To calculate your new NRR rating, you won’t be adding the two NRRs together. You can increase your noise reduction rating with double hearing protection, like wearing earplugs with a headset. Wearing hearing protection is always recommended if you are around noise louder than 90 decibels. If I’m around heavy machinery with a decibel level of 110 (the sound level of a construction site), wearing the headset, the decibel level is now at 102. This shows that my headset will reduce the sound exposure by 8 decibels. Now I’ll divide that by 2 to get my final answer of 8. Using the equation above, I subtract 7 from the NRR rating to get 16. To calculate the actual number of decibels the hearing protector will reduce, we’ll use a simple formula.įirst, take the NRR rating number and subtract 7. These tests determine what the approximate rating is, give or take a 50% correction factor per OSHA’s recommendations. Hearing protection devices are to be tested and approved by both the Occupational Safety & Health Administration (OSHA) and the American National Standards (ANSI). The NRR rating is determined by various tests in laboratories. How is Noise Reduction Rating Calculated? Noise reduction ratings show you how much the device will decrease the decibel level. The higher the decibel level the louder the noise is. The higher the NRR rating on a hearing protector, the better is it at reducing noise. Noise reduction rating, commonly labeled NRR, is a unit of measurement that determines how effective a hearing protection device is at reducing sound exposure. Hearing loss is not fun and can be prevented.If you are around loud noise and wear hearing protection headsets, earplugs, or muffs, you might have heard the term noise reduction rating (NRR). LAWSUITS HAVE ALREADY BEEN RECOGNIZED FOR GUNFIRE NOISE THAT HAS RESULTED IN HEARING LOSS.ĪLWAYS CONSULT A PROFESSIONAL AUDIOLOGIST, OTOLOGIST, OR OTOLARYNGOLOGIST WITH YOUR HEARING PROBLEMS. BE SURE TO USE ADEQUATE EAR PROTECTION WHEN USING A FIREARM AND BE CAREFUL OF THOSE NEARBY. IF YOU INCORPORATE A PROCEDURE INTO YOUR SHOOTING THAT INCREASES THE SOUND LEVEL, YOU ALSO INCREASE THE RISK OF HEARING LOSS TO YOURSELF AND POSSIBLY THOSE WHO STAND NEAR YOU. AS THE SOUND PRESSURES INCREASE, SO DOES THE RISK OF PERMANENT HEARING LOSS. OUR WARNING IS SIMPLE AND IS IN THE BEST INTERESTS OF EACH SHOOTER. Imagine what the noise levels must be when we incorporate muzzle brakes or porting into firearms, or have a gun explode near the ear due to malfunction. No wonder we hear numerous reports about hearing loss as a result of firearms including acoustic traumas that take hearing completely as a result of one shot. The above averages are for all types of ammunition used in these firearms, and should be considered fairly representative. It should be noticed that this figure of 164.5 dB approaches the practical limit of impulse noise measurement capability inherent in most modern sound level meters. There was also a greater range, from 152.4dB to 164.5dB, representing 12 dB difference, or more than 10 time as much acoustic energy for the top end of the pistol spectrum. Krammer adds that sound pressure levels for the various pistols and ammunition tested yielded an average mean of 157.5 dB, which is greater than those previously shown for shotgun and rifle noise levels. This is approximately 14dB beyond the threshold of pain, and more than sufficient to cause acoustic trauma. Krammer continues to say that shotgun noise averaged slightly more that 150dB. Table-1-SHOTGUN-NOISE-DATA-DECIBEL-AVERAGES. Krammer, Ph.D., Ball State University, Muncie, Indiana has documented the following pressure levels. 357 magnum pistol, which can expose a shooter to 165 dB for 2msec, is equivalent to over 40 hours in a noisy workplace.ĭr. Louis, the damage caused by one shot from a. senior research scientist in charge of the NOISE LABORATORY at the Central Institute for the Deaf in St. Keep in mind that conversational speech is approximately 60-65 dB, and the threshold of pain is considered to be 140 dB.Īccording to Dr. Use this chart as a reference guide for promoting the need of using adequate hearing protection. With the introduction of MUZZLE BRAKES and PORTING, the risks of hearing loss dramatically increase. Download Gunfire Noise Level Flyer–PDF (154k).īelow we have listed critical data describing peak sound pressure levels produced by firearms used in shooting and hunting sports.Ī serious byproduct of this exposure is sensory-neural hearing loss, which cannot be restored to normal.
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