Brad Witt

Advancements in hearing protector fit-testing technology are now allowing safety managers and workers to more easily and accurately measure hearing protector effectiveness — and further bridge that “lab versus real world” gap between the published NRR and the actual use.


In recent posts, we've been discussing the role of hearing protector fit testing in hearing consevation programs and addressing the issues related to NRRs. We noted that fit-testing provides a formal metric from which one can determine whether employees are receiving optimal protection for their noise environment.

The value of fit-testing in helping wearers of hearing protectors close the gap between their real-world experience and their desired NRR was made evident in a field attenuation study conducted by the Howard Leight® Acoustical Laboratory. In the study, the real-world attenuation of earplugs worn by 100 noise-exposed workers at eight different noisy companies was measured.

In recent years, fit-testing of hearing protectors has become available from several manufacturers.  Similar to a qualitative respirator fit-test, an earplug fit-test assesses the actual protectors worn by the workers in the field. Learn More

In addition to the fact that the Noise Reduction Ratings (NRR), defined in EPA regulation, are simply population estimates, there are numerous other reasons behind the “lab versus worksite” gap, firmly rooted in the world of real human behavior.

They include:

At the heart of worker protection in any project is ongoing monitoring of the hazards.  Guesstimates of hazardous exposures, or conjecture about the effectiveness of protective equipment, are simply not acceptable in industry.

With the assistance of OSHA’s Office of Information and Technology, we analyzed OSHA compliance actions for the five-year period from 2000-2004. During this period, more than 10,000 violations were cited in reference to OSHA’s Occupational Noise Standard (29 CFR 1910.95), with accompanying initial penalties over $7.5 million*.

The best hearing protector device (HPD) in the world does no good if it is not worn. Yet the most common problem for safety professionals in administering Hearing Conservation Programs is exactly that: getting workers to wear their HPDs.
Here are some thoughts to improve your compliance rates.

Q&A Time: Questions from the HearForever Community...

Question: Why aren't earplugs made with higher attenuation ratings -- like 40, or 50 or 60 dB?

Answer: There are three limits that cap attenuation of an earplug in the mid-30 dB range.

Q&A Time: Questions from the HearForever Community...

Question: We have foam earplugs which we wash and reuse. Does washing them have any effect on their published attenuation? Will washing them diminish their strength?

Answer: Washing of foam earplugs does not have a major effect on strength or attenuation, but... foam earplugs do retain moisture. You can never "squeeze" it all out. And that has two negative after-effects:

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