Conventional wisdom has always held that properly inserting an earplug—while requiring some technique — was essentially a no-brainer, according to Brad Witt, director of hearing conservation for Sperian Hearing Protection, LLC. For years, safety managers have offered hearing protection with the assumption that fitting it is intuitive and fairly self-explanatory, providing only generalized group instruction, at best. As a result of this simplistic, group training approach, said Witt, rates of noise-induced hearing loss and corresponding compensation claims continue to climb worldwide. In some industries, as many as half of all workers can expect to suffer significant degradation of their hearing during their working careers. And in some countries, noise-induced hearing loss accounts for more than half of all reported occupational disease.
“The reality is that group training is simply not effective in teaching workers how to properly insert hearing protectors,” said Witt. “The message simply does not get through. Yet the difference between a good and a bad fit can be as much as 30 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. According to Witt, these studies have spawned a variety of de-rating schemes for hearing protectors which are often misunderstood or misapplied, such as the 50% OSHA de-rating; or the NIOSH 75/50/30% de-rating for earmuffs, formable earplugs, and pre-molded earplugs respectively. The EPA is also expected to announce a proposed rating regulation soon, substituting an attenuation “Range” for the current single number NRR.
But while well intentioned, these efforts do not touch the core of the problem, says Witt. He cites other studies which show that a significant core of workers do achieve good attenuation. The difference? Individual, one-on-one training. In addition, new subjective fit testing systems now available make it easy to incorporate individual training into an ongoing hearing conservation program.
Field research conducted by Howard Leight 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, one-third of workers showed attenuation within 5 dB below the published NRR, and about 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 ten 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, says Witt, new fit testing systems are available which 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 or her a “spike” of frequency loss on their annual audiogram. With these new systems it is possible for workers to see exactly how much attenuation they are getting from their earplugs, and how much attenuation can be improved with proper fit.”
Some systems, like VeriPRO from Howard Leight, can use the worker’s own unmodified earplugs, and can be performed in virtually any setting. VeriPRO consists of software and an optimized headset, and utilizes 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 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.
“Fit testing systems like VeriPRO benefit both safety managers and employees alike,” said Witt. “For the safety manager, they fulfill OSHA’s requirements for training with documented results. For employees, VeriPRO demonstrates the need for hearing protection in the workplace, and the importance of proper fit; it makes the concept of attenuation very real. It also helps them select and compare protectors to find the best choice for their ears and specific noise levels or applications.”
Said Witt, “My prediction is that incorporating fit test systems into the annual hearing training and testing regimen will do more to stem the rising tide of noise-induced hearing loss rates than any laboratory rating or labeling of hearing protectors.”