A performance evaluation and inter-laboratory comparison of community face coverings media in the context of covid-19 pandemic

International audienceDuring the recent pandemic of SARS-CoV-2, and as a reaction to the worldwide shortage of surgical masks, several countries have introduced new types of masks named “community face covering” (CoFC). To ensure the quality of such devices and their relevance to slow down the virus spreading, a quick reaction of the certification organisms was necessary to fix the minimal acceptable performances requirements. Moreover, many laboratories involved in the aerosol research field have been asked to perform tests in a quick time according to (CEN, 2020) proposed by the European committee for standardization. This specification imposes a minimal air permeability of 96 L.m-2.s-1 and a minimal filtration efficiency of 70% for 3 µm diameter particles. In the present article, an intercomparison of efficiency and permeability measured by 3 testing laboratories has been performed. Results are in good agreement considering the heterogeneity of the considered material samples (within 27 % in terms of filtration efficiency and less than 20 % in terms of permeability). On this basis, an analysis of 233 materials made of woven, non-woven and mixed fibrous material has been done in terms of filtration efficiency and air permeability. For some of them, measurements have been performed for 0.2 µm, 1 µm and 3 µm particle diameters. As expected, no deterministic correlation could be determinated to link these efficiencies to the permeability of the considered samples; however, a trend could be identified. The same exercise has been conducted to link the filtration efficiency measured at 3 µm to the filtration for lower diameters. Finally, a discussion on the kind of material that is the most relevant to manufacture “community face covering” (CoFC) supported by spectral filtration efficiency (from 0.02 µm to 3 µm) is proposed