Hearing Protection Findings Stand Conventional Wisdom on Ear

Conventional wisdom has always held that properly inserting an earplug — while requiring some technique — was essentially a no-brainer. As a result, safety managers typically have offered hearing protection devices with the assumption that fitting them is intuitive and fairly self-explanatory, and have provided only generalized group instruction, at best.

But this group-training approach may be one of the reasons why rates of noise-induced hearing loss and corresponding compensation claims continue to climb worldwide.

The message simply does not get through. Yet the difference between a good earplug fit and a bad one can be as much as 30 decibels (dB) of attenuation.

For decades, studies in the workplace have shown real-world attenuation (noise blocking) of hearing protectors to be less than the published Noise Reduction Rating (NRR) for many workers. These studies have spawned a variety of de-rating schemes for hearing protectors, which are often misunderstood or misapplied.

While well intentioned, these efforts do not touch the core of the problem. More recent studies show that a significant core of workers does achieve good attenuation. What's the difference? The answer: Individual, one-on-one training. In addition, new subjective fit-testing systems make it easy to incorporate individual training into an ongoing Hearing Conservation Program (HCP).

Field research conducted by the Howard Leight Acoustic Lab on 100 workers using earplugs from a variety of manufacturers showed that one-third of the workers achieved attenuation slightly higher than the published NRR, another one-third showed attenuation within 5 dB below the published NRR, and the remaining one-third showed significantly lower attenuation.

Moreover, the more often a worker had received individual training in the proper use of hearing protectors, the more likely he or she was to achieve a good fit. The same cannot be said for group training. When measuring good attenuation in the field, it appeared to make no difference whether a worker had attended zero, five or 10 group training sessions in hearing protection.

Unfortunately, individual training has always been time consuming, and it has not always been possible to make workers understand their vulnerability. Now, newer fit-testing systems are available that can help on both counts. We have always known that one of the best ways to get a worker's attention is to show him/her a “spike” of frequency loss on the annual audiogram. With these new systems, a similar impact can be achieved by showing workers exactly how much attenuation they are getting from their earplugs, and how much they can improve attenuation with proper fit.

Some fit-testing systems, such as VeriPRO^™ from Howard Leight, can use the worker's own unmodified earplugs, and fit testing can be performed in virtually any setting. The system uses a three-part process to determine the effectiveness of an employee's earplug fit over a range of frequencies. The result, known as a Personal Attenuation Rating (PAR), identifies the actual protection an employee receives from his or her earplug in each ear. This procedure allows safety managers to determine if their employees are receiving optimal protection, require additional training on how to fit their earplugs, or need to try a different model.

ABOUT THE AUTHOR

Brad Witt is director, hearing conservation, for Sperian Hearing Protection, LLC, San Diego, Calif. In addition to hearing protection, the ISEA member company also makes eye, fall, hand, foot, head and respiratory protection, eyewash and shower equipment, instruments and respiratory protective escape devices. Reach Witt at 800-430-5490 or [email protected].