The impact of extreme reuse and extended wear conditions on protection provided by a surgical-style N95 filtering facepiece respirator

Duncan, Scott; Bodurtha, Paul; Bourgeois, Cara; Dickson, Eva F. Gudgin; Jensen, Cheryl A.; Naqvi, Syed Ali Raza

doi:10.1080/15459624.2020.1829633

Cited by 6 publications

(8 citation statements)

References 21 publications

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“…One of the most dynamic elements, respirator-to-face seal or the fit of the N95 FFR onto the wearer's face, is not accounted for. However, there is guidance 18 and data 19 suggesting that the face seal can be maintained for up to 5 donning/doffing events with no visible deformation or soiling. Further studies are needed to determine whether filtration efficiency is retained after repeated VHP processing runs.…”

Section: Discussionmentioning

confidence: 99%

Vapourized hydrogen peroxide decontamination in a hospital setting inactivates SARS-CoV-2 and HCoV-229E without compromising filtration efficiency of unexpired N95 respirators

Christie-Holmes

Tyli

Budylowski

et al. 2021

American Journal of Infection Control

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Section: Discussionmentioning

confidence: 99%

Vapourized hydrogen peroxide decontamination in a hospital setting inactivates SARS-CoV-2 and HCoV-229E without compromising filtration efficiency of unexpired N95 respirators

Christie-Holmes

Tyli

Budylowski

et al. 2021

American Journal of Infection Control

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“…They must limit the mass penetration of non-oil-based particulates to <5%, and they must provide a fit factor (FF) ≥100 when quantitatively fit to individuals; a quantitative fit test (QNFT) only measures inward leakage at the face seal. Measured protection factors (PFs) of N95 FFRs when worn in the workplace have been shown to give considerably lower protection [ 58 , 59 ], and both the Canadian Standards Association (CSA) and the US Occupational Safety and Health Association (OSHA) have given these respirators an assigned protection factor (APF) of 10 [ 76 , 77 ]. For disposable procedure/surgical masks and reusable fabric face coverings, there is no requirement to provide a specific level of protection performance, whether for filtration efficiency or inward leakage.…”

Section: Introductionmentioning

confidence: 99%

“…Masks that have been in use during the SARS-CoV-2 pandemic can be broadly categorized into five groups; i) re-purposed apparel such as scarfs, neck warmers, bandanas, etc., ii) simple fabric masks of one or two layers, iii) fabric masks with an included layer specifically to augment filtration efficiency, iv) disposable procedure/surgical masks of the kind used in health care settings, and v) certified filtering facepiece respirators (FFR), such as FFP2, KN95 and N95 masks. N95 FFR are employed as personal protective equipment (PPE) and they provide a high level of protection for filtering facepiece masks that cover only the nose and mouth (as opposed to full and half-face respirators constructed from elastomeric materials) [3,[58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74]. N95 FFRs are certified under the National Institute for Occupational Safety and Health (NIOSH) [75].…”

Section: Introductionmentioning

confidence: 99%

The protective performance of reusable cloth face masks, disposable procedure masks, KN95 masks and N95 respirators: Filtration and total inward leakage

2021

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Face coverings are a key component of preventive health measure strategies to mitigate the spread of respiratory illnesses. In this study five groups of masks were investigated that are of particular relevance to the SARS-CoV-2 pandemic: re-usable, fabric two-layer and multi-layer masks, disposable procedure/surgical masks, KN95 and N95 filtering facepiece respirators. Experimental work focussed on the particle penetration through mask materials as a function of particle diameter, and the total inward leakage protection performance of the mask system. Geometric mean fabric protection factors varied from 1.78 to 144.5 for the fabric two-layer and KN95 materials, corresponding to overall filtration efficiencies of 43.8% and 99.3% using a flow rate of 17 L/min, equivalent to a breathing expiration rate for a person in a sedentary or standing position conversing with another individual. Geometric mean total inward leakage protection factors for the 2-layer, multi-layer and procedure masks were <2.3, while 6.2 was achieved for the KN95 masks. The highest values were measured for the N95 group at 165.7. Mask performance is dominated by face seal leakage. Despite the additional filtering layers added to cloth masks, and the higher filtration efficiency of the materials used in disposable procedure and KN95 masks, the total inward leakage protection factor was only marginally improved. N95 FFRs were the only mask group investigated that provided not only high filtration efficiency but high total inward leakage protection, and remain the best option to protect individuals from exposure to aerosol in high risk settings. The Mask Quality Factor and total inward leakage performance are very useful to determine the best options for masking. However, it is highly recommended that testing is undertaken on prospective products, or guidance is sought from impartial authorities, to confirm they meet any implied standards.

