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How Fit-Testing Earplugs Helped Boost Hearing Protection

In the oil and gas sector, where piercing noises are very common, nearly half of the workers suffer from noise-induced hearing loss (NIHL), according to WorkSafeBC organization.

Statistics show the percentage of workers with signs of hearing loss has increased by 12% over the last five years, from 33% in 2012 to 45% in 2017.

Meanwhile, Honeywell succeeded in substantially improving the hearing protection of Beerenberg workers, a major oil producer in Norway. Find out how Honeywell’s fit-testing training helped Beerenberg workers reduce their exposure to NIHL risks.

What is hearing protection fit testing?

Hearing protector fit-testing or field attenuation estimation system (FAES) is a method that determines how effective an earplug, or any hearing protection device is when worn correctly. Its effectiveness is measured as a personal attenuation rating (PAR) which is subtracted from the known noise exposure, estimating the total noise a person is exposed to when wearing the hearing protection device (HPD).

The National Hearing Conservation Association (NHCA) and The Occupational Safety and Health Administration (OSHA) have endorsed fit testing as a recommended best practice in reducing NIHL. 

OSHA hearing conservation programs are designed to prevent hearing loss due to an 8-hour time noise exposure equal or exceeding a sound level (TWA) of 85 decibels (dB).

Does wearing an earplug protect from NIHL?

“It has been repeatedly proven that simply wearing any earplug doesn’t necessarily protect from noise-induced hearing loss,” tells Kim Deason, PPE Solution Sales Manager at Honeywell Industrial Safety. 

“An earplug that is too small allows noise to flow right around it, so it offers little to no protection. Wearing one that is too large, pushing out when it recovers, isn’t doing a better job either. "

"Workers should also pay attention to choose the correct size. In the field, I have seen earplugs cut in half lengthwise or shortened, in hopes of a better fit. However, altering an earplug or any PPE for that matter is throwing away any guarantee that it will work the way it was designed to. Fortunately, there are many sizes and shapes of earplugs available, to suit each unique ear canal. One size earplug fits all is a myth”, Deason concludes.

Fit-testing hearing protection ensures both an appropriate choice of hearing protection and professional training on proper techniques to wear.  

A fit-testing success story from Norway

When choosing hearing protection for workers, employers still rely on single number rating (SNR) or noise reduction rating (NRR), which are features achievable under certain ideal conditions, not the actual noise reduction workers will benefit from. Noise reduction in the field can range from over 40 to zero decibels (dB) depending on whether a worker is using earplugs of the appropriate size and whether they are inserted correctly.

And this is what Beerenberg decided to find out, performing a fit test using Honeywell’s automatic technology, VeriPRO®. 288 workers were asked to choose their preferred earplugs from a selection featuring different models and sizes. Then, without any guidance on how to insert the plugs, the attenuation levels were tested. 

4 out of 10 employees achieved attenuation levels below the accepted threshold of 16 dB and 2 out of 10 workers, only 10 dB. 

Workers were provided with one-to-one advice on how to best fit the earplug in three simple steps:

1. Roll the earplugs into a small cylinder without creases or wrinkles. 

2. Pull the ear outwards to open the ear canal with the freehand, so that the earplug can be inserted further into the ear. 

3. Hold the earplug in place for a few seconds while it expands to fill the ear canal.

The training revealed which size or type of earplugs the worker needed, therefore, with the right fit, the proportion of workers with poor attenuation performance dropped to just over 5 percent.

97 percent of workers stated that they found the individual guidance on how to insert earplugs either useful or extremely useful.

The fit-testing experience has increased the awareness of the importance of selecting and fitting earplugs correctly. Nearly 80 percent of workers said that they had become more conscious about inserting the earplugs correctly and almost half of them said that they had experienced improved noise attenuation. Almost 70 percent said that the training made using earplugs better.

The long-term benefits of fit-testing

Although encouraging, the results of the training need to have long-term effects, as NIHL develops gradually and noise attenuation is important every day, for a long time. Therefore, a follow-up study was conducted a year after the training.

The target group consisted of 41 workers with initial attenuation levels lower than 16 dB during the first test. Just like in the first test, they were asked to choose the earplugs they typically used and insert them as they use to do, without any guidance.

20 workers achieved results over the acceptance levels, but those with results below rose to 21, from only 7 in the first training. However, this fit testing showed that the average noise attenuation had increased from 8.9 dB. to 17.1 dB and the employees displayed a significant improvement even 6-12 months after the training. 

However, the average noise attenuation value from the follow-up test, 17.1 dB is lower than the one from the test conducted immediately after the training, which was 22.5 dB. This means that even if the workers had achieved significant improvement after training, the average attenuation fell slightly during the year. Workers with scores below the acceptance criteria received new training, which lead to an impressive noise attenuation score of 26,9 dB.

Why don’t workers practice inserting the earplugs correctly?

The perceived usefulness of the training was supposed to be an answer, as workers who experienced a major benefit from the training and fit testing were more inclined to maintain the skill of inserting the earplug correctly.

To find out how workers perceived the effects of the training, a variable was developed to measure the perceived change in attenuation. This was calculated as the difference between the values from the first test and the follow-up carried out after fit-testing training. This test showed that for the workers who achieved less than a 10 dB increase in attenuation after the initial training, the average attenuation was now only 1.5 dB higher. 

The workers who experienced an increase of 10 dB or more following the initial training continued to achieve a significantly higher average attenuation score of 20.7 dB.

The role of individual training in increasing hearing protection

Tests led to a clear conclusion. 

Through simple methods such as individual counseling, testing of attenuation and possibly changing the type of earplugs used, employers can significantly increase the level of hearing protection offered to workers.

Adopting an individual approach to hearing conservation can also educate and motivate workershelping them discover the importance of using properly fitted earplugs and inserting them correctly.

The findings showed that more than half of the workers who initially received low attenuation fall back to below the acceptance criterion 6-12 months after receiving training. Those with good results during the training continued to achieve good attenuation levels. 

The conclusion is that refreshment training, continuous focus on hearing conservation but also selecting hearing protection devices that integrate fit-testing are crucial for ensuring the appropriate use of hearing protection and preventing occupational NIHL.

Here is a useful guide on how to start building your hearing conservation program today.