Hearing protection - Is there a Doctor in the house?

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This is a Hearing Protection Question


I'm new to shooting. I have about 600 rounds under my belt. 400 indoor, and 200 outdoor approx.

For most of those rounds (500) I wore 33 NRR plugs with 26 NRR Electronic Muffs.

I look at the specs (9mm) and read that they can reach levels of 160db!

By 'Doubling up' I'm not getting 59dB's of protection....

Maybe 37 or 38dB's, Not to mention the fact that dB levels are logarithmic and every 3db's equals a DOUBLING of sound pressure!

I double up, and I still can't see how I'm not causing permanent hearing loss.

Any thoughts?
 
Not a doctor (med student, just know enough to be dangerous), so take this for what it's worth.

http://www.cdc.gov/NASD/docs/d001001-d001100/d001068/d001068.html

LIMITATIONS OF PROTECTION

As with most personal protective devices, HPDs have limitations. Improperly worn HPDs may not reduce the noise levels to within acceptable levels and tend to cause a false sense of security. Wearing both plugs and muffs at the same time will reduce the amount of noise exposure. However, the additional reduction from wearing both devices will be only 6 or 7 decibels, even if the NRR for both devices is above 25.
Click to expand...

On the up side, gunshots are over very fast. On the down side, the muscles in your ear don't have time to dampen the sound for you.

Hopefully a real doctor or audiologist (not that they aren't "real doctors" too) will weigh in.
 
I double up, and I still can't see how I'm not causing permanent hearing loss.
Click to expand...

First the bad news: You probably *are* suffering some slight, permament hearing loss, even with hearing protection on. As you noticed, the db reduction is not as great as the db generated by the gunshots.

Now the good news: Since the *duration* of the gunshot is so small, the amount of hearing damge you sustain under your hearing protection is also very small. That level of noise reduction provided by your hearing protection, especially when high db rated protection is doubled up, is enough to protect you from the majority of the effect of the quick noise impulse of the gunshots.

It would be a different story entirely if you were exposed to say a jet engine or jackhammer that produced noise equal to that of a gunshot. The longer duration of those noises would make them have a more significant effect, even if the volume was the same.

As you've discovered, the best solution is to wear the highest rated protection you can find and to improve that by "doubling up" with muffs and plugs.

Btw, stick a pair of plugs in your pocket as well. Their really handy to have when you run across unexpected loud noises in your day to day enviroment. Things like loud construction outside your office window, or a snoring room mate on a business trip, or a million other things.
 
also try googling this,

Navy hearing pill


it works

and doubling up on ears will work for long term protection. I spent two summers sitting on concrete mills, IE road surface recyclers, foamies and muffs kept me ok after hundreds of hours at 140 + DbA. I was loud enough that it physically hurt to not have plugs and muffs in, but with them i was fine.
 
Damage is caused by DB over TIME. Gunshots are very loud but not for long durations.

If you're using foam earplugs properly (I use Howard Leight Max), i.e., rolling them REALLY small, pulling up on the top of your ear with the other hand, and inserting them until they feel like they're touching your brain, THEN putting earmuffs over the top of that...

I can't see how you're going to suffer hearing damage during a space shuttle launch, let alone target shooting.
 
160 dB at the muzzle is not what you're going to experience from the shooter's position.

As others have noted, noise levels are only half the equation, with duration of noise filling out the second half.

Shooting indoors can cause problems because of noise reflection (off barriers between shooting lanes. Moving forward a bit can help reduce you muzzle blast from your weapon... unfortunately it also makes you more vulnerable to muzzle blast from the weapons in the neighboring stalls.

jacob
 
Sounds of short duration will cause some damage, but it is much less than those of longer duration.
The point is not to reduce the noise reduction to zero, but below the threshold for permenant damage.
You don't want to be near the muzzle, where the noise is louder. But with a pistol you are further away - you hold it literally at arm's length. Air itself will muffle some of the noise.
Naturally if you are in an enclosed area, the noise reflects. Outside is better.
 
...

As said above, earplugs and Earphones/muffs combined. Do as little shooting indoors as you can avoid, and for God's sake, if you go indoors and there's anyone in there with a full 44 mag.. Leave

Indoors or outdoors (way better on the ears) try and go when least crowded if possible, and move furtherest away from other shooters, especially anyone with a 44mag.. lol (really)

Whisper when you talk to others, makes them listen more.. lol


LS
 
I believe the maximum daily exposure to impulsive noise of 140 dB intensity is 100 times. So if your hearing protection reduces gunshots down to 140 dB, you're safe to fire 100 shots per day. If it's less, then the number of shots goes up.

If you figure on 40 dB reduction, that means most pistols would go down to 120-130 dB, and high powered rifles should still be a bit under 140 dB.

