Design Reality

Passing Your Face Fit Test

It is employers’ responsibility to ensure that the now mandatory RPE for dentists can adequately protect them. Yet most practice managers delegate the purchase of RPE to their employees or buy the same model for all. Whilst most purchasing decisions are guided by cost savings, product efficiency and utility, choosing the right personal RPE is a gamble. (It doesn't have to be, though, if you consult our 10-Step Guide on Choosing the Right PPE).

Each person’s unique facial size, shape and features fit the same mask differently, so the only way to be sure that a mask is a perfect fit is through a face-fit test. However, passing a face fit test is not guaranteed for anyone, regardless of mask model or how many times the test was performed. Such is the case of Dr Maria Lipovanska, a dentist who came to Design Reality after failing the face-fit test in three different mask models. Dr Lipovanska turned to our 20-year expertise in respiratory design with the hope that we could identify the problem and recommend a model that fit.

The Problem

Dr Lipovanska, of the Menai Bridge {mydentist} practice and the Belmont House Dental in Rhos-on-Sea, failed her face fit tests in the 4255+ half-mask P3 respirator by 3M, the JSP Force 8 P3 mask and the Stealth P3 reusable half-face mask. Each fit test was performed by a different tester, in the  different practice locations of her employers.

According to UK legislation, apart from the initial test that confirms optimal mask selection, subsequent testing has to be carried out whenever there is substantial change to the person, such as occurs with dental work, plastic surgery or weight change. Knowing that her own safety and her patients’ lives depended on her protection during aerosol-generating procedures and faced with the prospect of undergoing further fit testing in the future, Dr Lipovanska’s utmost wish was to find a mask she could commit to; one that could not only pass the fit test, but that could be used confidently for years.

Fit tests take about an hour, cost approximately £45, involve the use of additional props and must be performed by trained testers. The tests can be qualitative or quantitative; the first type assesses the subjective olfactory senses to determine how well a mask can block out hazardous airborne particles. A qualitative fit test results in a Pass or Fail reading, depending on how the tested individual responds to either a sweet or bitter taste-simulating reagent. The subject’s head and shoulders are covered with a special hood, then Bitrex or Saccharin are sprayed under it. Not being able to taste these chemicals is a sign that the mask fits well and that there are no leaks or product breaches. This is the type of test that Dr Lipovanska failed thrice before coming to Design Reality. Besides wasting precious clinical time and personal resources, Dr Lipovanska found the qualitative tests unpleasant and inconclusive. With her head covered, she had to perform a series of physical exercises, from marching in place to bending and counting backwards from 100. She could taste the Bitrex as soon as she started to speak. The next model mask she tried fitted so loosely that the tester gave up on testing her altogether. No-one could recommend a model to Dr Lipovanska; she was told to keep trying other masks until she found one that fit. Eventually, she passed in a loose-fitting mask and a rubber dam folded on her nose. She was advised to wear that mask with the additional contraption every time, but also buy a second of each for her other workplace. That didn’t sound safe to her, so Dr Lipovanska decided to contact Fit2Fit certified testers at Design Reality.

The Solution

A quantitative fit test, which is the type that Design Reality offers, uses sophisticated equipment to assess the penetration of microscopic particles in ambient air, resulting in a numerical “fit factor. Our Portacount machines work with a particle generator that disperses a saline solution, mimicking the environment during aerosol generating procedures. We can test full or half reusable masks, as well as disposables.

Because the qualitative test depends upon a person’s odour sensitivity, its results can be inaccurate due to subjective factors, such as olfactory fatigue. In addition, the test can be failed if the mask’s straps aren’t tightened enough or if the seal is breached during exertion and deep breathing. With the qualitative test, detecting the taste-simulating substance is the only barrier to obtaining a passing certificate.

Our quantitative fit test is graded on achieving a minimum passing or “fit” factor, which is an objective estimate of the fit of a certain respirator to a specific individual. A fit factor deduces the ratio of the concentration of a substance in ambient air to its concentration inside the respirator. We use ambient aerosol condensation nuclei count (CNC) as our fit testing protocol agent and laser technology to measure aerosol concentrations inside and outside the respirator. Dr Lipovanska didn’t stand in a test chamber or have her head covered, nor was she asked to report on subjective experiences. Instead, our Fit2Fit trained MD, Troy Baker, educated her on the best suction procedure, demonstrated how to secure the straps and ensured that the filters were correctly positioned.

 Our product knowledge is just one of the differentiating factors to our fit tests. Another is that our test subjects can see the difference in their fit factors before and during the test.  The screen in front of them shows in real time how their every movement impacts their protection. This is very important to dentists, who often tilt their heads at odd angles whilst examining patients. Last but not least, unlike the subjective verification of a qualitative test, our test has no protection-factor limit. For half-mask respirators, our passing factor is 100 and for full masks – 2000. We provide full documentation of all numerical results.

Dr Lipovanska walked out of Design Reality’s office with her new mask and a Fit2Fit pass certificate. Our Fit2Fit-certified MD was able to immediately identify the right model and size for her, and recommended suppliers for the replaceable filters. Needless to say, Dr Lipovanska is one happy customer and we have been glad to help. The important issue that this case uncovered for us is how out-of-date some RPE mask designs can be, having been created for male-heavy industries with no consideration for the smaller features of Dr Lipovanska and other women. Comprising a pivotal segment of our army of frontline workers, women deserve a sleek, light and clean design they can wear with confidence. Design Reality is currently designing the next generation of respiratory protection for a client and we cannot wait to show our next revolutionary product design.

So watch this space with bated breath (pun very much intended!).

Ellie Yakimov

Marketing Manager