A reusable, locally manufactured, half- face respirator provides better protection than fitted disposable N95 masks: development and quantitative fit-testing comparison

Abstract

\n The COVID-19 pandemic has led to persistent supply shortages of respiratory protective equipment in many jurisdictions. Reusable industrial respirators have been proposed and deployed as an alternative, but also face severe supply limitations. In addition, industrial respirators do not filter the user’s expired breath, a major limitation in health care settings where bidirectional protection is required. We present the development and quantitative testing of a reusable silicone respirator that can be locally manufactured using low-cost desktop infrastructure. Using standardized quantitative fit-testing (QNFT including resting and activity components according to CSA Z94.4-18) in a cohort of 41 healthcare workers (HCWs), we compared the performance of the mask to the individually-fitted disposable N95 masks that the HCWs had been assigned by our institution. Overall QNFT pass rates for disposable N95 respirators were 58.5% vs. 100% for the reusable mask. For a production run of 1000 masks, unit cost is approximately $25 CAD in materials and 35 minutes in labor per mask. The device requires further testing to assess flow resistance, carbon dioxide rebreathing, and full conformance with technical standards required for regulatory approval.