There are times in our lives when we know it’s going to be loud — really loud. It may be at work. It may be on vacation. It can happen at home. This knowledge gives us the opportunity to plan ahead. We can protect ourselves from permanent hearing loss by taking precautions.
You may be asking though: Are earplugs enough? Do you need more protection? Or is there a point at which the added hearing protection is negligible?
Playing It Safe with Earplugs & Muffs
If you work in a noisy facility, you’re rarely exposed to ear-damaging sound regularly. There are usually specific rooms that are louder than others, or events that can cause the noise level to increase for a short time. A jackhammer, bead blaster or arc welder would make this level of noise. In these cases, noise can exceed 100 decibels (dB).
OSHA (Occupational Safety and Health) has rules in place to protect workers in this setting. A person can only be exposed to 90 dB for 8 hours. For every 5 dB, the sound goes up, the time allowed in that space gets cut in half. Employers must test the noise levels to be confident they’re compliant.
MSHA (Mine Safety and Health Administration) requires that employees use dual protection when exposed to 105 dB for greater than 8 hours.
Though these rules do protect American workers, they still permit exposure to damaging noise levels. Damage begins at just 85 dB. Many employees are in job roles where they experience this level of noise, and their employer should provide extra protection with earplugs or earmuffs or both.
How Dual Protection Impacts Employee Overall Safety
Balancing hearing protection and overall safety is paramount.
There is also concern that dual protection may increase accident risk. This fear is a common concern among pilots, police, and soldiers but can be equally troubling for those in a construction or manufacturing setting.
Hearing people wearing double protection may experience:
- Tuning out — A state in which the mind drifts from what they’re doing because their hearing isn’t engaged
- Relaxation — Being overly relaxed in some work environments can be dangerous.
- Hyper-Awareness — When we lose a sense, even temporarily, this can lead over-compensation by the other senses. Some people experience dizziness and exhaustion as a result.
- Hyper-Alertness — Loss of a sense can lead to the odd or impulsive reaction as the person is on constant high alert. This alertness can be channeled into an asset or it can become a liability.
- Falling asleep — For a hearing person, not hearing can cause drowsiness. The person could accidentally fall asleep if they’re not moving.
Employers must balance these risks with hearing protection. They can do this by providing training for those working in a soundless environment. They can additionally put visual cues and communication methods in place to help their employees stay safe. Finally, they can provide training on how to wear dual protection. Misuse these devices even over a short period of time can lead to permanent hearing loss.
Because an employer must weigh the risks versus the benefits, there are times when dual protection would be overkill. Because of this, OSHA doesn’t mandate dual protection.
Does Doubling Up Mean Double Protection?
Earplugs plus Earmuffs together do provide more protection than one or the other alone. But is it double? In other words, do you get the full protection of the earplugs plus the full protection of the earmuffs?
You’ve probably heard the saying that “sometimes the total is greater than the sum its parts.” This is not the case with dual protection.
Because of the conduction of sound through the bones, some sound bypasses the safeguards, making them less effective than they would otherwise be.
The frequency of the sound impacts how well doubling up provides extra protection. At a frequency of 2000 Hz, for example, the added protection becomes negligible.
When to Consider Extra Protection
Ear protective devices receive an NRR rating. This means that they’ve been tested to withstand the number of decibels corresponding to their rating. A standard set of earplugs will be around 20 NRR (20 dB of protection).
If you have earplugs that protect you from 20 dB and hearing loss starts at 85 dB, you should be safe up to 105 dB (85+20). Protection goes down as frequency goes down so having more protection than seems called for is advisable in a low-frequency setting. You can purchase earplugs up to 36 NRR.
The highest level protection that you can get from muffs is 31 dB.
It’s estimated that 97% of industrial work environments do not exceed 100 dB. This means that in the fast majority of work environments one or the other will provide ample protection. In the other 3%, dual protection is advised. Certain construction and manufacturing jobs, as well as, mining, quarrying and air traffic control are among the occupations that need dual protection.
Dual protection may also be called for when:
- Riding a motorcycle — 100+ dB
- Flying in a plane — 120 dB (during take off)
- At a shooting range — 140 – 190 dB
- At a concert — 100 to 120 dB
Thunder can also pack a punch at 120 dB if it’s very close.
Get your hearing checked annually and discuss hearing loss prevention options with a hearing specialist to best assess your situation.