School of S&T tasked with testing face masks and disinfectants
13 July 2020
The School of Science and Technology (S&T) was commissioned by HKET TOPick to test six common face masks and six disinfectant products. The mask test aimed to establish whether bacterial filtration efficiency (BFE) could be affected by heat or humidity. Based on the ASTM F2101 testing standard, Associate Professor in Testing and Certification Dr Eric Sze tested two surgical masks of different brands, a bamboo charcoal fibre mask, an N95 respirator, a cotton mask and a photocatalyst mask. It was found that after eight hours of simulated wearing at 37°C and 90% humidity, the surgical masks, the bamboo charcoal fibre mask and the N95 mask still maintained a BFE of over 99%, while the BFE rate of the cotton and photocatalyst masks dropped by 10%.
The test on disinfectants involved a hydrogen peroxide solution, two disinfectant sprays and three alcohol-based hand rubs, and followed test methods for antibacterial-finished products. As it turned out, all specimens exhibited a bacteria-killing rate of over 99%; however, one alcohol-based rub recorded approximately 110 cfu in Staphylococcus aureus residue. According to Dr Sze, that particular hand rub could have been compromised by a reduction in alcohol concentration over time or due to poor storage. Noting that four of the specimens contain antibacterial agents, some of which could cause poisoning through long-term oral ingestion, he also warned against direct contact with food after applying these sanitizers to the hands or using them to disinfect tableware.
