Earplugs, Do They Live Up to Their NRR?

I have tried various kinds of ear plugs, but they never really feel like they live up to their claimed NRR to me. They claim 33 dB noise reduction, but it doesn't seem like that much. I recently got earmuffs that are rated 30db noise reduction and they reduce noise so much greater than the 33 dB ear plugs.

Does anyone else have issues with ear plugs? Maybe my ear canals are just larger or oddly shaped that ear plugs don't fit well. I work in an area where there are a lot of loud noises and with my new tinnitus and hyperacusis hearing protection is a must.

 

You have too push them deep.

 

I like the tree like ones and slightly twist them as I put them in.
No problem with them....lots of love glynis

 

I found ear muffs to be better but some ear plugs are good too.
It's not always easy to put plugs deep and well seated.
Muffs are easier to get used to and less irritating when wearing them for extended time than plugs unless it's very hot.

 

How does NRR change decibels of exposure?
When hearing protection is worn, your level of exposure to noise is based on the NRR rating of the protection device being used. Keep in mind, however, that while the NRR is measured in decibels, the hearing protector being used does not reduce the surrounding decibel level by the exact number of decibels associated with that protector’s NRR. For example, if you are at a rock concert where the level of noise exposure is 100 dB and you are wearing earplugs with an NRR 33dB, your level of exposure would not be reduced to 67 dB. Instead, to determine the actual amount of decibel deduction applied (when decibels are measured dBA which is the most common), you take the NRR number (in dB), subtract seven, and then divide by two. Given the previous example, your noise reduction equation would look like the following: (33-7)/2 = 13. This means that if you are at a rock concert with a level of noise exposure at 100 dB and you are wearing a hearing protector with an NRR 33 dB, your new level of noise exposure is 87 dB. If you are wearing a product with an NRR of 27 it would deduct 10 decibels (27-7/2=10).

 

It completely depends upon the seal formed in your ear. If the seal is tight and you follow the insertion depth guidelines, then you will benefit from the full lab tested reduction.

However, if the seal has a gap, or the overall fit is not so good then you won't get the full benefit, and the equation posted by Bobby above seems to be the go to formula. It is only an mean estimation though.

Musician ear plugs will give you the full reduction because they are specifically made for your ears.

That reduction also takes into account all the people who don't insert the plugs properly. If you roll and deeply insert the foam ones, such as hearos, you will most likely get the full reduction. The problem is when people mis use them and only push the tip into their ear.

 

Are you 100% sure about that?

 

What about post below? Do you get full nrr benefit if you fit the plugs properly?

 

Lol, old thread. But I did find out my ear canals are larger than normal hence I didn't get a good seal no matter how deep I would place them in.

A way I came up with for estimating the noise reduction you are getting is by using a hearing test app and headphones. Determine your hearing threshold, then put in earplugs and put the same headphones on. If you have to raise the sound level about 30 db above your threshold then that's a good estimate of the reduction you are getting.

 

Yea. The reduction numbers are created in a lab under perfect conditions, but what you find in the real world is not exactly perfect. Everyone's ear canals are different sizes and shapes, so you are relying on the foam plugs to expand and completely seal off your ears. In some cases this may leave a gap or it may not be possible to roll and insert the plugs deep enough. Then you have the instances where people just don't use them properly and have them half hanging out their head.

Custom plugs are more comfortable and are made to fit your ears. Whatever specs they state should be what you are getting. If you use a blanking cap instead of a filter you should get around 30db reduction in sound.

Just to add to above, have a read through these:

http://c.ymcdn.com/sites/www.hearin...16_Conference/Presentations/Alberto_Behar.ppt
http://www.protectear.com/nrr-rating/
https://www.magidglove.com/nrr_snr_defined.aspx

One excerpt that gets to the point is this:

Another single number rating is based on (Subject Fit) Real Ear Attenuation measurements, known as Single Number Rating (Subject Fit 84th percentile) and abbreviated as SNR (SF 84) (for details see ANSI Standard S12.6). “SF 84” indicates that 84% of the users in a well run hearing conservation program are expected to receive at least that much protection.

This is the plug I use; although I have 3 different filters:

http://www.hearingprotection.co.uk/images/stories/ACSPRO-26.pdf

 

After searching around I found some interesting details about earplugs I think a lot people are not aware of.

1) Earplugs attenuate higher frequency better than lower frequency. For example, a NRR 30dB rating earplug, which sound very high, only reduce a sub 100hz noise by around 20dBs.

http://multimedia.3m.com/mws/media/711117O/3m-e-a-r-classic-earplugs-datasheet.pdf


2) NRR rating is a theoretical best case scenario. Most people will fall well short of that NRR rating in real life scenarios. For example if your ear canal is smaller volume than normal like mine. The foam earplug will stick out and the rating wont be accurate. Or if it didn't firm a 100% air tight seal, the ratings goes out the door.

Earplug manufacturers like 3M recommend you to derate the NRR. To find the real life NRR you take the (rated NRR - 7) / 2. So a 31dB NRR is closer to 12dB reduction if you don't have the optimal physiology or know how to use it properly

http://multimedia.3m.com/mws/media/...how-to-use-the-noise-reduction-rating-nrr.pdf

Why this is important:

Some people will assume look at a earplug and just take the noise level - NRR. So they would assume (as I did) at a 110 dB concert they will recieve 30dB of protection making it 80dB, within the safe limits. But when I was at the concert 2 weeks ago, using frequency analyzer I found the highest noise level was actually the 75Hz bass.

This means at BEST the plugs will give you 20dB protection at that frequency. Then if you are taking into account the suggested de-rating for real life performance. It is more like 10-15dB reduction. Which means you are exposed to not 80dB at a concert, but 95-100dB noise for hours.

TLDR. don't assume you will get a 30dB reduction based on a 30dB NRR earplugs

 

Hey, yes you are correct. I mean safety raiting on earplugs is limited to their spescifications, i would not look for anything beyond that (regards 75Hz bass, i think you need to add some sort of "metal" filling to foam earplug to bounce that off), however if used properly - they work.

I can also vote for that foamies perform different based on manufacture/model and would say that absolute best so far are Howard Leight MAX 33Db NNR. I compaired them to Moldex Sparkle(?) 33Db NNR and can say that HL Max work better.

 

Very interesting.