Time for the critical review part of this post. (and some math, sorry for the math)
For general shop use I think these Eye Muffs are great. But, they don't have the highest Noise Reduction Rating (NRR) out there, and that could be a concern to some.
In regards to their NRR (Noise Reduction Rating),they are only rated at 19dB. So, what is NRR and what does that really mean in the real world.
Noise Reduction Rating is basically a unit of measurement of noise reduction, simple right. Well, most of the time when I hear someone talk about NRR they don't really understand what it means or how to apply it. The biggest mistake is that people think that the NRR dB number is the actually amount of dB reduction, this is not correct. Here is a quick crash course on NRR and how it applies to life in the shop.
First, let me give some examples of Decibel Ratings.
30 dB = Whisper or Quiet Library
60-70dB = Human Conversation
80-120dB = Ratings on Most Power Tools (these are from my workshop verified from an OSHA inspection)
120-130dB = Threshold of Pain
188dB = Loudest Animal Alive the Blue Whale (look it up, I didn't believe it either)
Now that we have some numbers to work with, how much reduction does a set of Eye Muffs, or any hearing protection really give us. For these examples lets pretend we are using a thickness planer running at 110dB.
The formula goes like this, dB of machine - (NRR-7)= estimated exposure level in dB
Example for the Eye Muffs using a thickness planer at 110dB.
110dB - (19dB-7)= 98dB , only a reduction of 12 dB, doesn't seem like very much does it. Plus, look at the OSHA recommendation above. You can only use that tool for 3 hours or less. I think we can do better than that.
Lets look at my previous set of hearing protection.
110dB-(30dB-7)=87dB a reduction of 23dB (almost twice the level of the Eye Muffs) and we got below the 90dB mark, so we can work longer without worrying about our ears.
The best you can do is maybe wear two forms of hearing protection, but the math is a little different. Lets say you are wearing foam 3M yellow classic Ear plugs NRR 30dB and Eye Muffs at 19dB.
Formula goes like this. Take the highest NRR rating, subtract 7, then add 5. Take that number and subtract it from the machine dB level. The answer is the actual dB level hitting your eardrums.
dB of the machine - (Highest NRR -7)+5 = exposure level of dB
110dB thickness planer - ((30dB-7)+5) = 82dB to your ears. Total deduction of 28 dB.
I guess my point with this review, Algebra flashbacks, and information, is to say this. In general, most hearing protection reduces the total dB level's enough to protect your ears, depending on what machines you are using. Some are better than others for sure, and doubling up is even better. I leave it up to you to determine what you actually require. Just remember, almost no hearing protection is really going to help if you are around a Blue Whale when it decides to whistle at 188dB.
For me, I'm still going to use the Eye Muffs for most thing, except the thickness planer because it is just to darn loud.