August 7, 2018 / Jeremy Sheppard

Real-world Problems with Mask Fit-Testing

Sponsored by OHD, LLLP

Work is dangerous, and industrial hygienists know that danger is not a finite resource—it has to be stamped out wherever it’s found. When workers are protected and respirators fit correctly, your workers live longer, healthier lives.

But to ensure proper fit-testing, you need a plan and the right tools. The problem is that fit-testing can be hard, frustrating, and expensive. There are four main problems people face while fit-testing respirators:

1. People don’t like fit-testing.

When people hate fit-testing, they tend to tighten the mask as much as possible to ensure a good fit, but most times this can cause higher fail rates. The bigger problem is that if the respirator doesn’t fit accurately for actual use, wearers are risking dangerous exposures.

If the worker looks uncomfortable, coach him or her to wear the mask comfortably. By using the seal-check feature with testing units, you can know quickly and reliably if a seal is good or not.

2. One mask can’t fit everyone.

People are diverse, and their shapes and face sizes vary. This directly affects respirators. When a site chooses one type of respirator and only offers one or two sizes of that mask, problems will arise.

When size choices are limited, the fit-tester tends to take the blame, when in reality a lack of respirator choice could cause fewer people to pass. Offer multiple sizes and makes of respirators so that workers have the ideal size and fit for them.

For more information, see OSHA’s Personal Protective Equipment standard, 1910.134(d)(1)(iv):

“The employer shall select respirators from a sufficient number of respirator models and sizes so that the respirator is acceptable to, and correctly fits, the user.”

3. People change.

A common complaint against respirator fit-testing is, “I’ve been wearing this same mask since I started here, 18 years ago!” Over that amount of time, people experience physiological changes. Weight fluctuation can have a large impact on respirator fit along with changes in the texture of people’s faces as they get older.

For more information, see 1910.134(f)(3):

“The employer shall conduct an additional fit test whenever the employee reports, or the employer, PLHCP, supervisor, or program administrator makes visual observations of, changes in the employee's physical condition that could affect respirator fit. Such conditions include, but are not limited to, facial scarring, dental changes, cosmetic surgery, or an obvious change in body weight.”

4. Particles and environmental conditions.

You have a line of people waiting to be fit-tested. You’re under pressure to get them in and out quickly, but the machine doesn’t have enough particles to operate, and you’re stuck.

Respirator fit-testing doesn’t have to be so hard.

Particles add an unnecessary variable into the equation. Instead of using manufacturing particles, some testing units use air, a universal challenge agent, to test respirators.

When you use air and controlled negative pressure (CNP), you can fit-test without relying on particles, and that means more people can be fitted more quickly, with less stress and higher accuracy.

Imagine a work force that has fewer work injuries, fewer respiratory complaints, and increased productivity.

Let’s Talk about Respiratory Protection

OHD has helped thousands of industrial hygienists with fit-testing to protect workers around the world. For more information, visit the OHD website.

Jeremy Sheppard

Jeremy Sheppard is a Fit Testing Consultant with OHD, LLLP.


IH Consultant

Due to COVID and shortage of N-95 we are sourcing many different makes and models that we do not normally use and have found some of the NIOSH approved N-95 respirators that doesn't fit anyone. We have tried adjusting and attempting to reseal the respirator without success. We were successful with fit testing these individuals with a different respirator. Have you seen this with any of the so called "Universal fit" respirators?

By Keith Rowland on February 23, 2021 9:33am
question about amyl acetate used for fit testing

Using an ASTM Level 1 surgical mask with tape around all of the edges and no sign of leakage, there should be "N95" filtering capability. But I can smell the amyl acetate with the mask on before the test even begins. The same thing happens with an R95 mask, also fitted well and sealed with tape for good measure. What is going on?

By Margaret MacDonald, MD on July 9, 2020 6:43pm

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