The Value of Ear Plug Fit Testing

Only one factor was found to be a consistent predictor of good ear plug fit: one-on-one training.

• By Renee S. Bessette
• Jun 01, 2011

Although prevention has been the mantra in occupational hearing conservation programs over the years, the hoped-for results have not been realized. Despite years of regulation, hours of training, and billions of dispensed ear plugs, the incidence of noise-induced hearing loss (NIHL) in the workplace continues to rise worldwide. In the United States, more than 22 million workers are exposed to hazardous noise on a daily basis, and 8 million suffer from NIHL.¹ In some noise-intense industries, the rates of hearing loss are tremendous. For example, 50 percent of carpenters and plumbers, and 90 percent of retiring coal mine industry workers have NIHL.²

Safety professionals have a universal challenge in protecting the hearing of their noise-exposed employees: How much protection do their employees actually achieve with their ear plugs?

As rating methods are based upon idealized laboratory conditions designed to test the capability of the hearing protector, published attenuation ratings such as the Noise Reduction Rating (NRR) have been criticized for being too generous in their estimation of noise blocking (attenuation). Studies indicate that while some workers in real-world work sites achieve the published attenuation on the package, many workers do not. This has led to a variety of inappropriate de-rating methods applied to hearing protection around the world and has contributed to much confusion in knowing how to accurately estimate a hearing protector's attenuation in real-world use.

Thus, determining whether workers have optimal real-world attenuation for their noise environment is critical to the success of an occupational hearing conservation program.

Ear Plug Fit Testing Technology
Through new ear plug fit testing technologies, safety managers and workers now have an accurate, real-world picture of hearing protector effectiveness, providing a starting benchmark on which to build their hearing conservation practices. First and perhaps foremost, fit testing provides a formal metric from which one can determine whether employees are receiving optimal protection for their noise environment, require additional training on how to fit their ear plugs, or need to try a different model.

Ear plug fit testing benefits safety managers and employees alike. For the safety manager, it fulfills regulatory requirements for training with documented results. For employees, it demonstrates the importance of proper protection in the workplace and helps them select and compare protectors to find the best choice for their ears and specific applications.

In a recent evaluation, a UK laboratory that performs technical studies and certifications on personal protective equipment for the European Community identified that an ear plug fit testing system "appeared to have the potential to aid correct fitting and selection of ear plugs.: Further, it validated that ear plug fit testing "data demonstrated that it would be a useful tool for ensuring Hearing Conservation within the workplace."³

Field Attenuation Study
The value of fit testing was evident in a field attenuation study conducted by the Howard Leight® Acoustical Laboratory on the performance of hearing protection devices. Conducted on more than 100 workers at eight different facilities, the study showed that one-third of workers achieved attenuation higher than the published attenuation for their ear plugs and another third achieved attenuation within 5 dB of the published rating. But the lowest one-third of workers had attenuation that was more than 5 dB below published attenuation.⁴

The study then interviewed the workers who obtained high attenuation values to determine the common factors that contribute to good ear plug fit and, hence, good attenuation in use. Only one factor was found to be a consistent predictor of good fit: one-on-one training. That is, the more often a worker had received individual training in the proper use of hearing protectors, the higher the probability of a good fit. The same was not true for group training, such as watching annual training videos or passing out brochures.

The importance of fit testing as a critical element of one-on-one employee training cannot be overstated. No generalized rating scheme for hearing protectors can be effective without knowing how much attenuation individual workers actually attain. If a safety manager were to supply ear plugs based on the assumption that all ear plugs achieve only half of their published attenuation in the field, then clearly two-thirds of the 100 workers in the study would be seriously overprotected, because they are achieving much higher protection than 50 percent. Fit testing of hearing protectors bridges the gap between the laboratory estimates of attenuation and the real-world attenuation achieved by workers as they normally wear their protectors.

Additionally, fit testing can be an invaluable tool in reducing compensation claims for noise-induced hearing loss at the workplace. Fit testing records can help document that effective steps were taken to select appropriate hearing protectors, train workers in their proper use, and to document a proper fit with a particular protector. This level of powerful documentation has been unavailable to hearing conservation programs in the past.

The Future of Hearing Loss Prevention
Ear plug fit testing is gaining greater adoption by hearing conservation experts and by industry as a key tool in hearing loss prevention.

In a Best Practice Bulletin issued by an alliance between the National Hearing Conservation Association (NHCA) and OSHA, ear plug fit testing was endorsed as a recommended best practice in reducing occupational hearing loss as well as a metric to assess a hearing conservation program's overall effectiveness.⁵ The bulletin also cited fit testing as a way to "match the employee's hearing protector attenuation to his/her noise exposure level. This may be particularly useful in hearing critical jobs or for those with hearing impairment."

At the 2011 NHCA conference, a full-day workshop spotlighted the available ear plug fit testing technologies and allowed attendees to try each system. Several platform presentations throughout the conference also identified the benefits of ear plug fit testing, emphasizing the benefits of selection of an appropriate hearing protector and one-on-one training for workers. Plus, the Safe-In-Sound Award, presented by NIOSH/NHCA for excellence in hearing loss prevention, was presented to Shaw Industries. In presenting the award, the award recognized Shaw's implementation of ear plug fit testing as a critical success factor in its hearing conservation program.⁶

In addition, an ANSI working group has been assembled to evaluate and create a new standard for the performance criteria of hearing protector fit testing systems.⁷

Conclusion
While many occupational hearing conservation programs have the best intentions to ensure that workers are using hearing protectors, the ultimate goal is to ensure that workers wear them properly 100 percent of the time when exposed to hazardous noise. Ear plug fit testing technology better enables and empowers workers to achieve this goal to facilitate a life of healthy hearing.

References
1. NIOSH Pub. No. 2001-103
2. NIOSH Pub. No. 2001-103
3. INSPEC Report www.hearforever.org/veriproinspecreport
4. Witt, Brad. "Fit Testing of Hearing Protectors." Occupational Health & Safety, 2 October 2007. http://ohsonline.com/articles/2007/10/fit-testing-of-hearing-protectors.aspx
5. OSHA/NHCA Alliance. "Best Practices Bulletin: Hearing Protection — Emerging Trends: Individual Fit Testing." http://nhca.affiniscape.com/associations/10915/files/AllianceRecommendationForFitTesting_Final.pdf
6. http://www.cdc.gov/niosh/updates/upd-02-24-11.html
7. ANSI S12.71-200X standard, Performance Criteria and Uncertainty Determination for Individual Hearing Protector Fit Testing Systems

This article originally appeared in the June 2011 issue of Occupational Health & Safety.