Scott Lake writes in response to our recent Question of the Day: Have You Ever Forgotten Hearing Protection?
In the interest of full disclosure, I work for Westone Laboratories – makers of DefendEar lab designed and manufactured custom hearing protection [as above]. I work on both ANSI and CSA standards development committees for hearing protection testing, qualification, etc. I’m also on the Executive Council for the National Hearing Conservation Association.
There’s a whole lot of misinformation on when one should and shouldn’t wear hearing protection – some of it repeated in this discussion thread. The National Institute for Occupational Safety and Health is probably the most authoritative resource in the country as it pertains to hearing loss, and has the most concise description of the damage risk criteria for hunters and shooters. Their website addressing this topic recommends double protection (muffs over earplugs), and they don’t say that it’s o.k. to shoot a .22 without, but make sure that you wear it for everything else. NIOSH’s page states that not only is the damage potential related to the peak impulse, but it’s also related to how many shots one shoots per day . . .
You should also be aware that there is pending change to the EPA ruling for the labeling of hearing protectors which includes a rating of how the protector works for impulsive noise like gunshots. I can say authoritatively, that the NRR is really pretty meaningless as it pertains to gunshot noise. If you’ve ever had your hearing tested (which I highly recommend), then you are familiar with a process similar to that used to determine the NRR – hearing is tested with an without earplugs in place and the difference between the two sets of data are used to calculate the overall protection (average attenuation and standard deviations from a group of 10 test subjects, 3 rounds of testing each are used.
If you’d like to see how the NRR is calculated, it’s available as the first 2 pages of this .pdf.
These low level noises used to determine NRR are not representative of the highly impulsive nature of gunshot noise – where hearing protection behaves non-linearly from an acoustics standpoint. In 2010, ANSI released S12.42-2010 which includes a provision for measurement of impulsive noise reduction. The test data from that portion of the standard is used to calculate Impulsive Peak Insertion Loss, or IPIL. This test metric provides a much more representative measure of the potential attenuation for a hearing protector as it pertains to gunshot noises.
Very few manufacturers have tested their products for this as it is a relatively new test standard and there are only a couple of locations nationwide where the test can be conducted. We have this test data for our DefendEar Digital series of products as well as our DefendEar Hunter Passive, with plans to test even more of our hearing protectors in this fashion. We should soon have an article addressing this topic on our website.
Another topic that has reared its head in this discussion is that somehow one’s body protects itself against gunshot induced hearing loss. The Veteran’s Administration really wishes that these statements were correct, as they have paid out quite literally billions of dollars over the years to outfit veterans with hearing aids due to gunshot noise induced hearing loss. This report shows that hearing loss and tinnitus are some of the biggest claims that the VA has to pay, both from sheer numbers of persons suffering as well as the financial outlay. Several pages of that report address this issue.
In the meantime . . .
Don’t forget your earplugs and earmuffs and even more importantly, wear them properly. Improperly worn hearing protection is rampant. If you choose to wear a generic fit earplug, make sure to check with the manufacturer’s directions on how to fit them properly. Make sure that the product is the right size for you. I had a customer tell me his custom hearing protection was much less comfortable than his generic ‘bullet shaped’ foam earplug. Then he showed me how the foam earplug inserted without having to roll it down! He wasn’t getting any protection from that plug.
Roll the foam down so there’s no fold-over to it – hold it in while it expands. To test whether it’s really working, begin talking in a normal speaking voice and slowly raise an open palm hand past your mouth while continuing to talk and toward your ear (like an old-time radio announcer). You shouldn’t be able to hear a change in the sound with a solid foam or silicone hearing protector, as you raise your hand toward your ear.
Enjoy shooting the rest of your life – wear proper hearing protection – always.