Measuring breathability and bacterial filtration efficiency of face masks in the pandemic context: A round robin study with proficiency testing among non-accredited laboratories. (15th February 2022)

• Record Type: Journal Article
• Authors: Tessarolo, Francesco; Nollo, Giandomenico; Benedetti, Luca; Helfer, Fabrizia; Rovati, Luigi; Ferrari, Alberto; Marchetti, Giulio; Reverberi, Federico; Baglio, Salvo; Tuccitto, Nunzio; Stefani, Stefania; Stracquadanio, Stefano; Caraci, Filippo; Terrasi, Antonio; Tricomi, Alessia; Musumeci, Mario; Miraglia, Andrea; Cuttone, Giacomo; Cosentino, Sofia; Agostino Vitali, Luca; Petrelli, Dezemona; Ilaria Ciancia, Sonia; Mingoia, Marina; Castellini, Paolo; Simoni, Serena; Montalto, Luigi; Baleani, Alessia; Chiariotti, Paolo; Paone, Nicola
• Is Part Of: Measurement. Volume 189(2022)
• Publication Date: 2022-02-15
• Subjects: Face mask -- Uncertainty -- Differential pressure -- Bacterial filtration efficiency -- Round robin -- COVID-19 -- SARS-CoV-2; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2021.110481
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: Intra-lot variability impacts uncertainty of face masks performance measurement. BFE measurements above 98% have good repeatability and reproducibility. High uncertainty can be associated to BFE measurements of community masks. Non-accredited laboratories performed at a satisfactory level during pandemic emergency. Face-mask conformity standards should consider uncertainty of BFE and DP measurements. Abstract: Six Italian non-accredited laboratories participated to an interlaboratory study aimed at measuring Differential Pressure (DP) and Bacterial Filtration Efficiency (BFE) of three face-mask models using methods in-line with EN 14683 standard. Methodological non-conformities were annotated. Repeatability and reproducibility on quintuplicate samples were calculated according to ISO 5725-2. Sample stability was also assessed. Laboratories were ranked according to the total standard deviation over all samples and proficiency was evaluated using z-score according to ISO 13528. Although some non-conformities were present, performances for the DP measurements were always acceptable. One laboratory had to revise the bacterial suspension preparation for the BFE test. Overall, non-accredited laboratories working during pandemic emergency performed satisfactorily. Sample-to-sample variability impacted measurement repeatability. BFE values above 98% showed good repeatability (≤1.0%) and reproducibility (≤6.1%), but high BFE uncertainty was associated to community masks. Our findings suggest that relevant face-mask conformity standards should consider uncertainty of BFE and DP measurements.