pdf Fit testing of respirators with ear loop straps (Vol. 41 No 1. 2024) Popular

Fit testing of respirators with ear loop straps

Nick Baxter*, Helen Beattie, Gillian Nicholls and Duncan Smith

Health and Safety Executive, Science Division, Buxton, Harpur Hill, SK17 9JN, UK

*Corresponding author and email:

ABSTRACT

Background: Due to large demand for respirators during the COVID-19 pandemic, particularly filtering facepiece respirators (FFP) level 3 (FFP3) in Great Britain (GB), an increasing number of FFPs with ear loop straps were imported into GB from outside of Europe. Many of these FFPs were incorrectly and often dually marked, showing a European “CE” (“Conformité Européenne”) mark which indicates conformance with the European standard BS EN 149 for respiratory protective devices (RPD), and a KN95 marking, which shows conformity to the Chinese standard GB 2626-2006 for respiratory protective equipment (RPE).

There is evidence suggesting FFPs with ear loop straps do not pass a fit test on a significant proportion of the intended population, with many studies throughout the world demonstrating a low fit testing pass rate of FFPs with ear loop straps.

Objective: The aim of this study was to evaluate the fit of KN95 style respirators with ear loop straps on volunteers representative of GB users, using a quantitative fit testing method.

Methods: Eight models of respirators with ear loop straps, with no certification documentation, were selected from different manufacturers. Quantitative fit testing using an ambient particle counting method was conducted on 29 volunteers. The order of the fit testing on each respirator was randomised. The study followed the fit testing protocol as described in Health and Safety Executive (HSE) guidance on RPE fit testing, INDG 479.

Results: From the 232 fit tests completed, only one achieved a fit factor above the pass/fail criteria of 100. The data showed a 95% confidence that the geometric mean of the overall fit factors lies between 3.0 and 4.7, and is significantly lower (P<0.05) than the pass/fail criteria of 100. Volunteer comments on the perceived fit of the respirators with ear loop straps included being loose on the face, and feeling leakage around the edges of the respirator. Discomfort of the straps around the wearers’ ears was also described.

Conclusion: The testing confirmed that there is a very low fit testing pass rate for FFPs with ear loop straps. Comments from volunteers also indicated that the perceived fit was poor.

Keywords: COVID-19 pandemic, healthcare, filtering facepiece respirators, ear loop straps, quantitative fit

test, KN95, discomfort, ears.