Hearing Protection Introduction

There are many situations in which hearing protection is useful, necessary, and required by OSHA. It is important to wear some form of hearing protection when in environments with high sound levels. We measure the level of sound in a logarithmic unit called a “decibel.” A jet engine produces sound at about 120-140 decibels, while a conversational volume is approximately 55 decibels. At higher intensity levels, sound can damage microscopic hair cells in the hearing organ, otherwise known as the cochlea. Once those hair cells in the cochlea are damaged, there is no way to repair them. 

Hearing aids are the treatment for hearing loss and while the technology is quite advanced, the amplification provided by hearing aids is not guaranteed to sound the same as natural hearing. While damaging those hair cells can cause hearing loss, it can also cause a condition called “tinnitus.” Tinnitus is more commonly known as “ringing in the ears.” Many people with hearing loss experience tinnitus, and it can also be a sign of hearing loss. The best thing you can do to protect your hearing is wear hearing protection, such as ear plugs or over-the-ear headphones. But the common question is: when is hearing protection required?

Understanding Sound and Hearing Damage

To understand when hearing protection may be required, we need to know how sound travels. Sound is transmitted as sound waves. Sound waves travel as vibrations through a medium (air, water, etc). The three main properties of a sound wave are frequency, amplitude, and wavelength. Frequency refers to the number of waves a sound produces per second.

Frequency is perceived as pitch. High frequencies are perceived as high pitch (treble), and low frequencies as low pitch (bass). The measurement for frequency is Hertz (Hz); the higher the number, the higher the pitch. Therefore, the more waves produced per second, the higher the frequency (pitch) of the sound produced. Amplitude refers to the intensity, or loudness, of the sound. In the waveform, the amplitude would be how tall each wave is. 

Loud sounds have high amplitudes, while quiet sounds have low amplitudes. The measurement for amplitude is decibels (dB). Wavelength refers to the length of one full wave. Longer wavelengths result in lower-pitch sounds, and shorter wavelengths result in higher-pitch sounds. Frequency and wavelength are inversely proportional, meaning waves with higher frequencies have shorter wavelengths and vice versa. Sound waves vibrate the particles in the medium they are traveling through, which then travels into your ear canal and causes your eardrum (or tympanic membrane) to vibrate. 

Three of the smallest bones in the human body are behind the tympanic membrane. They are called the malleus (hammer), incus (anvil), and stapes (stirrup). The stapes is the smallest of them all! The malleus is directly attached to the tympanic membrane. When vibration is sent through the ear canal, it moves the tympanic membrane, the malleus, the incus, and the stapes. They work as a chain to move those vibrations to an opening in the hearing organ (cochlea), called the oval window.

The movement of the stapes on the oval window causes the fluid inside the cochlea to ripple and send a traveling wave throughout the basilar membrane. There are hair cells on the basilar membrane that detect the wave. Hair cells near the wide, apical portion of the cochlea detect high-pitch sounds, while hair cells near the narrow base detect low-pitch sounds. 

When these hair cells are exposed to loud sounds, this can result in hearing loss. Louder sounds, such as gunshots or fireworks, take less time to cause hearing loss. Although, everyday sounds such as music or a hairdryer can still cause hearing loss over time. Noise-induced hearing loss is usually seen in the higher frequencies, notably at 4000 Hz. This means that the hair cells in the cochlea around the 4000 Hz place were damaged.

When Is Hearing Protection Required?

Time spent around loud noises should be limited because it takes less time for the hair cells to be damaged. The higher the decibel, the more damage it can do. Levels of about 110-120 dB can cause instant damage to your hearing. Jackhammers and jet engines are examples of sounds that are in this intensity range. After exposure to sounds at this intensity level, you may experience tinnitus and a drop in hearing. For some people, their hearing may return to where it was previously. But for others, the hearing loss may be permanent. When is hearing protection required? Definitely at these higher decibel levels. 

There are many sources of noise-induced hearing loss, a common one being occupational noise-induced hearing loss. Military, aircraft, and construction Jobs commonly come to mind when talking about noise exposure. Those occupations surround many impact noises, such as jackhammers, gunfire, and loud factory equipment. Impact noises aren’t the only source of noise-induced hearing loss, though. Dentists, for example, are at risk for hearing loss due to near-constant exposure to their dental drills, and coming back to our question: when is hearing protection required? Thankfully, OSHA has set standards in place when it comes to noise exposure.

When Is Hearing Protection Required
Image Credit: Decibel Pro App

OSHA stands for Occupational Safety and Health Administration. They are a federal agency that regulates workplace safety, and all industries in the United States must follow their regulations. When is hearing protection required? OSHA states that an average exposure of 90 dBA over 8 hours indicates the necessity of hearing protection. This standard has an exchange rate of 5 dBA. This means that every time the exposure time is cut in half, the intensity level increases by 5 dBA. For example, working for 4 hours with the noise level at 95 dBA, you should wear hearing protection. Hearing protection should still be utilized if you work for 2 hours with the noise level at 100 dBA.

Choosing the Right Hearing Protection

Work isn’t the only place where hearing protection should be worn. There are also plenty of recreational activities that expose individuals to harmful noise levels. Recreational shooting, sporting events, jet skiing, and concerts are all examples of recreational activities that may cause harm to your hearing. It is a common thought that earplugs will distort the music at a concert, but there are different options and filters that should alleviate that concern. Westone provides custom musician’s plugs for this kind of scenario. 

