment make sure that the goggles have only indirect ventilation or no ventilation. As appropriate chose anti-fog coated lenses.

·        For injurious rays, such as welding or laser light, specialized safety glasses must be worn. Welding lenses must be marked with a SHADE designation, normally in the range of 2 – 5. Choose level of protection appropriate for the equipment that you use. Laser lenses must be selected uniquely for each laser’s characteristics, such as wavelength and power. Laser lenses must be marked with both wavelength and Optical Density (the protection factor).

How do I get my workers to wear their safety glasses?

Compliance with requirements to wear safety glasses used to be a big problem in industry. However, safety glasses have become much more lightweight and stylish, to the point where workers actually want to wear their safety glasses. If you offer a selection of stylish safety glasses, that are appropriate for your work environment, you will find that compliance is no longer a big problem.

Does OSHA approve safety glasses?

No, OSHA does not approve safety glasses, or any other personal protective equipment for that matter. OSHA simply requires that manufacturers test their products to the appropriate ANSI standard. Read OSHA’s Eye and Face Protection Regulation, 29 CFR - 1910.133

How are safety glasses tested, and to what standards?

Safety glasses are required to be tested to ANSI Z87.1-2003. This standard includes optical requirements as well as physical requirement. Here is a list of the tests that are required:

How common are eye injuries?

Every day an estimated 1,000 eye injuries occur in American workplaces. The financial cost of these injuries is enormous--more than $300 million per year in lost production time, medical expenses, and workers compensation. No dollar figure can adequately reflect the personal toll these accidents take on the injured workers.

The Occupational Safety and Health Administration (OSHA) and the 25 states and territories operating their own job safety and health programs are determined to help reduce eye injuries. In concert with efforts by concerned voluntary groups, OSHA has begun a nationwide information campaign to improve workplace eye protection.

Take a moment to think about possible eye hazards at your workplace. A 1980 survey by the Labor Department's Bureau of Labor Statistics (BLS) of about 1,000 minor eye injuries reveals how and why many on-the-job accidents occur.

Read the full OSHA article at: http://www.pp.okstate.edu/ehs/training/oshaeye.htm

Return to top of page!

Home | FAQ | News | Products | Shooting Sports | Resources | Get Info | Links | Search | Contents | Articles | Contact Us | Testimonials | Distributor Resources | Photo Gallery | Translation | Privacy | Downloads

Copyright © 2002-2008,  Elvex Corporation