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Comparative Study
. 2021 Feb 8;18(4):1599.
doi: 10.3390/ijerph18041599.

Comparative Performance Testing of Respirator versus Surgical Mask Using a Water Droplet Spray Model

Paul T J Scheepers  1 , Heiman F L Wertheim  2   3 , Maurice van Dael  1 , Rob Anzion  1 , Henk Jan Holterman  4 , Steven Teerenstra  5 , Martijn de Groot  6 , Andreas Voss  2   3   7 , Joost Hopman  2   3
Affiliations
Comparative Study

Comparative Performance Testing of Respirator versus Surgical Mask Using a Water Droplet Spray Model

Paul T J Scheepers et al. Int J Environ Res Public Health. .

Abstract

Background: During the SARS-CoV-2 pandemic, there was shortage of the standard respiratory protective equipment (RPE). The aim of this study was to develop a procedure to test the performance of alternative RPEs used in the care of COVID-19 patients.

Methods: A laboratory-based test was developed to compare RPEs by total inward leakage (TIL). We used a crossflow nebulizer to produce a jet spray of 1-100 µm water droplets with a fluorescent marker. The RPEs were placed on a dummy head and sprayed at distances of 30 and 60 cm. The outcome was determined as the recovery of the fluorescent marker on a membrane filter placed on the mouth of the dummy head.

Results: At 30 cm, a type IIR surgical mask gave a 17.7% lower TIL compared with an FFP2 respirator. At 60 cm, this difference was similar, with a 21.7% lower TIL for the surgical mask compared to the respirator. When adding a face shield, the TIL at 30 cm was further reduced by 9.5% for the respirator and 16.6% in the case of the surgical mask.

Conclusions: A safe, fast and very sensitive test method was developed to assess the effectiveness of RPE by comparison under controlled conditions.

Keywords: COVID-19 pandemic; aerosols; particle size distribution; respiratory protective equipment; virus transmission.

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Conflict of interest statement

Both A.V. and J.H. participate as experts in the WHO Health Emergencies Program (WHE) ad-hoc COVID-19 IPC Guidance Development Group (COVID-19 IPC GDG).

Figures

Figure 1
Figure 1
Particle size number distribution in the spray of water droplets at 30 and 60 cm.
Figure 2
Figure 2
Test set-up for total inward leakage (TIL) test at 30 cm distance (a); Sheffield head with membrane filter placed in the mouth opening (b); 3M FFP2 Aura mounted on dummy head before (c) and after (d) spray sequence (with the yellow stain of fluorescein showing soiling of the respirator).
Figure 3
Figure 3
TIL expressed as recovered fluorescein at 30 cm (N = 10–16) (a) and 60 cm (N = 5) (b). The diamonds correspond to the means.
See this image and copyright information in PMC

Comment in

References

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