Don't forget that many dB figures for gunshots are measured 1 meter directly to the side of the muzzle (usually the left), which will be much louder than behind the gun.
 
I'm a hearing aid technician and my wife is an audiologist. Hope those qualifications are good enough:D

Essentially, there are two things to consider. First, bear in mind that you are not generally exposing yourself to the maximum impulse of the gunshot, even if you are in an indoor range. You are not holding the muzzle next to your ear; therefore you are not being exposed to as much sound as you may believe. The accepted maximum figure for gunshot noise as actually experience by a shooter is 140 to 150 dB. This means that a shooter with decent ear protection is going to be exposed to impulse sounds of 110 to 120 dB.

The second thing to consider is that, as has been pointed out, duration of exposure is an important factor. OSHA standards hold that 80 dB is the threshold at which hearing damage begins. At 90 dB, one can expect damage after 8 hours of constant exposure. For every additional 5 dB increase, the allowable time is cut in half: 95 dB for 4 hours, 100 dB for 2 hours, etc.

By running the numbers, then, we see that 110 to 120 dB is "OSHA acceptable" for 15 to 30 minutes. Considering that a gunshot lasts for milliseconds, it seems as though you can cram in quite a bit of shooting before damage begins. (This does not hold true as we reach and exceed 140 dB, BTW. That is the pain threshold for most folks and is where the risk of instantaneous damage begins.)

The bottom line is this: if you experience threshold shift (a temporary hearing loss) or temporary ringing in the ears after a shooting session, your ears are warning you of impending damage. If you do not -- and I personally don't even after hours of magnum shooting at an indoor range -- then your hearing protection is effective.

HTH!
 
.38 Special

If you don't mind me asking....

What kind of protection do you use?


Thanks!
 
For outdoor ranges I generally use a set of 31 NRR muffs. For indoor I add a set of custom plugs that test out at an actual -- as opposed to whatever is written in the manufacturer's commercials -- 19 NRR.

I haven't tested the combination of plugs with muffs but figure the combined actual NRR should be in the neighborhood of 35-40 dB.
 
Facts on noise levels:

Decibels measure sound pressure and are logarithmic. That means that only a 3db increase almost doubles sound pressure, a 6db increase quadruples sound pressure, etc.

Gradual hearing loss may occur after prolonged exposure to 90 decibels or above.

Exposure to 100 decibels for more than 15 minutes can cause hearing loss.

Exposure to 110 decibels for more than a minute can cause permanent hearing loss.

At 140 dBA noise causes immediate injury to almost any unprotected ear.

There is also the more extreme ‘acoustic trauma’, which is an immediate loss of hearing after a sudden, exceptionally loud noise such as an explosion.

From: http://www.healthsystem.virginia.edu...aring-loss.cfm

“When someone goes to a concert, cuts grass or runs a power saw, they can suffer from NIHL,” said Dr. George Hashisaki, assistant professor of otolaryngology at the University of Virginia Health System. “Afterwards, if their hearing is muffled or their ears are ringing, they have suffered NIHL. Even if their hearing comes back to what they perceive as normal, a small part of that hearing loss is permanent."

"People who are most in jeopardy of losing their hearing are those who use firearms regularly without ear protection or who are in the military and unable to wear hearing protection, such as those on the frontlines, Hashisaki said. The noise level of gunshots can reach 170 dB and is capable of immediate damage. Hashisaki recommends wearing both earplugs and earmuffs to protect hearing while target shooting."

Comparative noise levels and corresponding damage

12 gauge shotgun 165 dB Instant damage
Jet engine taking off 140 dB Instant damage
Thunder/Ambulance siren 119 dB 3 minutes
Hammer drill 113 dB 15 minutes
Chain saw/Earphones/Concert 110 dB 30 minutes
Bull Dozer 105 dB 1 hour
Tractor/Power tools 96 dB 4 hour
Hairdryer/lawnmower 90 dB 8 hours





Here are some examples of noise levels:

Video arcades - (110 dB).

Firecrackers - (125-155 dB at a distance of 10 feet).

Live music concerts - (120 dB and above).

Movie theatres - (118 dB).

Health clubs and aerobic studios (120 dB).

Sporting events (127 dB).

Motorboats - (85-115 dB).

Motorcycles - (95-120 dB).

Snowmobiles - (99 dB).

"Boom cars" - (140 dB and above).

Here are noise levels of firearms:

.223, 55GR. Commercial load 18" barrel 155.5dB

.243 in 22" barrel 155.9dB

.30-30 in 20" barrel 156.0dB.

7mm Magnum in 20" barrel 157.5dB.

.308 in 24" barrel 156.2dB.

