This photo shows Theresa Schulz conducting an ear plug fit testing session. (Howard Leight by Honeywell/Honeywell Safety Products photo)

The Fit Testing Revolution

More and more studies are coming out that document the benefits of ear plug fit testing for industrial workers.

About 22 million U.S. workers are exposed to hazardous noise levels at work, and hearing loss is the second-most-common occupational illness in America, according to NIOSH and the U.S. Bureau of Labor Statistics. NIOSH considers it crucial to improve the performance of hearing protectors, noting in April 2013 that failure to properly fit and use hearing protectors may be the leading cause of work-related noise-induced hearing loss.

A new technology that won a top agency award that month is part of the fit testing revolution that could result solve this problem. NIOSH Director Dr. John Howard announced that an ear plug fit testing system developed by agency employees had won the Technology Category of 2013's Bullard-Sherwood Research-to-Practice Awards. The HPD Well-Fit™ system measures a plug’s performance within 4-7 minutes, using a computer, sound-isolating headphones, and an algorithm to calculate the worker's Personal Attenuation Rating. The employees who received the award--William J. Murphy, Ph.D., Mark R. Stephenson, Ph.D., David C. Byrne, M.S. CCC-A, and Christa L. Themann, M.S. CCC-A--discussed the system's usefulness in a NIOSH Science Blog post one month later, writing that the speed of the test "makes it feasible to re-train and re-test the worker until mastery in fitting the protector has been achieved."

Jérémie Voix, Ph.D., an associate professor in the engineering department of the University of Quebec, in Montreal, has been involved in hearing protection research for the past 14 years, including working with Sonomax Technologies Inc., a company based in Montreal that pioneered the on-site, custom-fitted hearing protection category. "We were convinced that we could really prevent noise-induced hearing loss by properly fitting and protecting workers with good products, that would be custom products--custom molded to their ears," he explained.

Voix devoted his Ph.D. research to fit testing, which involves measuring the attenuation experienced in the field by someone wearing a custom-fitted ear plug. Being able to pinpoint quickly how much attenuation a wearer obtained from a given plug allows the attenuation to be adjusted, or tuned, so the individual is fully protected from dangerous noises levels but can hear equipment warning signals, for example.

"That was really new for the field. In seven seconds, you can see whether someone was properly fitting an ear plug, and maybe he hadn't for the last 20 years. Realizing that in just seven seconds was something that was a real breakthrough in this domain," Voix said during a March 2014 interview.

Now offered by several companies, this type of fit testing in recent years has revolutionized this PPE category. "What was amazing for me, because I really was at the heart of those developments--now it becomes really the trend. It's granted that everybody has to fit test hearing protection devices. I remember the first time I pitched the idea, the pushback was, 'Well, Jérémie, we don't have 10 seconds to test people.' Nowadays, all of the Fortune 500s that do buy hearing protection devices and ear plugs would require that the manufacturer have the ability to test for each worker the exact attenuation that could be documented, and trained, and so on."

A large percentage of the biggest plants in North America are aware of the availability of fit testing, he said, and the adoption curve for it looks very similar to the way employers and safety managers accepted and implemented individual fit testing of most respiratory protection devices.

Fit Testing's Benefits
More and more studies are coming out that document the value of ear plug fit testing for industrial workers, Voix said. "They [employers] realize that a lot of workers did not necessarily pick the best products for their ears," he said. "They just picked the product that was closest to the door and used it for 10 years and did not pay attention that the next one might actually be better for their morphology and their ear canal shape."

Voix agreed that workers who have been fit tested can be trained better to fit ear plugs properly, and he said seeing the attenuation data for themselves empowers and motivates workers to take ownership of their own hearing protection.

"That was so important because personal protection equipment really is personal. And if you don't have that direct connection with them, and it's just someone putting it in for them--now it becomes yours and you know how to fit it in," he added.

The OSHA/NIOSH/National Hearing Conservation Association alliance produced a Best Practice Bulletin1 about fit testing in August 2008. It listed these seven benefits from using it:

"1. Can be a valuable training tool. OSHA's Hearing Conservation standard requires employers to train employees in the use and care of hearing protectors (29 CFR 1910.95(i)(4)) and requires employers to ensure proper initial fitting and supervise the correct use (29 CFR 1910.95 (i)(5)).

2. Can be used as a train-the-trainer tool to teach others how to train employees.

3. Can assist with the OSHA required audiometric testing follow-up procedures.

a) Audiometric test follow-up procedures require that when the evaluation of an audiogram indicates an STS, employees already wearing hearing protectors must be refitted and retrained in their use and provided with hearing protectors offering greater attenuation if necessary (29 CFR 1910.95 (g)(8)(ii)(B)) and b) Individual fit testing protocols will validate the amount of attenuation afforded by the individual user's hearing protector and will enable the employer to better fulfill this requirement to provide a hearing protector with greater attenuation if necessary.

4. Can provide useful documentation regarding hearing protector adequacy and training. The software provides a written record of the attenuation achieved for the given hearing protector.

5. Can be used as a tool to assess the overall effectiveness of an employer's hearing conservation program.

6. Can enable the hearing conservationist 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.

7. Can aid in the selection of appropriate hearing protection for new hires. A variety of protectors can be tested, and the appropriate model can be selected for best protection."

EPA Rulemaking At a Standstill
OSHA requires that employees be protected from excessive noise through measures that follow the standard hierarchy of controls. However, the regulation that requires ear plugs to be tested and assigned a Noise Reduction Rating (NRR) is an EPA regulation, 40 CFR Part 211, Subpart B. Hearing protection professionals have known for years that NRRs based on laboratory tests differ widely from attenuation actually achieved in the field, and so these professionals have been keenly interested in testing that produces more realistic values. They also hoped that EPA would succeed in revising Subpart B, as the agency proposed in August 2009.

EPA proposed2 to change the packaging's label to display the NRR as a range of values that "indicate the lesser and greater levels of protection that a user can achieve when used according to manufacturer instructions." The revised standard would allow a new generation of significantly improved HPDs, including custom molded plugs and active noise reduction designs, the agency stated.

The revision also would have required recurring testing, at three- or five-year intervals, during the life of a product.

Five years later, the rulemaking is at a standstill. "You know, I've been on all those working groups and standards committees for the last five years. . . . And now they believe it will not actually happen," Voix said, adding that he understands no one at EPA is even assigned to the noise issue at this time.

That leaves the unrealistic NRRs in place, so a legislative fix to the problem is being attempted to remove the issue from EPA's purview entirely, Voix said.


This article originally appeared in the May 2014 issue of Occupational Health & Safety.

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