Face Fit Test Exercises: Are You Following Them Correctly?

For those who rely upon Respiratory Protective Equipment (RPE) to carry out their work, ensuring a proper face fit is crucial for their personal safety. During a Face Fit Test (FFT), following the correct procedures and exercises can make the difference between achieving adequate protection and exposing the wearer to hazardous airborne particles.

In this article, we’ll outline the key factors that will help you verify that you're correctly performing FFT exercises, based on the UK Health and Safety Executive (HSE) guidance INDG 479.

The Pre-Test Check

Before starting a Face Fit test, thoroughly inspect the RPE to ensure it is in good condition, particularly around the exhalation valves and head harness. If any component is noted or suspected to be faulty, do not proceed with the test as a damaged mask will not provide adequate protection. This simple but necessary check will help ensure accurate test results, as any flaws in the mask will compromise the validity of the assessment. Checking the expiry dates of masks and filters is a simple but important pre-use check.

It is also important that the wearer is able to correctly don the respirator in accordance with the manufacturers’ instructions and is permitted to wear the mask for at least 5 mins prior to starting the test process to ensure it is comfortable. This will also allow time for the mask to “warm up” and soften to the face. Natural moisture will usually improve the performance of the mask but can also attract dust hence why the mask should be washed and cleaned thoroughly if it is to be re-used.

Face Fit Test Exercises

Whether a qualitative or quantitative face fit test is being performed, the HSE recommends seven exercises, each of which should last for at least one minute. These exercises - normal breathing, deep breathing, turning the head from side to side, moving the head up and down, talking, bending over and a repeat of normal breathing as well as, in some cases, a physical action, such as stepping - should be conducted while wearing the mask. These movements are intended to replicate the variety of movements and actions that a user is likely to perform during their work and so including these within the test process should ensure that the mask fit will not be compromised in the working environment.

Qualitative Testing Protocol

The qualitative test is a sensory-based evaluation which requires a test solution. When carrying out this test, apply the required number (10, 20 or 30) of pumps of the solution to saturate the air around the mask retained within a test hood; a sensitivity test should be conducted beforehand in order to determine the concentration required. Once present in the test hood, the test can begin, and the fit test exercises commence; this time should be noted, or a stopwatch started at this point. To maintain the required concentration, “top up” pumps of the test solution should be administered (with this time the quantity being half the starting amount) every 30 seconds from the test start time and during each exercise. All exercises need to be conducted directly one after the other, without pause or hesitation, each for one minute without forgetting to add the “top-ups”. The wearer should be in a standing position. If they detect the test solution at any time during the test, then the mask is considered to have leaked, and the test is considered unsuccessful. A wearer should not be permitted to wear a respirator mask unless a successful test has been undertaken. If the wearer does not detect the test solution at any time during the 7-minute test, then a validation (often referred to as a “reveal”) should be conducted to confirm that the test is indeed successful and correctly performed.

Quantitative Testing

In a quantitative face mask fit test (QNFT), an objective measure of fit is obtained using an electronic instrument such as a Condensing Nuclei Counter (CNC), Ambient Particle Counting (APC) or Controlled Negative Pressure (CNP) machine. These methods usually measure and quantify any leakage and report a measured fit factor from the mask being worn.

Controlled Negative Pressure

The CNP test measures pressure changes inside the mask while the device creates and maintains a negative pressure within it. Any pressure change is considered a result of mask leakage however such changes can occur when the wearer is not accurately holding their breath during the measurement or small movements. For this reason, when using this method, the wearer should undertake a period of activity (exercise) before the test machine takes a test measurement and then stand still and hold their breath for the 8-10 seconds it takes for the machine to take each measurement. This ascertains if the mask has shifted during the movement; if the measurement is successful the wearer can progress to the next exercise. A successful test results when all measurements have been correctly taken, demonstrating an acceptable leakage rate into the mask. If in the UK and following the UK INDG 479 protocol, this test should include the same 7 exercises as above, each being undertaken for 60 seconds before measurements are taken. Two measurements are taken at the end of the look left/right and look up/down, hence why a total of 9 successful measurements is required for the test to be considered successful.

Ambient Particle Counting (APC)

The CNC (known as APC in the UK) test measures particle density inside and outside the mask cavity and then compares these two measurements. If they are similar then the mask is not effective. If the inner measurement is considerably lower than the outer ambient air measurement, then the mask is likely to have an effective seal to the face of the wearer; since the extent of the ratio between these numbers indicates the effectiveness of the seal it can be considered a measure of leakage. This assumes that any particles found within the mask have leaked in and that there are enough particles in ambient air to show that the mask is effective.

As these measurements can be continuous, they can be taken during any movements or exercises and indicate the effect of the movements on the seal of the mask. However, to avoid errors only one measurement can be taken at a time. For this reason, when conducting the test, samples are taken from outside and inside the mask at alternative intervals. If following the UK INDG 479 protocol, the sample should be taken from inside the mask for at least 60 seconds meaning that with this test, the total exercise time must be increased to allow the out-of-mask sample to be taken. This results typically in an exercise time of 80 or 84 seconds (possibly longer depending on the testing device used) to allow the machine to purge and sample accordingly; this time should include and be a continuation of the movement of the exercise and should not be considered as a pause, hesitation or rest. Pausing or resting between exercises will impact the quality and value of the test itself, potentially resulting in a false pass result. In addition, INDG 479 calls for the wearer to undertake a stepping exercise (stepping up and down on a step) throughout the test (other than for the bending exercise) although other options, such as walking on a treadmill or cycling on an exercise bike, are also acceptable

The Importance Of Fit2Fit Accreditation

For accurate and reliable results, the HSE endorses the Fit2Fit Accreditation scheme which verifies the competence of face fit testers or fit test technicians in their chosen fit test method. Fit2Fit accreditation intends to provide some assurance that technicians can follow the face fit testing requirements in accordance with the protocols required in their region of operation. At Fire Safe International, we are proud to be able to state that all of our fit test technicians are Fit2Fit accredited, most in more than one fit test method, meaning you can have confidence in our professionalism and ability to assist you in ensuring your staff are adequately protected and that our training instructors can deliver high-quality training that meets or exceeds the demands of HSE INDG 479. We can also provide training and support to others wishing to become accredited themselves.

Find Out More

If you would like to find out more about our accredited Fit2Fit FFT training, please get in touch with Fire Safe International at 01743 761000 or book your qualitative fit test course today.

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