Reusable, N95 alternative face mask developed by a collaborative team hits production
By MIT Media Lab
When nations across the globe began facing the growing danger of the Covid-19 pandemic, it became evident that Personal Protective Equipment (PPE) would be in short supply. In March 2020, the United States Department of Health and Human Services (HHS) admitted that the country struggles to meet even a fraction of the demand for respirator face masks.
In response to this serious need, a diverse team consisting of engineers, designers, clinicians, technicians, molders, among other entities, concentrated their intellects and efforts towards the rapid deployment and mass manufacture of an “open hardware, reusable, sterilizable, modular, and filter-media agnostic face mask that aims to hit the N95 efficacy criteria.” The project coalesced from a collaboration through Helpful Engineering, a volunteer-run nonprofit dedicated to aiding the fight against Covid-19, though Open Standard Respirator currently spearheads the project organization.
Co-leads of the project include MIT Media Lab postdoctoral researcher Matt Carney, Aaron Cantrell (Principal Designer at Cofab Design), and Philip Brown (PhD, Wake Forest Baptist Health). An interview with Carney on the front porch of his home in Somerville, MA, sheds light on specific aspects of the creation process.
Instead of “reinvent[ing] the wheel,” Carney says, the team has focused on addressing current supply deficiencies with a design that can better utilize available resources. For example, the face piece of the mask is constructed to be compatible with either LSR or TPE manufacturing processes, so traditional machines can deploy the masks quickly, but also take advantage of the mechanical and sterilizable properties of silicone. Additionally, the modular design requires less filter material and generates less medical waste, while keeping people safe and being cost-effective.
The mask itself, like the N95 mask, aims to be a tight-fitting, elastomeric respirator with a comfortable seal around the face, and includes a replaceable bi-directional filter. However, governmental safety regulations provide an extra layer of complexity to the situation — as Carney says, “those safety rules are actually very hard to hit.”
The National Institute for Occupational Safety and Health (NIOSH) and the American Society of Testing and Materials (ASTM) specify a handful of tests that must be satisfied to ensure the safety of this type of PPE. In addition to testing the filter media, there are two tests that directly relate to the combination of the face mask’s mechanical design and the specific filter material: the residual CO2 test and the particle filtration efficiency test at specific volume flow-rates (and resulting air-velocities). Both of these metrics can only be evaluated with analytical equipment and directly affect the safety of the mask.
The team’s early advantages included rapid iteration with access to 3D-printed silicone (technology developed at MIT), technical testing of their prototypes at every stage of development, and intense focus on the user experience. From the first week they were sending parts to test on equipment similar to that specified by NIOSH and ASTM, particularly to assess the safety of the mask, which encompasses three main criteria: 1) inhale/exhale pressure drop or breathing resistance, 2) re-breathing of residual CO2, and 3) filter efficiency. “As you exhale, you breathe out a bunch of CO2, and if there’s dead space between your face and the mask, when you re-inhale that you’re re-inhaling CO2, so you’re not getting as much oxygen as you would expect…[and] as the filter area shrinks, the air and particle velocities increase, making the filter media less effective at protecting you,” Carney states.
Medical workers have provided feedback on the design of these prototypes; three hospitals and three county emergency medical services are currently evaluating them. Bryan Gallimore, Battalion Chief of the Quality Assurance/Training Division at Forsyth County Emergency Services (Winston-Salem, NC), says that “this project has been really, really good for us…I’ve had multiple users wear them and run through some of the standard procedures [and] job requirements that we would have with the other PPE that typically would go hand-in-hand with an N95.”
Starting in early June 2020, the “Open Standard Respirator, Model 1” has entered large scale production phases in the US, Portugal, and expanding to Colombia and Brazil. From the very beginning, as Carney notes, the project’s collaborative nature embodies the spirit of the MIT Media Lab. “It’s leveraging what we’re good at, at the Media Lab. This desire to jump in and think a little differently about things, and to build up a team to actually make things happen.”
This post was originally published on the Media Lab website.