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     Face Fit


What is a Quantitative face fit test?...


Quantitative face fit testing (QNFT), also know  as Ambient Particle Counting (APC) or the “Portacount” method provides a numerical measure of the Respiratory Protective Equipment’s (RPE) seal or effectiveness. This is known as a fit factor.

These tests give an objective and quantifiable measurement of the face fit, something not offered with a qualitative test.

Quantitative testing requires specialised equipment that uses laser diffraction to identify and count near microscopic particles in the surrounding atmosphere and compares that to the particle count with in facepiece. This method is more accurate and tests to more stringent parameters than a Qualitative test (QLFT).

QNFT is required for all close fitting full face respirators and can also be used on half face RPE (disposable or reusable). A qualitative test can only be utilized on half mask respirators offering particulate protection i.e. FFP3.

Here at 1974 Rapport, we have invested heavily in the very latest equipment, namely the TSI Portacount 8048, this latest equipment allows us to test on a whole range of close fitting RPE including FFP2 devices using the N95 comparison setting.

To perform the test, firstly we must prepare a test piece using either a probe or adapter to facilitate the particle count within the RPE. Once calibrated and with the mask worn correctly; the wearer is expected to perform a series of rigorous exercises where the APC equipment takes live measurement of the seal efficiency.

The advantages over Quantitative face fit testing over Qualitative include…

  • The test does not rely on taste

  • The outcome cannot be manipulated by the wearer

  • Can be used for full face RPE

  • Tests down to a smaller particle size range

  • Gives a quantifiable outcome as opposed to just “pass or fail”

Face fit testing must be undertaken by a competent person; here at 1974 we are externally assessed by the BSIF Fit2Fit accreditation scheming in both QNFT, QLFT & QLFT “Train the Tester”.  Our credentials can be verified here

All testing undertaken by 1974 Rapport is strictly in line with current best practice detailed within HSE INDG479 and the accompanying Fit2Fit Companion.


For further information, to make a booking or to receive some competent advice, please don’t hesitate to get in touch.

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