Questions About Hearing Protection

Discussion in 'Training & Safety' started by knfxda, Jul 25, 2011.

  1. knfxda

    knfxda New Member

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    So I have a bunch of questions about hearing protection...

    If you have any insight, details, or links to good information for any/all of this or questions of your own, please provide them!


    1. Without getting too sciency, can anyone explain NRR in layman's terms?

    2. Are NRR values linear?
      Meaning that an NRR of 26 is 1/25th greater than an NRR of 25. Or is it like the Ricter scale where larger numbers are exponentially larger?

    3. How much protection do you get from using both ear plugs and ear muffs?
      I know that it's not an aggregate value (33NRR plugs plus 25NRR muffs does not equal an NRR of 58). I know that there's a "formula"/rule of thumb for it, but don't remember what it is.

    4. How does NRR actually relate to gunfire?
      I believe NRR is generally designed around continuous noise and not peak noise.

    5. Are the molded earplugs better than the disposable ones?
      (Assume proper molding and proper disposable ear plug placement.)

    6. Can you simply add more/better foam to your muffs and get better ear protection?

    7. Why does 33NRR seem to be the highest rating?

    Now, my personal situation. I wear Howard Leight - Super Leight(R) Shooter's Earplugs (33NRR) and Howard Leight - Leightning(R) L1 Shooter's Premium Earmuffs (25NRR).

    I know that I can buy 30-33NRR earmuffs. What value would there be to getting the 33NRRs to wear over my 33NRR earplugs, if any? (Other than the overly simplistic - even though it might be right - more = better. I'd like something more "quantifiable".

    Thanks!
     
  2. dnthmn2004

    dnthmn2004 New Member

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  3. knfxda

    knfxda New Member

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    That's actually the source that I had for the "rule of thumb" for using both forms of protection. I really didn't like the information. It's overly simplified. The other stuff that I find is overly complicated. I was hoping for something in the middle. ;)

    And none of it is specific to shooting, which I'm finding is another issue. All of the info that I find seems to be about continuous not intermittant noise.
     
  4. dnthmn2004

    dnthmn2004 New Member

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    Hearing protection does not provide decibel reduction based on continuous or intermittent, just simply decibel level.

    That site provides answers to many of your questions.

    Are NRR values linear?
    No

    How much protection do you get from using both ear plugs and ear muffs?
    No formula, just +5-10 of the highest of the two.

    How does NRR actually relate to gunfire?
    It relates to all noise, continuous and intermittent.

    Are the molded earplugs better than the disposable ones?
    Depends on what you find comfortable and level of noise reduction.

    Can you simply add more/better foam to your muffs and get better ear protection?
    It would probably be easier and more effective to add ear plugs with your ear muffs. The only way to achieve higher than 33 is to use two kinds of hearing protection.

    Why does 33NRR seem to be the highest rating?
    The human threshold for hearing pain is about 130-140 decibels. If something is louder than 173 decibels (140+33), it has the potential to stop your heart. So they probably figure you don't need hearing protection if your going to die.:rolleyes:
     
  5. knfxda

    knfxda New Member

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    I'm probably being dense on this one, but I'm totally missing where you are getting this from. I see the "both give you 5-10 db additional protection" but that seems like a throw away "statistic". Well, which is it? 5, 7, 10? Is there even much of a difference between 5 and 10?

    In one section it says "In practice the protection that normally can be achieved is about 10-20 decibels." Well, then what the heck is an 33NRR if in practice only 10-20 can be achieved?

    In another section, it says "The effectiveness of earplugs is specified by a Noise Reduction Rating (NRR) typically ranging from 15-35 decibels". And that coms right before the 10-20 decibel limit statment.

    Oddly, my earplugs claim that NRR is measured between 0-30, yet they are rated as 33s?

    If NRR values aren't linear, then what are they? For example a 6.0 earthquake is 10X stronger than a 5.0 earthquake. So for every full point on the Ricter Scale, the strength is a factor of 10 stronger.

    *See why I'm confused?
     
  6. willshoum

    willshoum New Member

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    Say What!!!!!!!!!!!!!!!!

    If you ain't had your ears busted by the loud noises. WEAR EAR PROTECTION. Or go through the hell I go though every day an night. RINGING In the EARS.....:eek:
     
  7. Jake15

    Jake15 New Member

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    Seems like yall are trying to make this more complicated than it is, noise is noise, an NRR of 30db reduces the noise level 30 decibels, so when you shoot something that produces 160 decibel and your wearing a pair of plugs that have an NRR of 30 then your only gunna hear 130 decibels of noise
     
  8. knfxda

    knfxda New Member

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    Granted, more = better, and I knew that coming in, but I was hoping for something more in-depth than that. (How much more = how much better?)

    Let me distill it down further (my original questions still stand, though).

    When using 33NRR earplugs will there be any difference between coupling them with 25NRR earmuffs or 30-33NRR earmuffs?

    Is the extra 5-8NRR "improvement" simply "lost"?

    If I'm to believe the simple "add 5-10 NRR to the higher rated item" when pairing up protection, then I really should have found 10NRR earmuffs to go with my 33NRR earplugs, and I would have gotten the same protection as my 25NRR earmuffs or even 33s.

    ^^I have a lot of trouble with this.^^

    I get "diminishing returns" and I guess that's what's at play here, but it just seems like not a lot of bang for the buck in doubling up. (Anicdotally, I notice a very big difference when not doubling up, so I double up.)

    Oh and how much is a 5-10 dB improvement? I'm guessing that it's relative to where the noise level is, but I'd still like to understand it.
     
  9. rifleman1

    rifleman1 New Member

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    huh....what...speak up i cant hear you!!!
     
  10. knfxda

    knfxda New Member

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  11. willshoum

    willshoum New Member

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    Frustrated.......

    After reading all the post I have a feeling that the Gubment is looking for some earplugs but don't know what they are looking for in ear protection. KNFXDA you don't need 1,ooo pages of reports, gubment serveys, etc....... Just ask the people that know and has suffered and has learned from thier mistakes. Be safe, Be prepared.....