GIS Story: How a last-minute collaboration helped a healthcare network safely put reusable surgical masks to use
Every day since the outbreak of the COVID-19 pandemic, frontline healthcare workers in New York State have risked their own health while caring for patients potentially infected with the new coronavirus disease. One of the greatest modes of transmission for infection that nurses, doctors, and other caregivers face is through exposure to bodily fluids. To mitigate this threat, hospitals have put in place new policies for increased use of surgical masks by staff at all levels. But this comes as the coronavirus pandemic has severely disrupted global supply chains and increased demand for medical products, making the commercial disposable masks hospitals typically use scarce.
In the hardest hit U.S. state, amid a lockdown on all non-essential economic activity, some manufacturers chose to help hospitals get the medical-grade masks and other personal protective equipment (PPE) they need by reopening and shifting their production lines. Hickey Freeman, a high-end clothing maker based in Rochester, New York, is one such company. (It is not the first time the company has risen to the occasion during a moment of national need—it produced military uniforms for the United States armed forces during the Second World War.)
Multiple-use surgical masks
Hickey Freeman’s senior vice president of technical design, Jeffrey Diduch, was contacted by Dr. Ralph Pennino, senior vice president of Specialty Medical and Surgery Group at Rochester Regional Health (RRH), a healthcare system operating across Greater Rochester with more than 16,000 employees. Pennino had reached out to a number of New York manufacturers to find a local supply solution to meet RRH’s demand for surgical masks—more than 25,000 a day.
RRH wanted to invest in a sustainable solution that would ensure a steady, renewable supply of surgical masks, so Pennino sought out cloth varieties that could be washed, sterilized, and reused. This, in part, reflects the organization’s wider resource-efficiency strategy. RRH has been recognized by Practice Greenhealth for its exceptional initiatives within sustainability. Reusable masks would secure RRH a reliable stock even as the availability of conventional masks wavered. They could potentially be cleaned and sterilized, and then distributed as needed across RRH’s nearly 250 medical centers.
Revised FDA standards during the pandemic
A reusable surgical mask needs to meet the same standards that are expected of a single-use one. But washing and sterilization can damage the integrity of a mask’s material, making it ineffective.
Surgical masks are regulated by the U.S. Food and Drug Administration (FDA) to ensure that they are safe and effective. However, in response to the surge in demand for masks caused by the COVID-19 crisis, the FDA eased its regulations in April 2020. The agency published a revised enforcement policy that defined surgical masks as “class II devices that cover the user’s nose and mouth and provide a physical barrier to fluids and particulate materials and are tested for flammability and biocompatibility.”
The updated policy required that surgical mask used for medical purposes must still conform to liquid-barrier performance testing consistent with ASTM F1862, a test titled “Standard Test Method for Resistance of Medical Face Masks to Penetration by Synthetic Blood (Horizontal Projection of Fixed Volume at a Known Velocity).” They also had to comply with either Class I or II flammability requirements set out in 16 CFR 1610 (U.S. Code of Federal Regulations). Appropriate labeling was also expected.
Diduch was accustomed to tackling many design challenges, but designing for the medical environment, which meant taking into account details like how deeply blood saturated different fabrics (liquid-barrier penetration), was entirely new. His first task was to understand the critical features of commercial surgical masks, then to find practical ways for achieving them using Hickey Freeman’s existing equipment and processes, originally intended for making luxury clothing. After ample research and many iterations, he and his team were able to create three prototypes. Each was made with a different material that can be washed or sterilized: spunbond meltblown spunbond (SMS) fabric, Kimberley-Clark™ N-95 surgical wrap, and cotton.
These were sent to a testing laboratory recommended by the Centers for Disease Control and Prevention (CDC). The lab was heavily backed up due to the crisis, so it took three weeks before Diduch learned that the prototypes passed.
Two other manufacturers along with Hickey Freeman sent mask designs to RRH, but none had been tested for use after multiple washes and sterilizations. Before making any decisions on behalf of RRH, Pennino had to better understand how each prototype would perform before and after cycles of washing and sterilization before hospital staff could safely wear them. To gain insight into this, he contacted the director of sustainability at RRH, Dr. Michael Waller, who in turn reached out to the Center of Excellence in Advance and Sustainable Manufacturing (COE-ASM) at RIT.
Validating a washable, reusable surgical mask
RRH had little time to spare as COVID-19 infections rose—Pennino and his team needed accurate data immediately so they could confidently move forward with one or more of the surgical masks. The results would also give two of the manufacturers practical confidence to pursue official FDA certification.
Pennino met with Mark Walluk, assistant director of COE-ASM, to lay out a test to assess the efficacy of each of the prototypes over the course of multiple washings. Walluk worked with staff engineers at COE-ASM to identify the methods and procedures that most closely aligned to what an FDA approval process involve, which are based on the ASTM and CFR standards.
The masks were washed and sterilized a number of times before they were delivered to COE-ASM’s laboratories on RIT’s campus. Nine types of masks were tested. In addition to the prototypes supplied by manufacturers, two were commercial disposable masks that RRH had used prior to the crisis. These served as benchmarks.
Testing for liquid-barrier penetration
ASTM F1862 outlines how a liquid-barrier penetration test needs to be designed and conducted. This includes specifications for equipment, required measurements, and a recipe for synthetic blood.
