A huge thank you to everyone that has contributed to our fabric mask material testing campaign! The results from the testing campaign are finally in. We tested two different 3-layer fabric combinations to establish baseline performance for fluid resistance, breathability, bacterial filtration efficiency (~3um particles), and submicron particle efficiency (~0.3um). These tests focused on two […]
Masks for COVID: Literature Highlights
In this post we share some of our favorite articles about mask science. Since the beginning of this pandemic over 6000 papers have been published on masks. For scientists and sewists alike, sorting through all this information can be daunting! We have gathered our top recommendations for those looking to join us in immersing themselves […]
Washing Fabric Masks: Knowns and Unknowns
Recently, we’ve been hearing a lot of questions about washing and reusing fabric masks. There are a wide range of “best practices” emerging from government organizations, sewist groups, and journalists. This post discusses cleaning of masks containing spunbond non-woven polypropylene (NWPP) layers, and clarifies some distinctions between washing and disinfection. Introduction First, a caveat — […]
New ASTM Standard for Face Coverings: ASTM F3502
Since February of 2020, we’ve been asking for standards for masks/face coverings used by our communities. Finally, the American Society for Testing and Materials (ASTM) has established a national standard for “Barrier Face Coverings” (ASTM F3502) that are neither medical masks according to ASTM F2100 standards nor respirators according to NIOSH standards. This new standard […]
Improving Mask Fit and Seal
As the pandemic progresses, more attention is being paid to incorporating design features that improve mask fit. To maximize the benefits of these design features, masks need to be put on (donned) and taken off (doffed) using techniques that people outside of the healthcare industries may not be as familiar with. In this post we […]
Mask Material Testing Plan
Update (February 12, 2021): Thanks to our generous community and a grant from Helpful Engineering, we exceeded our fundraising goal for mask testing! In addition to the originally planned fluid resistance, breathability, and bacterial filtration testing of our fabric combinations, we were able to add mask-level NaCl aerosol filtration tests to our campaign. Thank you […]
Common Approaches to Increasing Seam Strength
Mask Math/Science Vignette: Mask Straps According to the guidance released by the WHO in December mask straps should be designed to withstand at least 10 lbs of force ( 44.5 Newtons). The materials that most straps are constructed from (e.g., cotton straps and silicone bands) easily meet these requirements. However, we’ve seen a number of […]
WHO Fabric Mask Guidance – December Updates
On December 1, 2020, the World Health Organization (WHO) updated their guidance on fabric masks, “Mask Use in the Context of COVID-19 (December, 2020)”, including their “Updated Guidance on Non-Medical (Fabric) Masks” (p. 19-22). This post pulls out key quotes from the new WHO guidance, touching on their recommendations for layering, mask performance standards, and […]
Finding and Selecting Polypropylene for Washable Masks
In this post we discuss how we think about selecting spunbond nonwoven polypropylene (NWPP) fabrics for washable masks, where we have found spunbond NWPP, and why we’ve chosen Smart-Fab® Double-Thick for our next round of testing. Our Mission Our mission is to share information with the public about the best emerging mask science to help […]
Breathable Masks: Testing Results
Key result: Quantitative testing shows that fabric masks constructed from spunbond nonwoven polypropylene (NWPP) and/or quilting cotton are breathable and can satisfy NIOSH criteria for breathability. Ready for more testing? Visit our MakerMask Lab Testing Campaign for details. Introduction: Breathable Masks Breathing isn’t optional, and as COVID continues and mask wearing becomes commonplace, we are […]