Double hearing protection is needed in work environments with noises that exceed 100 decibels on average over an eight-hour shift. Workers can wear ear plugs underneath their protective earmuffs to stay safe in these situations. They should also test the noise level regularly to find out if this equipment is necessary based on the exposure level.
Occupational hearing loss remains a persistent problem in work zones across the U.S. Many machines and industrial processes create loud noises that can put workers at risk of losing their hearing. According to the Occupational Safety and Health Administration (OSHA), 22 million workers are exposed to potentially damaging noise at work yearly.
When the eardrum is exposed to loud noises, it kills the nerve endings that allow the brain to process this information. Once the nerve endings die, a person may lose their ability to hear high-frequency noises. Other symptoms of hearing loss can include ringing in your ears, noises sounding more muffled, and difficulty following normal conversations. There is no cure for hearing loss and it cannot be corrected through surgery or medication, which is why it’s so important for workers and companies to reduce their risk by wearing the proper protective equipment.
Many workers exposed to loud noises use hearing protection, including ear plugs and earmuffs, to protect themselves at work, but one set of plugs might not be enough to prevent hearing loss in some situations. In this case, workers should use double hearing protection to insulate their ears from loud noises further.
What is Double Hearing Protection?
Double hearing protection is the use of two hearing protection devices at the same time. The easiest way to double up on hearing protection is to wear ear plugs underneath earmuffs. This limits the amount of sound going into the person’s ear, so they don’t have to rely on the plugs alone—Again, size can be an issue. The worker needs to ensure that they do not interfere with the fit of the earmuffs and vice versa. The plugs must be properly inserted into the ear canal to block the incoming noise. The earmuffs must also create a perfect seal around the person’s ears. Wearing the muffs shouldn’t cause the plugs to shift out of place or force them to press against their ears, which can be painful. Some devices are disposable, meaning they will need to be thrown away at the end of each shift. Workers should use uncorded ear plugs when wearing earmuffs instead of banded or corded plugs to wear both items at once.
When is Double Hearing Protection Required?
OSHA requires workers to wear hearing protection when exposed to noises at or above 85 decibels averaged over eight working hours or an eight-hour time-working average (TWA). This is considered the threshold for hearing damage. Once noise levels surpass the eight-hour TWA, hearing damage is likely to occur.
But double hearing protection is required when workers are exposed to 100 decibels or more over an eight-hour TWA, according to the National Institute for Occupational Safety and Health (NIOSH). The Mine Safety & Health Administration (MSHA) also requires double hearing protection when noises reach 105 decibels or more for an eight-hour TWA.
How to Choose Double Hearing Protection
Workers and employers can start by measuring the noise level in the workplace using a sound meter. If the company isn’t sure if hearing protection is required, a good rule of thumb is that if workers cannot hear each other from three feet away using a normal speaking voice, the sound levels are likely above 85 decibels. If the TWA noise level exceeds the 100 dba threshold, additional sound protection is needed regardless of the task at hand.
Double hearing protection reduces the overall sound exposure level by adding another layer of insulation. Every hearing protection device has a Noise Reduction Rating (NRR) that shows how much the device will reduce the noise exposure level. For example, if the environment comes with a noise level rating of 100 decibels over the eight-hour period and the device comes with an NRR of 30 decibels, the worker would only be exposed to 70 decibels when the device is in place.
When selecting double hearing protection, workers can add 5 decibels to the NRR for the device with the higher noise reduction rating. For example, if a worker is wearing a set of ear plugs with a 25-decibel noise reduction rating and earmuffs with a 30-decibel noise reduction rating, they would add 5 decibels to the earmuffs for a combined noise reduction rating of 35 decibels.
A common choice among employers is to have workers wear earmuffs with disposable ear plugs that can be added in loud settings.
If employers believe there is a chance their workers will need double hearing protection, they will need to adjust their hearing conservation program accordingly. This can be done by testing the noise level regularly and ensuring enough hearing protection devices are available to staff so that each person can wear two devices at once. The equipment should also be cleaned and maintained before and after every use to prevent the spread of germs and bacteria. Consider hearing screening tests for new employees. This can serve as a defensive way to prevent later claims of work-induced hearing loss or tinnitus.
Employers should only have their employees wear two hearing protection devices at the same time when it is required; otherwise, the equipment might interfere with their ability to hear important sounds and warnings on the job. If double hearing protection is used, workers should be able to rely on visual alerts and warning systems in case of an emergency. These signs and warnings should stay in their line of sight, so they can respond accordingly without having to remove their ear plugs or muffs.
Workers must be trained on how to use this equipment and know when to use double hearing protection. Extra ear plugs should be easily accessible or kept on a worker’s person, so they can use them quickly on the job when loud noises occur. They should also be aware of warning signs of hearing loss, including hearing a ringing or humming in their ears.
Single hearing protection is not always enough to prevent long-term hearing loss. Workers should have access to additional hearing protection when sounds exceed the 100-decibel threshold over an eight-hour time-working average. Contact the professionals at PK Safety to learn more about our hearing protection devices.