Have you ever been in a closed stadium when your favorite football team won a game? Do you ever have to work in an exceptionally noisy setting? Are you familiar with the “ear-ringing” that is commonly experienced after attending loud concerts? Single hearing protection isn’t always enough, and that’s where double hearing protection comes in.
What is the effect of double hearing protection? Double hearing protection combines the hearing protection capabilities of earplugs and earmuffs and results in around 5dB of additional noise reduction. While this may seem ineffectual, it’s useful where single hearing protection is insufficient.
It is incredibly hazardous for the human ear to be exposed to excessive noise for an extended period. It can lead to a myriad of hearing issues, including hearing loss. This article will discuss the effects of double hearing protection, how it can benefit you, how you can figure out if you need double hearing protection, and more.
What is Double Hearing Protection, and Is It Effective?
Double hearing protection is attained by wearing both earmuffs and earplugs simultaneously. Both earmuffs and earplugs are known for their noise reduction capabilities, but since they may be ineffective used alone where excessive noise is concerned, a need to use both arises. But does using both at the same time make a significant difference?
The Occupational Safety and Health Administration (OSHA) states that determining the real value of any hearing protection device is challenging because of varying factors that affect the level of “real-life” noise. Luckily, since the lab-tested Noise Reduction Rating (NRR) of all hearing protection devices must be approved by the American National Standards Institute (ANSI), you can calculate the effectiveness of the devices.
Here is how you can figure out the NRR of your double hearing protection:
- Examine your earplugs and earmuffs to find which one has the highest NRR.
- Add 5dB to the one with the highest NRR.
Essentially, the effectiveness of your double hearing protection is determined by the NRR of the devices you are using. The higher the NRR of your devices, the better protection you will get.
The Effects of Double Hearing Protection
OSHA claims that lab-tested NRR can no way be assumed to be the same in normal conditions. So, using the NRR examples above, you will need to calculate the field noise reduction of both your single and double hearing protection to compare the results and prove the effectiveness of the latter. (Source: OSHA)
OSHA recommends that you apply 50% to the noise reduction rating to determine how effective a particular hearing protector can be. This is to create realistic expectations that can be found in the noisiest environments in the real world.
You’ll use an eight-hour time-weighted average sound level (TWA), which is common in working environments. It assumes the 8-hour typical working day and uses the average noise levels in each space. (Sources: Noisemeters Inc and OSHA)
To calculate the real-life effectiveness of single hearing protectors, you can use the following formula:
Estimated Exposure (dBA) = TWA (dBA) – [(NRR – 7) x 50%]
For 30dB earplugs in A-weighted sound levels of 100dBA, the calculation will look like this:
Estimated exposure = 100dBA – [(30dB-7) x 50%] = 88.5dBA
For earmuffs with the same NRR in the same environment, the calculation will look like this:
Estimated exposure = 100dBA – [(25dB-7) x 50%] = 91
When you combine both to figure out the real-life effectiveness of your double hearing protection, your calculations will look like this:
Estimated Exposure (dBA) = TWA (dBA) – {[(NRRh – 7) x 50%] + 5}
Estimated exposure = 100 – {[(30-7) x 50%] + 5 } = 83.5
While noise will still hurt your ears when using 30dB earplugs, adding 25dB earmuffs on top would get you to safe sound levels.
Although the 5dB increase from double hearing protection doesn’t seem to be much, it provides a significant sound attenuation because it remains constant. It may contribute to up to 85% of noise reduction, which is impressive. (Source: Sensear)
When is Double Protection Necessary?
According to the National Institute for Occupational Safety and Health (NIOSH), workers who are exposed to 8- hour TWA exceeding 100 dBA should wear double hearing protection. For example, mining workers are commonly exposed to excessively loud environments in 8-hour shifts. (Source: CDC)
Moreover, some people have hyperacusis, which makes their ears extremely sensitive. If you’re one of them, don’t settle on one pair of earmuffs or earplugs and instead use both for your safety.
Here’s when double protection becomes essential:
- You are near a place with sounds at or above 85 decibels for 8 hours or more. It’s about time, sound level, and distance. (Source: Noisy Planet)
- You’re hypersensitive to noise for any reason, such as hyperacusis or autism.
Double Hearing Protection Tips
If you cannot control excessive noise levels by reducing the volume, distancing yourself from the sound source, or reducing the time you spend in the noise, double hearing protection is the only option that remains. Here are some tips to help you implement it wisely:
Ensure a Snug Fit
Always ensure that your HPD fits perfectly. If not, you’ll feel discomfort, hurt yourself, or let in harmful noise. Look for a snug fit rather than a tight or loose fit. If your earplugs or earmuffs fit loosely, you’ll be underutilizing them.
Brad Witt, an audiologist from the Bacou Dalloz Hearing Safety Group, summarized this point by stating that the only way to benefit from double hearing protection is by attaining a proper fit, mainly the fit of the earplug. When a loosely fitted earplug is coupled with an earmuff, the hearing protection is limited to just the earmuff. (Source: Hearing Review)
Choose earplugs that seamlessly fit in most ears due to their flexible nature like these Eargasm Earplugs. Look for earmuffs with an adjustable headband design to ensure a snug fit that doesn’t compromise comfort. These Professional Safety Ear Muffs by Decibel Defense featuring 37dB NRR are one of the best HPDs online.
Think About Your Surroundings
Remember that, if you muffle and block most of the sounds around you, you might be in danger since you won’t hear any warning communication that might be directed your way. Even if it isn’t dangerous to your body, you might risk misunderstandings with your fellow workers and superiors.
You must find the right product to bring you the comfort you need to isolate noise but also maintain awareness of your surroundings. Therefore, check the typical noise levels in your workspace or any other place you want to use HPDs before purchasing your devices.
In your workstation, you only need to reduce sound levels to somewhere below 85 decibels according to OSHA’s guidelines. To determine your workspace noise levels, you can use a noise dosimeter and get an HPD that fits your needs. You can also use the noise dosimeter to gauge the noise levels of other settings.
Don’t Ignore Ear Health
While double hearing protection isn’t a must in many settings, don’t ignore it if you feel the noise is affecting you — even if it’s below 85 decibels.
Exposure to prolonged or excessive noise can lead to:
- Hearing loss
- Stress
- Tinnitus
- Cognitive impairment
- Cardiovascular diseases
- Poor concentration
- Communication difficulty
- Loss of productivity
- Fatigue due to lacking sleep
(Source: Australian Academy of Science)
Final Word
Double hearing protection adds five decibels of protection for your hearing. While this might not seem as much, it’s all the difference needed in boisterous places. A wise idea would be to use double hearing protection any time you feel that the noise level around you is bothering your ears, no matter what the decibel level is.
