The International Society for Respiratory Protection

pdf Human Errors in Qualitative Respiratory Protective Equipment Fit Testing: A Study of Real-World Fit Testers (Vol. 41 No. 1 2024)


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Human Errors in Qualitative Respiratory Protective Equipment Fit Testing: A Study of Real-World Fit Testers

Karen M. Long1,*, Nathalie Mai1, Michael Williams1

  1. Cranfield University, Cranfield Defence and Security, Bedford UK.


* Corresponding author email:


Background. Fit testing is an essential part of any respiratory protective device program and provides a method for assessing the effectiveness of the face-to-facepiece seal of a tight-fitting facepiece which helps to assure wearer protection. Although qualitative fit test methods are assumed to be simple and easy to use, it remains critical that the methodology is applied in accordance with the protocols set out in guidance to ensure that a correct ‘pass’ or ‘fail’ result is assigned. An incorrectly assigned pass result increases the risk to the wearer of exposure to hazardous respiratory substances in the workplace, putting their health or life in danger. Fit testing stakeholders, manufacturers and regulatory bodies have raised concerns about the quality of fit testing conducted in the UK workplace, but there have been no published research studies in this area to date.

Methods. This article presents results from a study into the errors made by real-world qualitative fit testers, using the data gathered during Fit2Fit practical assessments conducted in the UK over a ten-year period from 2009 to 2019.

Results. When application of the qualitative fit test method was measured against the HSE INDG479 protocol, assessment records indicate that fit testers made a median of 4 errors, and a high of 29 errors. Fit2Fit accredited fit testers appear to make half as many errors as non-accredited fit testers, yet the scheme remains voluntary in the UK. The sources of errors were analysed in detail and revealed that the most common errors were made in instructing the wearer, donning and fit checking RPE, verifying the nebuliser function, and assuring the wearer’s taste detection.

Conclusion. Results from this study suggest that errors made by real-world fit testers are common, and steps to mitigate the assignment of false pass fit test results arising from these errors are needed if wearer health is to be better protected.

Keywords: Qualitative fit test, QLFT, FFP3 respirator, half mask respirator, Fit2Fit, competency.