Are surgical masks manufactured from sterilisation wrap safe?

Abstract

Background: Due to regional shortages some health services have proposed using surgical masks manufactured from sterilisation wrap. However, there has been little assessment of the safety of this practice. Therefore, we developed our own prototypes and evaluated whether they met regulatory standards. Methods: Surgical mask prototypes were manufactured from two thickness grades of commercial sterilisation wrap. Safety was assessed in the context of regulatory standards. As it was not previously reported, we developed and performed differential pressure and synthetic blood penetration resistance experiments in accordance with official methodology. Results: Bacterial filtration efficiency was comparable between sterilisation wrap and commercial surgical masks. Both prototypes met regulatory standards for synthetic blood resistance, whilst only our thinner mask fulfilled acceptable differential pressure ('breathability') thresholds. Conclusion: Acceptable barrier and breathability properties can be achieved with surgical masks produced from sterilisation wrap. Therefore, this may be a reasonable method to supplement stock if required. Unless there are shortages mandating alternatives, health-care workers should always use approved personal protective equipment.

Comparison of filtration efficiency and respiratory resistance of COVID-19 protective masks by multi-national standards

“…There are several standards used worldwide to determine the PFE of masks, such as the GB 2626-2019, NIOSH, BS EN 14683:2019, AS/NZS 1716:2012, JIS T8151:2018 and so on. 20 , 21 , 22 In this work, we systematically measured the PFE of different kinds of masks using the EN 149:2001+A1:2009 (EN 149+A1), GB 2626-2019 and NIOSH 42 CFR Part 84-2019 standards, respectively.…”

Spunbond-Meltblown-Spunbond ou Tecido-Não-Tecido para proteção respiratória de trabalhadores da saúde

“…De acordo com um estudo sobre a segurança das máscaras cirúrgicas fabricadas com envoltório de esterilização 9 , a eficiência de filtragem de partículas da máscara produzida com invólucro de esterilização é muito menor do que a de um respirador N-95 aprovado pelo Instituto Nacional de Segurança e Saúde Ocupacional (NIOSH, por sua sigla em inglês) dos Estados Unidos, mas está dentro do alcance de uma máscara cirúrgica, com respirabilidade aceitável. Ressalte-se que a autoclavagem desses invólucros não afetou a eficiência da filtragem de partículas ou a resistência à respiração do SMS e TNT 16 .…”

“…As camadas do SMS são elaboradas de duas maneiras: a primeira e a terceira, chamadas spunbonds, são produzidas com fibras curtas depositadas sobre uma superfície quente, e a segunda, o meltblown, é de fibras fundidas, que são separadas por um bico fino 9 .…”

The use of fibrous face masks as a barrier against infectious biological airborne particles

“…There was no description about the type of non-medical masks used for these tests. 45,46 Single cloth masks efficiency against particles that are less than 300 nm was between 5-80% and for particles greater than 300 nm it was between 5-95% and when multilayer cloth was used, the efficiency was greater than 80% for particles that are less than 300 nm and for particles greater than 300 nm it was greater than 90%. Cloth and surgical masks tested for cough aerosol transmission using respiratory aerosol simulators showed a 40-60% reduction.…”