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Hearing Protection Questions

Discussion in 'Shooting Gear and Storage' started by SDM, Jul 7, 2006.

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  1. SDM

    SDM Member

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    I’ve got a couple of hearing protection questions:

    What is the minimum recommended NRR? Right now the highest rating I’ve seen is 30dB, in the “AO Safety/ Peltor Bullseye 10” (I’m sure there are others with this rating as well). Am I going to get much higher than that? Does it even matter – where does the law of diminishing return come into play? For all I know 25 might preserve hearing just as well as 30.

    I’m not really interested in the electronic models. It would be nice but they seem to always be rated lower than similar non-electronic models. If there is a model that will give maximum hearing protection I would consider them though. I’m not going to sacrifice my hearing just to hear the repeated “Down 1”, “Down 3”, and “Down 5” from the IDPA scorekeepers.

    I ask these questions because I recently noticed the muff’s I’ve been using have a rating of 21 and it seems I could do better. Thanks folks.
     
  2. Jim Watson

    Jim Watson Member

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    The more protection the better.
    Take 30 dB off a 140 dB gunshot and it is still too loud by OSHA standards.
    A lot of people wear plugs under muffs.
     
  3. Waitone

    Waitone Member

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    I use highest rated muffs and plugs I can find. Reason is simple. One it is gone it is gone. Eye and hearing protection is no place to get cheap or cavalier.
     
  4. hso

    hso Moderator Staff Member

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    The recommended NRR is whatever you need to get the noise level for the exposure time below the numbers in table from 29 CFR 1910.95 -

    TABLE G-16 - PERMISSIBLE NOISE EXPOSURES (1)
    ______________________________________________________________
    |
    Duration per day, hours | Sound level dBA slow response
    _____________________|_________________________________
    |
    8................................| 90
    6................................| 92
    4................................| 95
    3................................| 97
    2................................| 100
    1 1/2 ..........................| 102
    1................................| 105
    1/2 ............................| 110
    1/4 or less..................| 115
    _____________________|________________________________

    This means that you subtract the NRR from the sound to get the exposure. Since most firearms are well above 130dBA an NRR 30 protective device (plugs or muffs) reduces exposure to no better than 100 dBA. The table from the OSHA standard would then permit an exposure of 2 hours. 140 dBA - 30 dBA = 110 dBA with an acceptable exposure of 30 minutes. 145 dBA - 30 dBA = 115 dBA with an acceptable exposure of ~15 minutes. 150 dBA has an acceptable exposure of ~7 minutes if using NRR 30 protection.

    As a rule of thumb your shooting/safety glasses reduce ear muff protection by about 5 dB. Plugs obviously don't have this problem.

    I use 30 plugs under electronic muffs so I can clearly hear voices without the shooting damaging what little hearing I have left. Gives me an effective 35 dBA protection.

    There have been extensive discussions of hearing protection and hearing protection devices in previous threads if you want to read more. http://www.thehighroad.org/showthread.php?t=201400&highlight=noise+hearing
    http://www.thehighroad.org/showthread.php?t=201116&highlight=noise+hearing
    http://www.thehighroad.org/showthread.php?t=190859&highlight=noise+hearing
    http://www.thehighroad.org/showthread.php?t=183414&highlight=noise+hearing
    http://www.thehighroad.org/showthread.php?t=183292&highlight=noise+hearing
    http://www.thehighroad.org/showthread.php?t=171869&highlight=noise+hearing
     
    Last edited: Jul 7, 2006
  5. Trebor

    Trebor Member

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    Hearing loss is cumulative and permament. If you shoot often, get the highest rated hearing protection you can find. I reccomend both plugs and muffs. As a general rule, figure that you have the base protection of whichever is highest rated and then add another 5 db in reduction for the fact that you have doubled up by wearing both.

    I wear Peltor Ultimate 10 muffs rated at 30 db. I almost always wear plugs underneath them. I find the cheap yellow cylindrical plugs work the best. They aren't as highly rated as other plugs, but are easier to use correctly, so I think I'm getting more protection then if I was using higher rated plugs that weren't inserted properly.

    If I'm having trouble hearing range commands, I'll loosen or take out the plug on the side nearest the range officer. That still leaves me with the muffs.

    Having plugs on underneath also reduces the chances you'll get caught without any hearing protection when someone fires unexpectedly. It's happened to me a few times over the years. I generally leave my plugs in even when I've removed the muffs until I absolutely, positively, 100% sure there all the guns are put away or I'm off the range.

    Protect your hearing as much as you can. You won't notice the little losses here and there right away, but it adds up, and you'll notice the effects later in life. There are a lot of older shooters who are deaf or nearly deaf from back when people didn't normally wear hearing protection.
     
