Using E-Beam to sterilize respirators
Tuesday November 08, 2022 from 13:30 to 15:00
Moon
Presenter

Aaron Neighbour, United States

Quality Assurance Manager

Quality Management

Nutek Bravo

Abstract

Using E-beam to Sterilize N95 Respirators, without Filter Degradation, on an Industrial Scale to Ensure that the Unacceptable Shortages of 2020 Never Happens Again for Healthcare Workers

Aaron Neighbour3.

1University of California San Francisco (UCSF), San Francisco, CA, United States; 2California Department of Public Heath (CDPH), Sacramento, CA, United States; 3Quality Management, Nutek Bravo, Hayward, CA, United States

In an attempt to combat the COVID19 shortage of filtering facepiece respirators (FFR's), many national labs and universities began research into using commercial irradiation methods to sterilize these masks for potential reuse by frontline workers. While the experimentally treated FFR's appeared to be mechanically intact after treatment—including the straps, nose clip, and face-seal coating—NIOSH NaCl testing revealed that the filtration efficiency of the FFR's had been reduced to an approximate range of 40-70%. The conclusion of these organizations was that ionizing radiation could not be used in a traditional way, as such methods significantly, adversely affected the electrostatic (ES) properties of filter, lowering the filtration efficiency beyond acceptable limits in all cases. FFR's like the N95 or FFP2 rely on a combination of mechanical and ES filtration for their high efficacy while remaining easy enough for human wearers to force air through the media under normal breathing conditions. The most penetrating particle sizes (which viruses like SARS-CoV-2 are included) that present challenges to these FFR's mechanical filters are handled by the ES filter; unfortunately, post-irradiation mask filtration data (published by IAEA) looked similar to mechanical-only data.

Nutek Bravo, working with suppliers at UCSF and CDPH, developed a novel sterilization process to dose used/infectious FFR's in bulk quantities without significantly degrading the filtration efficiency of any FFR (maintaining 90-93%). This allowed for full pathogenic inactivation and safe reuse by either original or new wearers. This solution that we optimized went through numerous iterations over the coarse of months; the resulting process has shown to be repeatable, affordable, and scalable.

 


Lectures by Aaron Neighbour

When Session Talk Title Room
Tue-08
13:30 - 15:00
RadSter-3: Product qualification Using E-Beam to sterilize respirators Moon

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