As earplugs are the cheapest form of ear protection (among other benefits) they tend to be the most popular choice for people looking to protect their hearing from excessive noise.
To understand how earplugs work, we need to take a look at how hearing works and then what causes hearing loss.
How Hearing Works
When you hear something, it is the end result of sound frequencies traveling the ear canal to your eardrum. These frequencies are then sent to the inner ear where they vibrate tiny hair cells which turn the vibrations into electrical signals which are then sent to your brain. Once your brain receives these signals, they are interpreted as sound.
How Hearing Loss Happens
Now that we understand how you hear sounds, we can take a look at how hearing loss happens. When you’re in an environment where the noise level is 85 dB or above, damage to your hearing occurs. Depending on how loud the noise level is, this damage can be instant or can happen over a series of hours.
Hearing damage stems from loud noises damaging the tiny hairs in your inner ear – which are extremely sensitive and are responsible for turning vibrations into sound. These hair cells do not regenerate so when they get damaged from loud noises, your hearing is permanently damaged.
How do Earplugs Work
With that baseline knowledge of hearing and hearing damage, we can look into how earplugs prevent hearing damage.
Earplugs work by expanding in your ear to completely seal off your ear canal from damaging noises. Since you can still hear, some of the frequencies still enter your ear but it is a significantly lower the sound frequencies to a level that will not damage your hearing.
While earplugs can be very effective at preventing hearing loss, improper use can significantly reduce the effectiveness of earplugs. Ensure that your earplugs properly fit and are used correctly in order to make sure that you are getting the full benefits the ear protection.
It is also important to note that not all earplugs are the same – different earplugs have different Noise Reduction Ratings (NRR) and provide different levels of protection. To understand how effective your earplugs are and whether you still risk hearing protection, you will need to calculate the effective decibel level. We can use the following formula to do this:
Effective decibel level = (Actual decibel level) – ((NRR – 7)/2)
This means that if your earplugs have a NRR of 33 dB and the noise level is 110 dB, when you use your earplugs, you would effectively be in an environment with a Noise level of
(110) – ((33-7)/2) => 110 – 13 = 97