Liquid-barrier testing equipment, which included an actuated pneumatic valve, were loaned to the COE-ASM team by RRH. This was fitted into a fixture that was designed and 3D-printed by staff at RIT’s Golisano Institute for Sustainability (GIS) using dimensions set out in the standard. Once hooked up to an air compressor at a steady pressure, the assembly was ready to spray synthetic blood at a single mask secured in place at a prescribed distance. The pressure and velocity of the blood hitting the specimen was adjustable in order to meet the standard’s specifications.
The standard includes a formula for synthetic blood that behaves like real blood. The mixture had to be precise in order to mimic the surface tension and specific gravity of blood, which are essential to simulating how blood projects from a capillary through air and saturates material. ASTM F1862 identifies three common blood-pressure levels in the human body (80, 120, and 160 millimeters of mercury). These correspond to three levels of velocity at which blood, theoretically, leaves a vessel (450, 550, and 635 centimeters per second, respectively). Commercial masks are rated against these to indicate fluid-penetration tolerance.
When we breathe through a mask, it adds moisture and heat to the material. To recreate this unique use condition following the standard, a humidity and temperature chamber was used.
Once all the equipment and accessory materials were set up, Walluk and his team began testing prototypes. Synthetic blood was sprayed at a randomly selected mask from the set provided by RRH in two-milliliter spurts through a three-sixteenths-of-an-inch hole in the fixture holding the mask. Given the urgency of the project, several deviations from the standard were needed, such as the number of masks that were tested at random.
Testing for flammability
The next phase of the project was to test the flammability of the different materials used in the prototypes following the specifications laid out in 16 CFR Part 1610. Although this standard is officially recommended by the FDA, it offers limited guidance on how to practically set up a test. The COE-ASM team was able to fill in the gaps by referring to ASTM D1230-17, another standard that provides, among other details, dimensions for a test fixture.
Five COE-ASM staff members, Michael Leaty, Dominic Maiola, Chris Piggott, Kristin Schipull, and Bram Valure, constructed the unique structure according to the instructions provided in ASTM D1230-17. A local sheet-metal shop fabricated a custom hold for the fabric samples to be clamped into.
Ahead of testing, a section of material was taken from each prototype that measured two-by-six inches. Each sample was then conditioned in an industrial oven before being placed in a desiccator—which dries it. The treated sample was then placed into the test fixture.
Inside, a flame that was just over half of an inch long was applied to the material for about a second (1.0 ±0.1, per the standard). A high-speed video camera was used to measure the behavior over the one-second interval and capture the burn-time.
The flammability testing was completed in the Bal Dixit Laboratory for Advanced Materials and Fire Protection Research at GIS. The lab was especially designed for quantifying the fire, flammability, and mechanical properties of advanced materials by GIS in collaboration with Newtex, a manufacturer of high-temperature fabrics and engineered systems for thermal management and fire protection. (Funding for the lab is made possible through a two-million-dollar gift on behalf of Bal Dixit, chairman of the board at Newtex and a 1974 alumnus of RIT’s Saunders College of Business.)
Thanks to the tests, Pennino and Waller gained critical information about the safety and effectiveness of the different mask prototypes they were considering. Two failed the liquid-barrier penetration test, though the COE-ASM team identified a simple modification that could bring one of these up to standard. All of the masks passed the flammability tests.
“We had results from the CDC-recommended lab that our mask would function correctly for its first use. What COE-ASM helped us to understand was what would happen after repeated washings,” Diduch noted after the tests were completed.
Going into to the testing with COE-ASM, Diduch already had results confirming that Hickey Freeman’s masks met FDA standards for their initial use. The tests at RIT were unique because they simulated mask performance after multiple wash and sterilization cycles; the CDC-recommended lab’s test did not.
Hickey Freeman’s three different designs performed well in the flammability and liquid-barrier tests. Several of its materials also passed the tests after repeated wash cycles, suggesting that continued testing at a certified laboratory after multiple washes would be worthwhile. The test results gave Hickey Freeman the early confidence Diduch needed to scale up production to supply RRH and other healthcare providers. At the time of writing, the company had manufactured close to 150,000 masks at its Rochester facility. It was also working with the Canadian province of Quebec on a similar effort to support the fight against COVID-19 through its Montreal operation.
A crisis-ready model
The number of COVID-19 patients that are being treated at RRH began to stabilize in early May as efforts to “flatten the curve” in the Rochester region began to bear fruit. Yet, the possibility of new waves of infections remains, especially as New York State considers steps for reopening businesses and other key parts of its economy.
Collaboration formed the bedrock of this project, linking RRH and three innovative New York State manufacturers to COE-ASM’s engineering expertise and industry-grade facilities. It is one example of the many cross-sector partnerships that have been made through the state’s strategic efforts to sustain economic growth in the aftermath of the 2009 recession. Now, in the midst of what may be an even graver crisis than the Great Recession, this strategy will continue to be essential to supplying healthcare providers with PPE and other critical resources that traditional supply chains are unable to deliver.
“I absolutely loved the way the group came together to address specific needs,” Diduch noted on his experience of working with COE-ASM and RRH jointly.
Waller, who is also a 2016 graduate of RIT’s doctoral program in sustainability at GIS, echoed this sentiment. “It’s amazing to see the progress our organizations can make when working together in such a short time,” he said.
COE-ASM is a New York State Center of Excellence and is supported by Empire State Development’s Division of Science, Technology, and Innovation (NYSTAR)—the testing was completed at no cost to either RRH or the participating manufacturers.