Double hearing protection
What is double hearing protection, and when is it needed?
Responding is Nancy Sabin, product manager for above-the-neck products, Protective Industrial Products Inc., Latham, NY.
To understand what double hearing protection is, let’s start by reviewing why it’s needed. OSHA’s occupational noise exposure standards are intended to protect general industry workers from experiencing hearing damage by regulating the amount of noise they’re exposed to on the job. This requires the implementation of a hearing conservation program and having administrative controls in place. For general industry applications such as utility, manufacturing and service-sector work, adhering to the OSHA standards can typically be achieved by using a single hearing protection device – earmuffs or earplugs. This is because the attenuation of a singular hearing protection device is enough to ensure adequate protection for the wearer.
Double protection is necessary when the attenuation of a singular hearing protection device is not enough to ensure adequate protection for the wearer. Let’s review a few situations in which a single hearing device would be insufficient. According to NIOSH, any worker whose 8-hour time-weighted average exposure exceeds 100 dBA should wear double hearing protection. Double hearing protection is also required in mining operations governed by the Mine Safety and Health Administration for noise exposures in excess of 105 dBA for an 8-hour time-weighted average.
Now that we have identified a couple of situations that require the use of double hearing protection, let’s expand on what double hearing protection is. It’s simpler than you might think: Double hearing protection occurs when two hearing protection devices are used at the same time. The dual – or “double protection” – factor is most commonly achieved by wearing earmuffs and earplugs. A key element of ensuring you’re achieving the highest decibel protection when wearing earplugs as a part of your dual hearing protection is understanding the impact their fit has on effectiveness: To receive the highest protection, the earplug must be worn properly. If it’s not, the added protection from wearing two devices may not be sufficient.
Wondering how the efficiency of double protection translates to higher decibel levels? All it takes is a simple calculation to determine the level your double hearing protection is providing: Add 5 dBA to the highest noise reduction rating of the higher-rated hearing device. For example, if you’re using an earplug with a 30 NRR and an earmuff with a 26 NRR, you would add 5 dB to the 30 NRR for the earplug. Your protection level would then increase to 35 dB, assuming the earplug is worn properly. This simplified method of calculating double protection dBA is based on OSHA recommendations.
One downside to wearing double protection is that it may put the worker in harm’s way should he or she be unable to hear warning sounds in the surrounding area. For this reason, double hearing protection should be carefully considered for certain worksites.
The best practice is to use the right product to attain the comfort level and fit you need to be safe on the job without compromising your ability to be aware of your surroundings.
Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.