Did you know that 22 million workers are exposed to potentially damaging workplace noise every year? In fact, according to the National Institute for Occupational Safety and Health (NIOSH), hearing loss is one of the most common work-related illnesses.
The Effects of Hearing Loss
Some hearing loss is temporary and only results in short-term ringing or discomfort. But hearing loss can also be permanent. Exposure to high levels of noise will more commonly result in permanent hearing loss.
Hearing loss is a significant health issue, and also can be quite emotional for the employee. Neither surgery nor hearing aids can reverse the effects of noise-induced hearing loss.
The effects are detrimental not only to the employee, but also to the workplace. OSHA estimates that $242 million is spent annually on workers compensation for hearing loss claims.
Preventing Hearing Loss
- Using tools and machinery that produce less noise
- Enclosing the noise source or installing walls and curtains to contain noise
Examples of administrative controls include:
- Limiting the amount of time workers spend in noisy areas
- Rotating workers throughout the day so no one is constantly exposed
- Keeping workers a specified distance away from the noise source
When these types of controls are not feasible or sufficient, workers must wear adequate hearing protection devices, such as earplugs.
A Primer on Earplugs
Earplugs and earmuffs are used to physically block sound waves from hitting the eardrum. As long as they’re used properly, earplugs can go a long way in protecting workers from hearing loss.
The OSHA standard requires the use of earplugs when workers are exposed to noises of 90 decibels, A-weighted (dBA) or higher for an 8-hour time weighted average (TWA). The NIOSH recommendation is a bit stricter, and suggests hearing protection for noise levels of 85 dBA or higher.
So how do you know if the earplugs are bringing noise levels below that threshold?
Manufacturers provide a Noise Reduction Rating (NRR) with all of their earplugs. The higher the rating, the better the protection.
The Noise Reduction Rating
The Noise Reduction Rating specifies the level of protection earplugs will provide from noise hazards. However, many people don’t understand how to properly calculate the NRR for their workplace.
That's because the NRR listed on the package is not the actual amount of protection your workers will receive from wearing the earplugs.
Instead, you must calculate the real NRR by doing a little bit of math.
OSHA lists several ways you can calculate the NRR. But the quickest and easiest method is shown here:
Estimated Exposure (dBA) = TWA (dBA) - [(NRR - 7) x 50%]
Let’s look at an example. Say you work in an environment with an exposure level of 100 decibels. And you use an earplug with an NRR of 30. Most people would think that wearing the earplugs in this environment would bring the noise level down to 70 decibels.
But using the calculation from above, we can see that the new decibel level is actually 88.5.
Estimated Exposure (dBA) = 100 - [(30 - 7) x 50%]
Estimated Exposure (dBA) = 88.5
So, why do you have to do all this math? What is the purpose of subtracting by seven and then dividing by two? OSHA strongly encourages employers to do this because it represents a more accurate NRR than what is typically achieved in laboratory testing. In other words, the NRR listed on the package isn't wrong; it just has to be adjusted for workplace conditions.
(To learn more, see Hearing Protection PPE: Beyond the Basics.)
The Different Kinds of Earplugs
There are many different kinds of earplugs for you to choose from. Here is a breakdown of the various shapes and styles.
Expandable Foam Plugs
Foam earplugs are made from expandable material that is designed to conform to the shape of the user’s ear. These earplugs typically provide the best combination of comfort and protection when worn properly.
Expandable foam plugs are disposable and should only be worn once.
The major disadvantage of using foam plugs is that they are associated with an increased risk of ear infections. Workers have to roll the plug with their fingers before inserting into their ears. If their hands are dirty or contaminated, it can can cause irritation or an infection.
Pre-Molded, Reusable Plugs
Pre-molded earplugs are most commonly made from silicone, plastic, or rubber. They are pre-formed and therefore do not expand like foam plugs do. And while they come in various sizes, it can take a lot of trial and error to figure out which size works best for each employee.
These earplugs can be washed and reused several times before they need to be replaced. There’s also less chance of infection, since the user does not have to touch the end that goes into their ear.
Most of these plugs will come with a small plastic case, so they’re convenient to store and carry around.
Canal Caps or “Bands”
Canal caps are convenient because the earplugs are situated on bands or straps that can be worn over the head, behind the neck, or under the chin. The earplug tips come in both the pre-molded and foam styles.
Workers can quickly insert these earplugs when entering areas with hazardous noise.
Custom Fit Earplugs
Another option is to purchase custom fit earplugs.
Moldable earplugs are made from a silicone putty, which is waterproof and resistant to melting in high temperatures. These disposable plugs come individually packaged. To use, the worker simple shapes a piece into a ball and pushes to fill the outer ear around the canal.
This style is less common in the workplace. They’re mostly used for sleeping and for protecting swimmers from getting water in their ears.
Some manufacturers offer a custom-fit option that is reusable. This is going to be more expensive up front, but they may last longer and they’ll provide excellent protection for your employees.
Earmuffs are an alternative option that some workers may prefer. They can either be attached to a hard hat, or can also be used as a stand-alone pair in areas where hard hats aren’t required.
Earmuffs have a rigid exterior with soft cushions on the inside that seal around the entire ear. They come in various styles, and some are more "low profile" than others. Earmuffs can also include electronic components for communication or blocking specific frequencies of noise.
How to Properly Insert Earplugs
You might think that inserting earplugs is easy, and that it shouldn’t require any extra training. But you’d be surprised how many people get it wrong. Below is an image taken from the NIOSH website that shows the proper way to insert and use protective earplugs.
(See Are You Wearing Your Earplugs Properly? It Might Be Destroying Your Hearing to learn more.)
Choosing the Right Pair of Earplugs
With so many different styles, how do you choose the right earplug? Much of it comes down to fit and comfort. But each employee might have their own preference. That’s why it’s important to have a few options on hand for workers to choose from.
Click here for more of our Hearing Protection content.