You can contact a local audiologist to make molds of your ear canals, and they will send them in to make the earplugs! For a cheaper option without needing to get ear molds, you can try the Experience by Loop earplugs. If you need to raise your voice to be heard above the noise, you may need to wear hearing protection. At the very least, keep some foam earplugs in your bag or car just in case you need them on the go! You can find these in most convenience stores (or on Amazon), from brands such as Mack’s or Hearos. 

There are also various sources of noise in your home. Vacuum cleaners, hair dryers, blenders, microwaves, washing machines/dryers, and television are all forms of noise exposure that can affect your hearing over time. With a hair dryer that is loud and close to your ears, it is recommended to wear hearing protection. Outside of the home, some noise sources are out of our control. Construction and traffic noise are both common annoyances in many communities. In some instances, hearing conservationists may visit the area and implement plans to reduce the amount of noise generated in the community. 

As for the types of hearing protection, there are three main options: earplugs, earmuffs, and custom hearing protection devices. Hearing protection devices are given a Noise Reduction Rating (NRR), which should be written on the device’s packaging. Higher NRRs mean more attenuation (decrease in sound), therefore, more protection from environmental noise. Although, NRR may not be 100% accurate. If the seal is interrupted in any way, that can affect the noise reduction. This can be due to being bumped around or wearing glasses underneath earmuffs.

Custom hearing protection should be the closest to their stated NRR, while earmuffs and earplugs will only provide a percentage of their stated NRR. Earmuffs are approximately 25% less effective than their NRR, and earplugs are approximately 50% less effective than their NRR. There are pros and cons to each type of hearing protection device. Foam earplugs are fairly affordable and can be bought at almost any grocery store or pharmacy.

But, they may not be comfortable for those with smaller ear canals. They also must be inserted correctly to provide the expected protection. Earmuffs can fit just about anyone because they are made to fit over the entire pinna. But, as stated earlier, the seal can be affected by glasses, sweat, or movement. Custom hearing protection should be comfortable and have a good seal because they are made with a mold of your ear canal. But, they are not as affordable as the other types of hearing protection. 

Different situations may call for different forms of hearing protection. Many custom hearing protection manufacturers make them for many different activities. Whether for swimming, sleeping, shooting, or music, they have an option for you. If you are going to be in a situation where there is a chance you will be moving a lot, earmuffs might not be the best choice. If there is a chance that earmuffs will get knocked off, earplugs would be the better option. For hunting, there are custom hearing protection options with active noise cancellation. These devices will provide more attenuation when they recognize impact noises, such as gunfire. 

 Proper Use and Maintenance of Hearing Protection

When Is Hearing Protection Required

If your chosen hearing protection device is an earplug, you must insert them correctly to get the necessary attenuation. First, roll the foam insert between your fingers and get it as small as possible. Then, use the opposite hand of the side you’ll be inserting the ear plug and pull up and back on your pinna. Lastly, insert the earplug and hold it in place with your finger for about 20-30 seconds until it is fully expanded. Go through the same process on the other side, and you have successfully inserted your foam earplugs!

As for earmuffs, they are fairly user-friendly. Pull the muffs apart, and place one of the cups over one ear and then adjust the second one over your other ear. Most earmuffs have an adjustable headband that you can use to fit them to each person. Cleaning your hearing protection devices is also pretty easy. Foam earplugs are usually one-time use, and should be thrown in the garbage after each use. Custom hearing protection can be cleaned with soap and water, and fully dried before insertion. Earmuffs can be wiped down with an alcohol pad.

Hearing Protection Takeaway

Hearing protection is pertinent when in environments with high noise levels. When is hearing protection required? According to OSHA, any time the noise level is above 90 dBA for 8 hours (taking into account that 5 dB exchange rate). Wearing hearing protection at work is important for many different occupations, especially those with loud equipment and other environmental noise. Work definitely isn’t the only place to wear hearing protection, though.

Any activities or environments that loud noise is expected, it is in the best interest of your cochlea to wear your hearing protection! Once you damage those hair cells, there is no way to revive their previous function. Hearing loss can lead to depression, loneliness, social withdrawal, and studies suggest there is a link between hearing loss and cognitive decline. 

If there is ever a situation in which you find yourself raising your voice to be heard over loud background noise, consider wearing your hearing protection. Earplugs are easy to carry in your purse, pocket, or backpack for convenience and unexpected situations. If you are a hunter, or recreational shooter, please keep your hearing health in mind and invest in a good pair of custom hearing protection devices. Your local audiologist can help you with choosing the right pair for your situation.

It is never too late to protect your hearing, even if there is already hearing loss present. If you already wear hearing aids, wearing them around any loud noises is never recommended. You should still be wearing hearing protection in the same circumstances as someone with normal hearing sensitivity. 

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In addition to being the Founder and Editor-in Chief at HearingPeople.com, Luis Zuluaga is the founder and CEO of Florida Hearing Institute, an innovative hearing health enterprise in South Florida, focused on bringing high-tech hearing devices at affordable prices to people with hearing loss. Before his latest hearing healthcare endeavors, Luis served as President and Chief Operating Officer of Zounds Hearing Inc., a US-based hearing aid manufacturer that introduced many technical innovations to the hearing aid market.

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