What you need to know about NRR before selecting a hearing protection device.

What you need to know about NRR before selecting a hearing protection device.
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What you need to know about NRR before selecting a hearing protection device.

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Hearing protection is necessary for those living or working in a noisy environment such as construction sites, airports, factories, or even entertainment venues. According to the Occupational Safety and Health Administration, anyone exposed to noise equal to or above 85 decibels regularly requires wearing hearing protection devices.

This is important because not wearing hearing protection can lead to permanent hearing loss, and if care is not taken from the get-go, it can be hard to prevent. However, there are a few things to know before you set out to select the right hearing protection device for yourself, and NRR is one of them.

What is NRR?

NRR is an abbreviation of Noise Reduction Rating, a unit of measurement used to determine how effective a hearing protection device is in reducing exposure to noise within a working environment. In other words, it tells the extent to which hearing protection devices may reduce the overall noise you are exposed to.

Therefore, hearing protectors need to pass the American National Standards (ANSI) in line with Occupational Safety and Health Administration (OSHA) to be declared effective for commercial use. However, it is important to keep in mind that any hearing protector's NRR is a laboratory tested figure. So the actual noise reduction provided by any such device may be lower than what their Noise Reduction Rating indicates.

How does it Work?

The rule of thumb is that the higher the Noise Reduction Rating (NRR) of a device, the better it is. In fact, the highest NRR hearing protection devices are considered the best. However, as discussed above, these ratings are not as simple to decipher. For example, if you are on a construction site that has a noise exposure of 100 dB and you are wearing hearing protection headphones with an NRR of 40 dB, it does not mean that you are now exposed to 60 dB of noise.

The actual reduction in the level of noise will always be less than what the NRR states. So, to calculate the real decibel deduction provided by the hearing protector, you will have to apply the following formula:

(NRR – 7)/ 2 = Actual Decibel Deduction

Hence, following the above-stated example, you subtract 7 from 40 (which is the NRR of protective headphones) and divide the resulting number (33) by 2. So, the actual noise reduction provided by the headphones is 16.5 dB, and you are exposed to 83.5 dB of noise after wearing the hearing protection headphones.

Do not let this information undermine the importance of wearing hearing protection because it is important to remember that something is always better than nothing, and in this case, it is actually necessary. Moreover, to maximize noise reduction, wearing the hearing protection device properly is also crucial.

Wearing Dual Protection

Oftentimes, when people work in excessively noisy conditions, they tend to wear double protection. For example, someone may choose to wear earmuffs on top of hearing protection earplugs. In this case, the total decibel reduction will not come by adding the individual reduction of each protective device.

To determine the total actual decibel reduction provided by both, you add 5 decibels of protection to the device with the higher NRR.

So, for example, if the earmuffs have an NRR of 26 and the earplugs have an NRR of 32, wearing both together will provide a total noise reduction of 37 decibels.

What to Consider When Choosing Your Hearing Protection Device?

There are a couple of things to be cautious of when choosing your hearing protector. While NRR is one of the most important metrics to judge your potential protection device against, it is not the only thing to consider. In fact, the device which is right for someone else may not be the best for you.

Following are a few tips to help you understand how NRR should be used in the selection process and what are other factors to consider:

   1. Select the right NRR

Depending on your budget and the intensity of noise, the right hearing protection device for you can be different from that of someone else's. While 'the higher the NRR, the better the device' notion holds true, you may not require a hearing protector with a very high NRR if you are exposed to moderate levels of noise.

   2. Choose the right fit

The utility of your hearing protection device will be limited if it does not fit your ears perfectly, no matter how high its NRR is. For example, large ear defenders or headphones may appear to be an attractive option, but if they are loose on your ears, they may slip routinely, causing external noise to damage your ears.

   3. Select the right type

Just like the optimal NRR for your hearing protection device may vary; similarly, the right type of hearing protector can differ according to your workplace. There are a number of options available in the market, such as earmuffs, earplugs etc., with further variations among them. You should make your decision based on the exposure of noise level, your own convenience, and your audiologist's advice.

If you are present in a setting that exposes you to high noise levels, you must consider wearing hearing protection. By taking preventative measures from the beginning, you can retain your hearing function; avoid damaged hearing or even just the risk of developing noise-induced, permanent hearing loss.

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