A team working at Sandia National Laboratories created what it says is a faster and better way to test personal protective equipment (PPE).
In short, they want to model devices to fit “the human form and human behavior,” according to a press release from Sandia National Laboratories.
Sandia saw a surge in demand for testing PPE equipment in March 2020 due to the coronavirus pandemic. At the time, companies were trying to make new masks, ensure imported masks were of sufficient quality, and coming up with ways to clean and reuse single-use PPE, if necessary.
“Whether using in-house or commercial filter test systems, we found the testing process was very time-consuming and not as efficient as it could be,” Michael Omana, an aerosol scientist at Sandia, said.
Engineers Todd Barrick and Brad Salzbrenner were on the team looking to find better solutions. They wanted to find ways to test respirators quickly, beyond just testing the filtration system and without damaging the equipment.
Typically, testing PPE equipment means “attaching a mask to a flat plate inside a box, using hot wax or putty, and then introducing a test aerosol to measure penetration levels,” according to the release.
To do this in a way that receives certification from the National Institute for Occupational Safety, labs must test 20 masks of the same type. Sandia notes that this is time-consuming and caused testing backlogs. Additionally, the process never considered other mask use factors.
“All you are doing is testing the filter media itself,” Barrick explained in the release. “It doesn’t test geometry, how the respirator fits on a face, how it’s moved on and off multiple times, how the straps perform, how the nose bridge performs, how the mask can wear over time.”
Also, given the worldwide PPE shortage, frontline workers resued single-use respirators, and there was no standard testing method for mask reuse.
“I think there were a lot of lessons learned with everyone suddenly looking at what the industry standards were,” Omana said.
The team at Sandia responded by creating a human face model it could load into a commercial filter test system.
“We wanted quicker testing and to look at more features, like how does the mask fit on a face,” Salzbrenner said. “We used 3D printing capabilities to make it more pliable, like skin.”
When someone affixed the mask to the form, the tester can apply pressure to give a tight seal and then introduce aerosol.
However, Sandia notes the current testing standards never consider how an actual person may wear their mask and how that alters the situation. Therefore, it created a version that tests using a molded human head.
Once the mask goes on the head mold, the head goes in an airtight box that goes in the machine for testing. The lab thinks this will give a “more realistic picture of mask performance,” according to the release.
The mechanical engineers on the team, understanding no standard testing for PPE use exists, aimed to solve that problem.
“We developed the chamber version to automate donning and doffing (the putting on and taking off of an item) to test respirator function over time, a predominant factor in wear on a mask,” Salzbrenner said. “It also mimics how a mask is set on the face and shows you any gaps that air and particles can get past.”
The team said people will use this in addition to other developed testing models, which represent an advance in PPE testing globally.
“I call it holistic testing,” Omana said. “It takes into account all of the aspects of the mask. Aerosols are like electricity and take the path of least resistance. Even if the filter media is doing great, if another subcomponent is failing, the PPE can be rendered useless. Current testing standards do not quantitatively test PPE in a real-use capacity. This emulates the real-world use of PPE.”
The team has received $100,000 in funding from Sandia’s Technology Maturation Program to keep working on this new testing approach. The team wants to license the science to a company that can do it commercially as a part of Sandia’s tech transfer initiative.
Sandia notes that the lab made this innovation during one of the worst pandemics in human history. It also notes that the company likes to tackle the world’s problems.
“Without the diverse capability of people at Sandia, a project like this would not have happened,” Salzbrenner said. “If you look at the background of each of the people on this team, everyone comes from a different discipline or walk of life. It was a combination of all these people who made these things happen.”
