“Huh..?” How hearing protection works (or doesn’t).
One day in the late 90’s I went shooting with some friends from work out on a piece of rural property one of them owned a little east of Cincinnati, Ohio. I remember my hearing and eye protection drew a guffaw from one old timer who made some remark to me about just having to “toughen up my ears,” to which I responded “isn’t that called hearing loss?”
I have almost 20 years of professional experience protecting people’s hearing in the workplace. I could go into all kinds of scientific details about the effects of impulse noise on hearing, but that wouldn’t be helping the “too long, didn’t read” crowd – you know who you are. So here’s the quick and dirty version:
There are 2 ways to prevent sound from entering the ear canal:
1. Insert something into the ear canal
2. Place something over the ears
In both categories there are a number of devices that can be used, ranging in effectiveness from “not at all” to “pretty damn good.” Here’s how it works:
- Silicone “pre-molded” ear plugs insert into the ear canal. They have a series of baffles that block sound from entering that provides an average noise reduction rating (NRR) generally in the 22-26 dB range. They are a custom fit device, and may not provide adequate protection if the correct size is not used. They are meant to be reusable, so they can accumulate a buildup of earwax and debris. Wash them after every use with soap and water or you’re asking for an infection. Electronic versions are available that amplify quiet noises and shut off loud noises.
- Foam plugs are compressed, inserted, and held into place until they expand and seal off the ear canal. They have a typical NRR in the 28-33 dB range. They are cheap and disposable, and potentially the most effective form of hearing protection IF they are worn correctly.
- Wax plugs are available for swimmers and light sleepers that consist of a soft blob of material that can be pressed into the ear. These provide minimal noise reduction, maybe 5-10dB and are not at all suitable for shooting. The wax gets contaminated quickly and is just gross.
- “Custom” ear plugs are available by having a technician squeeze goo into the ear canal that cures into a flexible mass that supposedly provides a custom fit for the user. The problem with most of these is that they have no noise reduction rating or testing performed which means you don’t know how well they are doing their job. There are some high quality versions available that do have laboratory certified noise reduction ratings, but these aren’t the kind you get made in 15 minutes at the local gun show, and they can be hundreds or thousands of dollars depending on what features you want (like electronics).
- “Ear muffs” cover the external structure of the ear and seal to the side of the head with a foam or plastic padded gasket of sorts. Ear muffs are available with noise reduction ratings as low as 16 dB and as high as 30 dB and are also available with electronics.
- Improvised hearing protection like cigarette butts, empty pistol brass, and cotton balls provides no protection whatsoever.
So that noise reduction rating is pretty handy. If I’m shooting a 150 decibel AR-15 and wearing earmuffs with an NRR of 25dB, I’m only getting exposed to 125 dB every shot, right? Not so fast…that NRR is just the laboratory prediction of the sound reduction obtainable by 98% of the population IF they wear the hearing protection perfectly. While you may be getting the full benefit of them, it’s far more likely that you’re not. For example: are you wearing eye protection? The stems of those shooting glasses are interfering with the seal on your ear-muffs and letting the noise leak in. Are you wearing those earmuffs over long hair or a hat that is interfering with the seal? When you get that tight cheek-weld on your rifle stock, is it pushing up the edge of your earmuff a little? You see, it’s pretty easy for this to go sideways. OSHA pretty much recommends that for single hearing protection like muffs, you should only count on getting half of the advertised NRR, which means those 25dB muffs are only taking off about 12 dB, and you are getting exposed to almost 140 dB of impulse noise every shot. That’s causing permanent damage.
Foam earplugs can be used without interference from shooting glasses or hats, that will do the trick, right? While it is possible to get the full NRR value or even more from foam plugs, they have to be worn 100% correctly, and based on my personal observations, a lot people don’t know how to do this. OSHA agrees, as they advise subtracting 7 from the NRR of foam plugs, THEN dividing the result in half. So the average effectiveness of a 33 dB plug is more like 13 dB when worn “average.” Not so hot.
What if you double up plugs and muffs? Well, that does improve things, but the result isn’t 2+2=4. The equation OSHA uses states that you can add about 5 dB of reduction by wearing plugs and muffs. That’s a minimum reduction of about 18dB and a max of 34dB. Wait, why only 34 dB? …because sound waves can enter the ear canal through the mouth and sinus cavity, the skin surrounding the ear, and even conducted through the bones of the skull. These physical structures only provide about 34dB of protection (give or take depending on physiology). You could stick a 100dB NRR plug in your ear (if such a thing existed), and you would still only get roughly 34dB of noise reduction because the sound will enter the body in other ways besides the ear canal.
In industry, OSHA makes employers follow a “hierarchy of controls,” meaning that noise should be reduced or eliminated first with engineering controls like mufflers or enclosures. Second, administrative controls must be used, like limiting the time of noise exposure in a given day. Only after these first 2 controls have been implemented are employers able to use personal protective equipment like earplugs or muffs to attenuate any residual risk. For shooters, what does that mean? Well, if you live in a state where you can own sound suppressors (silencers), engineering controls are an option for you. Fill out your Form 4, pay your $200, and put a can on that muzzle. Suppressors will drop the muzzle noise by 20 to 30 dB or more. Now that 160dB M-4 is somewhere closer to a polite 130-140 dB. Even a single hearing protective device like plugs or muffs worn with average attention to detail will take another 12 or so dB off of that, which means your ears are only getting 118-128dB every shot – still potentially damaging by the way, but much, much less so than a raw muzzle.
Even if you can’t afford or don’t want to mess with the paperwork of owning a sound suppressor, another engineering control you can perform that does everyone in the world a favor is to TAKE THOSE DAMN LOUD MUZZLE BRAKES OFF! Muzzle brakes vent the blast and noise directly at the shooters on your left and right. Yeah, I’m talking to you…the guy with the “Kaboomer-comp” on his pistol length AR-10. I know it doesn’t seem so bad to you sitting directly behind the rifle, but it’s making everyone else on the line feel like their head is exploding every time you yank the trigger.
There isn’t much we can do from an administrative standpoint, which takes us right on to PPE or personal protective equipment. My recommendation when shooting any centerfire handguns or rifles (unsuppressed) is to wear 33dB foam plugs, properly inserted, and a good a set of electronic earmuffs. You will be getting the highest protection possible and you will still be able to hear range commands.
If you are shooting suppressed firearms, I would recommend a good pair of electronic earmuffs with an NRR of 26-30 dB (I like the Howard Leight Impact Pro 30dB electronic muffs).
That’s the basics, but at the end of the day guns are loud, even the cool suppressed ones. The so-called “hearing safe” suppressors just drop the sound pressure levels under 140dB, which OSHA says is more or less safe for a single daily exposure. Repeated firing of even suppressed firearms without hearing protection is going to mess up your hearing though. That ringing…buzzing…chirping sound you get after your range session? Eventually that doesn’t go away – and many of you reading this might be experiencing that already. So be a good example for the next generation of shooters with young, fresh ears. Use your PPE. Stuff a pocket of your range bag with foam plugs; they’re cheap and disposable. Share them on the range with other shooters, particularly young shooters who tend to forget their PPE in the excitement of a range trip. That’s being a good ambassador and part of the best the “gun culture” has to offer.