.30-06 in 24" barrel 158.5dB. In 18" barrel 163.2dB.

.375 18" barrel with muzzle brake 170 dB.

.410 Bore 28" barrel 150dB. 26" barrel 150.25dB. 18" barrel 156.30dB.

20 Gauge 28" barrel 152.50dB. 22" barrel 154.75dB.

12 Gauge 28" barrel 151.50dB. 26" barrel 156.10dB. 18" barrel 161.50dB.

.25 ACP 155.0 dB.

.32 LONG 152.4 dB.

.32 ACP 153.5 dB.

.380 157.7 dB.

9mm 159.8 dB.

.38 S&W 153.5 dB.

.38 Spl 156.3 dB.

.357 Magnum 164.3 dB.

.41 Magnum 163.2 dB.

.44 Spl 155.9 dB.

.45 ACP 157.0 dB.

.45 COLT 154.7 dB.

Factoid

Properly fitted earplugs or muffs reduce noise 15 to 30 dB. The better earplugs and muffs are approximately equal in sound reductions, although earplugs are better for low frequency noise and earmuffs for high frequency noise.

All of us should be trying to get the greatest Noise Reduction Rating (NRR) that can be put together. NRR 30 plugs with NRR 20 muffs will give you an effective NRR 45 (add plugs and muffs, then subtract 5). If noise levels are 160 dB this gives you an exposure with plugs and muffs of 115 dB. The acceptable exposure time for this is 15 minutes total for the day. If the noise levels are 150 dB the resultant acceptable exposure time with the given plugs and muffs is 1 hour and 4 hours if the noise level is 140 dB. You're not going to find unsuppressed noise levels below 140dB with gunfire.

If you are shooting by yourself, roughly 100 rounds of 140 dB instantaneous noise in a day should not produce hearing damage. Put your plugs and muffs on and you get to shoot up to a thousand rounds without damage (louder ammo/gun and the allowable drops by a factor of 5). Shoot with other people and you have to add all the rounds shot cumulatively (10 people shoot 100 rounds and everybody's done for the day; toss a handcannon or 30 cal rifle in and you're back down to 200 rounds cumulative). If you shoot on an indoor range then all the rounds fired while you are on the range go into your total. So you can see that it doesn't take very long on a range to have a thousand rounds popped off around you.

If you want to know what the noise level you are exposed to is you can rent noise dosimeters that you can wear. They will record the total noise exposure and present the information to you as dB. You can then subtract the adjusted combined NRR of your hearing protection to determine if you're getting too much exposure.

LINKS

http://www.deafnessresearch.org.uk/N...+loss+1640.twl
http://www.healthsystem.virginia.edu...aring-loss.cfm
http://www.audiologyawareness.com/library.asp
 
Thanks for all the well thought replies.

This is an issue that keeps me up at night.

Hearing loss is a deal killer when it comes to this particular hobby. I want to get all the facts I can.

Home Defense... Another matter completely....;) :cool:
 
NRR 30 plugs with NRR 20 muffs will give you an effective NRR 45 (add plugs and muffs, then subtract 5). v
Click to expand...

This is no longer the accepted approach and fell out of favor over 2 years ago. You no longer add the NRR of the plugs and muffs and subtract 5 dB. Instead you take the higher of the two and add 5 dB to that. 30 plug with 20 muff gives an effective NRR of 35 not 45.

Impact noise, like that from gunfire, is fundamentally different from constant noise, but the damage it does is based on the SPL and the time exposed to the SPL just as with constant noise. The difference is that the rate of exposure and peak levels are the controlling factors in hearing damage to impact noise. Peak levels should not exceed 140 dB without protection. The Army lists it's 9mm handgun and the M16 as producing a peak noise of 157 dB (http://chppm-www.apgea.army.mil/hcp//NoiseLevels.aspx. The plugs and muffs combination would effectively reduce the exposure to 125 dB (assuming the unlikely ideal insertion of the plugs and the proper use of muffs). Should the plugs not be properly inserted protection can be as little as 10 dB resulting in an exposure of ~167 dB.

http://www.combatindex.com/mil_docs/pdf/std/1400/MIL-STD-1474D.pdf is the military standard for noise exposure including impact noise like gunfire. See pages 35, 36 and the table on 38 for impact noise exposure limits in use by the military. Here are the relevant tables extracted from the document. Note that noise from firearms will as a minimum be an X category noise after the hearing protection composite NRR is applied. The Y would be the category I would act on for a range session.
 

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The list missed NHRA funny car, Something like 180 DB at launch at the side pipes.
 
As long as we are on this extremely important topic, a question please.

I always read about the dB reduction with a "properly fitted" ear muffs. Realisticly speaking how well do they work while wearing safety glasses?:confused:

NukemJim
 
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