Is it possible the decontamination and reuse of filtering face piece respirator (FFR) N95?

Alessandra Ninci indicated 14.03.2020
Carmelo De Maria 14.03.2020

it is possible to decontaminate FFRs with temperature treatments without damaging the masks, according to there three papers: (1) Viscusi, D. J. et al. (2011). Impact of three biological decontamination methods on filtering facepiece respirator fit, odor, comfort, and donning ease. Journal of occupational and environmental hygiene, 8(7), 426-436. (2) Heimbuch, B. K., et al. (2011). A pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets. American journal of infection control, 39(1), e1-e9. (3) Lore, M. B., et al. (2012). Effectiveness of three decontamination treatments against influenza virus applied to filtering facepiece respirators. Annals of occupational hygiene, 56(1), 92-101. (Edited)

14.03.2020
Carmelo De Maria 14.03.2020

In particular, it was demonstrated that warm moist heat sterilization at 65°C for 30 minutes provided a 4-log reduction of viable H1N1 virus (the one caused the swine flu, as called by the public media)

14.03.2020
Florinda Coro 14.03.2020

Great! Right now when there's a DPI shortage, it might be a more than useful approach!

14.03.2020

Looking at the published papers the great advantage is also that none of the decontamination methods affects the shape of the mask and therefore the fit on the face, fundamental to ensure the safety of the operator, so this approach seems very promising!

14.03.2020
Carmelo De Maria 14.03.2020

A sort of guideline can be found here https://docs.google.com/document/d/1IFO-kDexQaV0tO12iUjqRCB5YY0NMz_GyTAkebxl6NI/edit?usp=sharing (Edited)

14.03.2020
Carmelo De Maria 14.03.2020

Do not forget to take into consideration the indications of CDC https://www.cdc.gov/niosh/topics/hcwcontrols/recommendedguidanceextuse.html https://www.cdc.gov/niosh/npptl/pdfs/ElastomericPAPR-Healthcare-508.pdf

14.03.2020
Joana Costa 14.03.2020

I would like to bring up the fact that, regardless of the method that you choose to decontaminate the FFR, it is also extremely important to develop standard operation procedures (SOPs) to do it. In a study (that you can find here: https://www.sciencedirect.com/science/article/pii/S0196655315000899) on disinfection of reusable elastomeric respirators by health care workers, the authors verified that health care workers following manufacturers' instructions made multiple errors on the procedure, while health care workers following an adequate SOP did not. This case illustrates that not only is important to develop new solutions but also to show the users how to properly apply them.

14.03.2020

How about ozone treatments?

25.03.2020

Dear All, Assuming that this epidemic and the emergency situation will go on for months and that consequently the scarcity of personal protective equipment (such as facemasks) must be addressed not only by increasing production volumes, but also through reuse, I think this topic is extremely important. I also think that, to reduce the rate of infection, correct guidelines and tools for the sterilization and reuse of facemasks should be extended to the widest possible audience: not only medical health workers, but also clerks, couriers, employees in direct contact with the public and so on. To achieve this, an open source design and rigorous procedures could represent the best solution to reach the widest possible audience in the shortest possible time. Unfortunately practices that are not only incorrect but also harmful for the reuse of facemasks are spreading. Studying the scientific literature, I am evaluating three different possible approaches to reach this goal: the use of heat (as described by Carmelo de Maria), the use of germicidal UV-C lamps and the use of ozone. These different approaches have different effectiveness, produce a different degradation of materials (in particular plastics) and involve different risks for the health of users (in particular UV-C lamps and ozone). It must be considered that there are different types of masks on the market and the chosen approach must work adequately with all devices. I am studying this topic from an exclusively engineering point of view, with the aim of finding a simple and effective DIY solution. However, medical and biological considerations are indispensable.

02.04.2020
Carmelo De Maria 02.04.2020

Completely agree with the comment of Simone. Regarding the possibility to sterilize mask using UV: the sterilization with UV is not indicated for porous materials, given the limited penetration of the UV radiation. The masks are made of fabric, a porous material by definition

02.04.2020
Tinashe Johnson 11.04.2020

The Batelle decontamination system has U.S. Food and Drug Administration's Emergency Use Authorization (EUA) https://www.battelle.org/inb/battelle-critical-care-decontamination-system-for-covid19

11.04.2020