Dental Tribune India

Fit (seal) test of your Respiratory Protective Equipment (RPE) decides if you are well protected

By Rajeev Chitguppi, Dental Tribune South Asia
May 25, 2020

Dr Waris Patel explains the importance of fit test/ seal test that is mandatory in many countries to check if the Respiratory Protective Equipment (RPE) are good enough to ensure the safety of healthcare professionals.

Respiratory Protective Equipment (RPE) must be checked for the adequacy of fit/ seal as a legal requirement of employers in some countries so that employees are safe in cases of occupational hazard this has is now applied to dentistry since COVID-19.


As people’s faces come in different shapes and sizes we can not expect one size of RPE facepiece will fit everyone. It must not leak to provide adequate protection.

Fit testing will ensure that the equipment selected is suitable for the wearer. The air being breathed in needs to be channelled to the filters – any gaps around the edges of the mask will create a path of least resistance allowing potentially contaminated air to be inhaled bypassing the filters.

The mask requires correct placement and seal which can not be achieved with facial hair including stubble so being clean-shaven will be a requirement. For those who need to keep a beard, there are alternative forms of RPE that do not require a tight fit to the face eg full respirator with hood.

Following successful testing, records need to be kept of the make, model, type and size of facepiece; different masks in the future will require retesting.

Fit testing is assessed Qualitative and Quantitative

Qualitative method utilises an aerosol introduced into a hood of either a sweet-tasting material (Saccharine) or a bitter (Bittrex) to confirm the integrity of the face seal whilst the wearer undertakes a number of exercises after this period the wearer has not detected (tasted or smelled) the test material, then that is accepted as a pass and a fit factor of 100 is assigned.

It is part of the protocol that at the end of the test, the candidate is required to break the seal to confirm how effective the seal has been.


Quantitative Method is about precise using of a Portacount particle counting device. This device counts the particles inside the wearer's respirator and compares this to the ambient atmosphere. At the end of each of the exercises (conducted whilst the wearer is walking on a treadmill, stepper or just on the spot) a calculation is made of the Fit Factor. This device is connected with a tube to the mask.


Dr. Waris Patel
Qualified BDS Liverpool university 1992; Canadian dental license 2000.
Runs a private dental practice in the Northwest of England with interests in
intravenous sedation,
dental implants,
cosmetic, microscopic and reconstructive dentistry.

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