  6. rangerruck

    rangerruck Member

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    i do wear plugs under my muffs, and it def takes out any remaining high pitch. you can never get hearing back.
     
  7. One of Many

    One of Many Member

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    Every shooter needs to wear Eye protection, and that usually means eyeglasses with temple pieces that pass under the cups of earmuffs. That reduces the effctiveness of the earmuffs by about 5 dB. Adding earplugs underneath the earmuffs, adds about 5 dB of protection, so you get back to the original rating of the earmuffs.

    The best current earmuffs run in the 30 to 31 dB range; these are large, bulky units, that typically do not fold up for convenient pocket sized storage. I would rather have the best hearing protection available, than the easiesr storage of a lessor protective product.

    Electronic earmuffs usually have a significantly lower NRR rating than regular earmuffs. The electronic units limit the amplification of impulse noise to around 85 dB, but the noise leakage through the shell is greater than that; 140 dB impulse noise - 25 dB NRR is115 dB impulse noise, which exceeds the 85 dB electronic limiting - you are still being exposed to 115 dB of impulse noise in this example.

    The amplification circuits usually have enough power to exceed safe noise limits for non-impulse noise. You can damage your hearing by setting the volume level higher than safe limits, just like the people that wear their portable sterio players and have them loud enough that everyone passing them on the sidewalk can hear the music they are listening to.
     
  8. 2clip1

    2clip1 Member

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  9. LWS32

    LWS32 Member

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    Plugs & Muffs for me.
     
  10. ALHunter

    ALHunter Member

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    while we are on the topic, what recommendations are there for quail/pheasant/dove hunting? Typically I am walking a field for half to a whole day. The shooting of birds is punctuated by anywhere from 10-30 minutes of walking & running the dogs until they get on point. Similarly, for dove, shots can be 10-60 minutes apart depending on how they are flying and feeding.

    I want to be able to converse at a normal tone with my fellow hunters during the lulls in shooting. What do you usde in such situations? Plug up once the dog gets on point or you see the doves on the horizon?

    I shamefully admit when bird hunting I am presently not using any protection. But, I do want to change that. Just looking for:
    1. something comfortable for extended wear in the field;
    2. provides very good noise reduction; and
    3. still allows me to hear to converse with fellow hunters
     
  11. Soybomb

    Soybomb Member

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  12. the naked prophet

    the naked prophet Member

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    Keep in mind though, that a gunshot is a very, very short duration noise. Even with a very generous 0.1 seconds each, you're only up to 3 seconds duration with a 30 round magazine. At 120 dB (150 dB - 30 dB muffs) you've got 7 minutes - that's 4200 rounds. Most gunshots, even in a badly echoing room, are closer to 30 ms than 100 ms (I did this experiment in an acoustics class - we fired a .32 revolver in a church! With microphones and acoustic equipment, of course).

    However, many people lose their hearing from other sources and blame it on shooting a lot. My grandfather was in WWII and his hearing was fine... until he worked at a trainyard. I do use plugs and muffs when shooting. Overkill doesn't hurt anything, and caution is the word of the day. But I also wear muffs when I'm vacuuming, mowing, or doing anything at all in a noisy environment. Wearing muffs (assuming you're not shooting anything really big or ridiculous like a SBR .308) will probably be fine, just remember to protect your hearing from other sources of danger as well.
     
  13. hso

    hso Moderator Staff Member

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    2clip1,

    Welcome to THR!
     
  14. Soybomb

    Soybomb Member

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    naked prophet: I would point out that it doesn't seem to be so cut and dried as simply measuring time, it seems impulse exposure can also do damage even if total sound duration does not exceed what would be thought of as a safe time. You say your grandfather's hearing was fine after ww2. Did he have it tested or did it seem fine?

    http://archfami.ama-assn.org/cgi/content/full/9/4/352 here is a study that might be a good one to start out and check out its references on.
     
  15. hso

    hso Moderator Staff Member

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    Soybomb's correct. Simply noting that the duration of a gunshot is very short doesn't accurately reflect the physiological impact it has. The recovery time is an important factor in hearing damage and recovery. While the duration of the sound impulse my be short the effects continue for some time. Repeated intense exposure, even though short, will have a cumulative effect. Think of it as walking across a grassy lawn. Do it once per week and it still recovers. Do it repeatedly it doesn't have time to recover and it dies. Keep hammering at your hearing without allowing for recovery time and you will suffer hearing loss.
     
    Last edited: Jul 7, 2006
  16. hso

    hso Moderator Staff Member

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    Last edited: Jul 7, 2006
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