So you want to protect your ears but don't know where to begin. How can you ensure that your hearing protection is enough for a sound?
First off, whatever hearing protection you use will have an NRR rating on the box. This is a "Noise Reduction Rating" and it approximates the amount of decibels that are taken off of a sound. An NRR rating label should look like this:
IMPORTANT NOTE: These NRR ratings require you to subtract 7dB from the score. This 7dB has to do with the physical sound pressure hitting the body that cannot be approximated in a lab. With the label above, you should expect consistent protection of 8dB, not 15.
The goal of hearing protection is to make the environmental noise safe for the amount of time you spend there. If you are working an 8-hour shift in an environment, the noise level should be 90dB or under. For every additional 3 decibels over 90dB, that safe time is cut in half.
Many hearing conservation products have variable levels or filters of attinuation, which means that you can protect yourself from different levels of sound. For example, Westone's TRU Hearing Protection line has filters with 16, 20 and 25 NRR.
Why wouldn't you just use the strongest hearing protection for all circumstances? Depending on what you're doing, you may not want to block that much sound out. Hunters needs to hear what is around them, but subdue the blast of the firearm. Musicians want to stay protected but hear the sounds they are making. People in industrial settings may need to communicate with co-workers but protect themselves from machine noise.
Let's do an example of a real-world hearing protection situation. Get out your math caps!
Let's say that you work at a shipyard that regularly has a machine running at 101dB. You work an 8-hour shift. You are trying to decide if an headset with a 21 NRR rating would be enough.
First subtract 7 from the NRR rating- leaving 14dB of real-world attenuation.
Next subtract that from the actual exposure. 101dB- 14dB= 87dB
This is under 90dB which means that it's a safe level of attenuation for that environment.
Last note on hearing protection:
Pay close attention to the method of insertion. All these products require a full sealing of the ear canal or their ratings are pointless. Generally, the whole product should be in the ear canal, and nothing should be sticking out. This issue is, honestly, bigger than the issue of supplying protection at all in modern times. If your job provides earplugs, please put them in correctly!!!