Here’s our chief nurse’s design for a mask that would block airborne particles

Update: We have received numerous calls and emails from people around the country who want to see instructions for making the N95 replacement mask designed by University Health System’s chief nurse executive Tommye Austin. 

We are sharing this design with the understanding it should only be used for non-commercial purposes, and we cannot guarantee that others using this design will have a mask as effective as the one created by Austin. Here’s how she sourced special materials, developed her design and verified her mask’s effectiveness.


For the past month University Health System’s Tommye Austin, senior vice president and chief nurse executive, has kept a pair of scissors and small stacks of fabric samples next to her desk. They’re among the tools she has used to design a highly effective mask that will be available to protect healthcare employees if San Antonio sees a flood of COVID-19 patients.

“I just want my staff to be safe and I want anyone who is taking care of these patients to be safe,” said Austin as she explained why she began designing a replacement for the N95 masks traditionally worn by medical teams treating contagious patients.

Austin said she sprang into action when the U.S. Centers for Disease Control announced that healthcare workers caring for COVID-19 patients should cover their faces with bandanas or scarves if N95s weren’t available.

“Our nurses were up in arms. And I was alarmed as well,” she said. But instead of getting mad, she decided to get busy.

She bought some air conditioner filters from a local hardware store and began sandwiching pieces of the filters between layers of surgical draping. After experimenting with the components and adding a piece of metal that creates a snug fit across the bridge of the nose, Austin had a design that’s ready for prime time.

Southwest Research Institute, SwRI, tested the filtration effectiveness of about two dozen mask prototypes provided by Austin and University Health System. With consideration for the design, the methods of testing and effectiveness of the materials, University Health System is reproducing masks based on a prototype that removed 96.5% of airborne particles when tested.

Austin said a local alterations shop has produced 600 or her masks so far. Plans call for completing 6,500 more.

University Health System doesn’t have a shortage of its commercially-made N95s now, but if COVID-19 depletes their availability in San Antonio, the Health System will have an inventory of effective replacement masks ready to be worn. For the masks to be used beyond this coronavirus emergency they would need the approval of the National Institute of Occupational Safety and Health.

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