Choice or preference is not optional, however, for the required use of hearing protective devices, according to NIOSH regulations if noise levels exceed 85 dBA (time-weighted average of decibels over a period of eight hours). See NIOSH Criteria for a Recommended Standard: Occupational Noise Exposure
Which type of ear protection is chosen by workers will depend upon the protection required (NRR), fit, comfort and convenience of either ear muffs or ear plugs. Ear muffs, often referred to as headphones, sit on top of your head and cover the ears, sealing out excessive noise. Ear plugs are small devices inserted inside the ear canal.
What is NRR?
A hearing protection device’s ability to reduce noise is referred to as its “attenuation” – the difference between the hearing threshold when the subject is wearing hearing protection and that when he/she is not, as measured in a laboratory. The higher the hearing protection device’s noise reduction rating (NRR), the greater its attenuation.
Ear muffs provide more representative attenuation in laboratory results as compared to in the field because ear muffs are easier to wear.
Features to Look For in Ear Muffs
- Full-spectrum and low-frequency attenuation
- Extra wide, soft-sealing ear cushions for comfort
- Soft padded headband with low force
- Steel headband, which tolerates temperature extremes
- Push-to-listen button to hear communication for radio headset ear muffs.
Features to Look For in Ear Plugs
Ear plugs, on the other hand, are more difficult to insert correctly, and therefore their attenuation (noise reduction) may not be accurately reflected in lab results.
When Might You Combine Both Ear Muffs and Ear Plugs for hearing protection?
If noise exposure exceeds 100 dBA, the National Institute for Occupational Safety and Health (NIOSH) recommends wearing both ear muffs and ear plugs for extra hearing protection in cases of extreme noise such as power saws, pneumatic hammers and jet airplanes at takeoff.
However it is faulty thinking in reasoning that combining both earmuffs and earplugs will double the protection. Doubling up with ear muffs and ear plugs does not result in double the hearing protection – since the physical energy of noise doubles with every three decibels.
For example, if you have two running machines each producing 60 decibels of noise, the combined noise level will not be 120 decibels; rather it will be 63. Similarly, if you double up with ear muffs and ear plugs both rated at say, 28 decibels, you will gain only three decibels of protection, for an effective NRR of 31 dBA.
Of course, using soundproofing materials in industrial or commercial settings can help to alleviate the noise levels or control noise levels to an acceptable level. At All Safety Products, Inc., we carry a vast selection of hearing protection equipment and devices.