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Assessing the performance of community face coverings

Jesus Alejandro Marval Diaz

Assessing the performance of community face coverings.

Rel. Paolo Maria Tronville, Valeria Chiono. Politecnico di Torino, Corso di laurea magistrale in Ingegneria Biomedica, 2020

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The World Health Organization (WHO) has found that coronavirus disease 2019 (COVID-19) is transmitted via droplets and fomites during unprotected exposure in the immediate environment of those infected. Several studies concluded that wearing facemasks reduces virus transmission. Most national strategies to respond to the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) pandemic included, among others, the use of face masks to reduce the infection propagation. For this reason, just a few weeks after the COVID-19 epidemic started, there was a massive increase in face masks demand, and a shortage occurred. Major providers of facemasks increased their production as much as four times their typical output, but this was not enough to fulfill the market demand. Moreover, facemask-manufactures faced a lack of non-woven material, which is a vital component of most face masks. Some other companies modified their original production and, to try to meet consumer demand, started to producing face masks made up of other available materials, like cotton. These products do not guarantee the minimum performance requirements of medical masks or personal protective equipment (PPE) for the respiratory tract. In Italy, this third category is called “community masks” and was lacking a specific test method and rating system to regulate its presence on the market. Current standards test methods to assess the performance of medical masks (EN 14683) and PPE for the respiratory tract (EN 149) prescribe complicated and lengthy test methods using equipment out-of-date, i.e., challenging to find in the market. For example, the Bacterial Filtration Efficiency (EN 14683) takes at least two days to be measured, and it requires the use of the pathogenic Staphylococcus aureus. Moreover, the uncertainty of the reported data of these two standards is not clearly defined. We developed an innovative test method to measure the filtration performance of the “community masks”. In this way, we can provide more useful and complete performance assessments in a much shorter time and with a defined uncertainty. Furthermore, this new test method can be performed in a typical laboratory by using instrumentation commonly used for assessing the performance of air filtering media and devices and without using a biological test aerosol. We compare the data obtained with current standardized test methods with those provided by the innovative test method. This comparison was performed by testing the three categories of protective devices mentioned above (medical masks, PPE for the respiratory tract, and “community masks”). Our analysis shows that the performance of “community masks” covers a vast range of removal efficiency, starting from almost zero and reaching efficiencies like the ones of certified medical masks. We also analyze the breathability of all those products. Finally, we propose a new approach to classify the “community masks” and to provide solid ground for ensuring their minimum performance requirements.

Relators: Paolo Maria Tronville, Valeria Chiono
Academic year: 2019/20
Publication type: Electronic
Number of Pages: 88
Corso di laurea: Corso di laurea magistrale in Ingegneria Biomedica
Classe di laurea: New organization > Master science > LM-21 - BIOMEDICAL ENGINEERING
Aziende collaboratrici: UNSPECIFIED
URI: http://webthesis.biblio.polito.it/id/eprint/14945
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