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“…The COVID-19 pandemic revitalized the need to use different methodologies to disinfect surfaces and material potentially contaminated with SARS-CoV-2 [20], with reported claims that UV-C irradiation is a rapid and cost-effective solution for PPE disinfection [57,58]. Numerous studies have described the use of UV-C irradiation to inactivate SARS-CoV-2 [44,59,60]. For example, a UV-C irradiance of 3.7 mJ/cm 2 was sufficient to reduce more than three logs SARS-CoV-2 replication [41], while 16.9 mJ/cm 2 resulted in complete viral inactivation in aqueous suspension [41].…”

Section: Discussionmentioning

confidence: 99%

“…Most studies have tested unaltered and smooth FFR coupons, undisturbed by seams, strap attachments, or other common geometric features proper of any regular face mask [17,20,30]. Some studies have assessed the impact of multiple rounds of UVGI on pressure drop and particle-filtration efficiency [20], as well as multiple reuses or extended FFR wear on fit and filtration [59]; however, they have not evaluated disinfection efficacy. This work highlights the fact that due to the multiple cracks and crevices of FFRs, UV-C disinfection may not be a reliable method for pathogen inactivation on such materials.…”

Section: Discussionmentioning

confidence: 99%

Ultraviolet-C Irradiation, Heat, and Storage as Potential Methods of Inactivating SARS-CoV-2 and Bacterial Pathogens on Filtering Facepiece Respirators

et al. 2022

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The arrival of SARS-CoV-2 to Aotearoa/New Zealand in February 2020 triggered a massive response at multiple levels. Procurement and sustainability of medical supplies to hospitals and clinics during the then upcoming COVID-19 pandemic was one of the top priorities. Continuing access to new personal protective equipment (PPE) was not guaranteed; thus, disinfecting and reusing PPE was considered as a potential alternative. Here, we describe part of a local program intended to test and implement a system to disinfect PPE for potential reuse in New Zealand. We used filtering facepiece respirator (FFR) coupons inoculated with SARS-CoV-2 or clinically relevant multidrug-resistant pathogens (Acinetobacter baumannii Ab5075, methicillin-resistant Staphylococcus aureus USA300 LAC and cystic-fibrosis isolate Pseudomonas aeruginosa LESB58), to evaluate the potential use of ultraviolet-C germicidal irradiation (UV-C) or dry heat treatment to disinfect PPE. An applied UV-C dose of 1000 mJ/cm2 was sufficient to completely inactivate high doses of SARS-CoV-2; however, irregularities in the FFR coupons hindered the efficacy of UV-C to fully inactivate the virus, even at higher UV-C doses (2000 mJ/cm2). Conversely, incubating contaminated FFR coupons at 65 °C for 30 min or 70 °C for 15 min, was sufficient to block SARS-CoV-2 replication, even in the presence of mucin or a soil load (mimicking salivary or respiratory secretions, respectively). Dry heat (90 min at 75 °C to 80 °C) effectively killed 106 planktonic bacteria; however, even extending the incubation time up to two hours at 80 °C did not completely kill bacteria when grown in colony biofilms. Importantly, we also showed that FFR material can harbor replication-competent SARS-CoV-2 for up to 35 days at room temperature in the presence of a soil load. We are currently using these findings to optimize and establish a robust process for decontaminating, reusing, and reducing wastage of PPE in New Zealand.

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The impact of extreme reuse and extended wear conditions on protection provided by a surgical-style N95 filtering facepiece respirator

Cited by 6 publications

References 21 publications

Vapourized hydrogen peroxide decontamination in a hospital setting inactivates SARS-CoV-2 and HCoV-229E without compromising filtration efficiency of unexpired N95 respirators

Vapourized hydrogen peroxide decontamination in a hospital setting inactivates SARS-CoV-2 and HCoV-229E without compromising filtration efficiency of unexpired N95 respirators

The protective performance of reusable cloth face masks, disposable procedure masks, KN95 masks and N95 respirators: Filtration and total inward leakage

Ultraviolet-C Irradiation, Heat, and Storage as Potential Methods of Inactivating SARS-CoV-2 and Bacterial Pathogens on Filtering Facepiece Respirators

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