What is Noise Reduction Rating? Why You Should Care

If you are around loud noise and wear hearing protection headsets, earplugs, or muffs, you might have heard the term noise reduction rating (NRR).

Noise reduction rating, commonly labeled NRR, is a unit of measurement that determines how effective a hearing protection device is at reducing sound exposure.

The higher the NRR rating on a hearing protector, the better is it at reducing noise. Sound is measured in decibels (dB). The higher the decibel level the louder the noise is. Noise reduction ratings show you how much the device will decrease the decibel level.

How is Noise Reduction Rating Calculated?

The NRR rating is determined by various tests in laboratories. Hearing protection devices are to be tested and approved by both the Occupational Safety & Health Administration (OSHA) and the American National Standards (ANSI). These tests determine what the approximate rating is, give or take a 50% correction factor per OSHA’s recommendations.

To calculate the actual number of decibels the hearing protector will reduce, we’ll use a simple formula.

(NRR-Rating – 7)/2

First, take the NRR rating number and subtract 7. Then take that number and divide by 2.

Let’s do an example together. I find that my headset has an NRR of 23. Using the equation above, I subtract 7 from the NRR rating to get 16. Now I’ll divide that by 2 to get my final answer of 8.

This shows that my headset will reduce the sound exposure by 8 decibels.

Let’s put that in context. 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.

Wearing hearing protection is always recommended if you are around noise louder than 90 decibels.

You can increase your noise reduction rating with double hearing protection, like wearing earplugs with a headset. To calculate your new NRR rating, you won’t be adding the two NRRs together. Instead, you’ll add 5 to whichever device has the highest NRR rating.

For example, if you wear earplugs with an NRR of 28 and a headset with an NRR of 21, we’ll add 5 to the earplugs giving us a new NRR of 33 dB.

Using the equation above, if we wore just the headset alone, it would decrease our sound exposure by 7 dB. By doubling up, we’re now decreasing our sound exposure by 13 dB.

What is a Good Noise Reduction Rating?

While every noise reduction rating is good since it helps reduce the sound exposure around you, there is no “best” rating. As mentioned before, the higher the noise reduction rating, the better it is at reducing the decibel level. The NRR rating you want should depend on the kind of environment you’re in. If you’re around a shooting range, firearms give off a dB level of 165 (higher than a jet). In this case, you’ll want to find the highest NRR rating you can to protect your hearing.

If you want the best protection, compare your device's NRR ratings and go with the one with the highest rating.

NRR Ratings vary among the type of devices. For instance, the highest NRR rating on earplugs is 33 while the highest NRR rating for earmuffs is 31.

SUGGESTED READ: Hearing Protection Earmuffs vs Earplugs

Decibel Level Chart

You might not understand just how loud your environment is. As mentioned before, it's recommended to wear hearing protection in any environment where it's louder than 90 decibels. Below is the decibel level chart to show you just how loud the world around you is.

Why You Should Care

You should care about the noise reduction rating of your devices to know just how protected you are against loud noise. Once your hearing is gone, it’s not coming back.

According to the National Institute for Occupational Safety & Health, over 22 million workers are exposed to hazardous noise levels at work each year in the United States.

Moreover, hearing loss disability results in an estimated $242,000,000 in workers’ compensation payments annually. Hearing damage is an invisible disability that not only negatively impacts an individual’s health and well-being, but it creates an occupational safety risk for everybody.

Tips for Protecting Your Hearing

In addition to wearing proper hearing protection, you should be following other tips for protecting your hearing too.

• Take breaks and limit the amount of time without proper hearing protection
• Move away from loud noise every 15 minutes and give your hearing an applicable amount of time to recover before exposure again.
• Wear earplugs and headsets properly

Wearing your earplugs and headsets the correct way ensures you are getting the most protection to prevent hearing loss.

Who Should Be Wearing Hearing Protection?

While hearing protection is extremely important for anyone, there are certain groups of people who should be wearing hearing protection while at work. If you are exposed to high levels of noise for an extended period and exposure over 90 decibels, you should always be protected. Some of these industries include,

1. Manufacturing
   It should come as no surprise that manufacturing floors ring with a constant combination of loud machinery, clanking metal, compressed air, and all the other sounds that go into the production of goods.
   
   Statistics show that 80% of manufacturing workers suffer from some level of hearing impairment, the majority occurring within the first decade of employment. The manufacturing industry has a high demand for hearing protection equipment.
   
   
2. Construction/Carpentry/Mining
   These three industries vary greatly; however, they all share the common thread of work-related hearing loss. The tools utilized here operate as high as 115 dB (well above the recommended limit of 85 dB), and lack of oversight along with seasonal employment has made it difficult to fight hearing damage.
   
   For workers in these industries, we recommend that hearing protection be implemented at an individual level to remain protected.
   
   
3. Military
   The levels of hearing impairment among military veterans have reached that of an epidemic. Although some soldiers might only deploy for a short period, the gunfire, explosions, and aircraft engines regularly associated with warfare can leave a lasting impact on one’s quality of life.
   
   The Hearing Health Foundation conducted a study showing that over 60% of returning combat troops from Iraq & Afghanistan suffered from noise-induced hearing loss – the most common service-related disability. As a result, the Department of Defense has initiated the development and implementation of more advanced hearing equipment to protect those serving our country.
   
   
4. Agriculture
   Over a third of farmers in the United States have hearing loss. The loud sounds of combines, tractors, livestock and other equipment are experienced from a young age, continuing daily if they work their farm.
   
   Federal agencies and local groups have taken steps to educate the younger generation on the importance of hearing protection as well as a push for manufacturers to improve noise reduction, however, the issue remains to be fully addressed.
   
   
5. Concerts
   A rock concerts decibel level ranges from 90 to 120 dB. After a concert has ended, many people report experiencing temporary music-induced hearing loss. While it's not generally permanant, loud noise over time can permanently damage your hearing so it's important to wear hearing protection such as earplugs.

The industries above are just to name a few, other industries that need to be wearing proper hearing protection are,

• Aircraft Maintenance Workers
• Musicians/ Entertainment
• Factory engineers
• Sport game officials