In this guest blog post Ania Mitros, Ph.D. discusses the laboratory testing data and science behind her preferred fabric combination for masks: two layers of ~65 gsm (gram/m²) spunbond nonwoven polypropylene (NWPP) plus one layer of ~130 gsm woven cotton. Her recommendation comes after reading dozens of scientific publications on the subject and investing thousands […]
Fabric Mask Material Testing Results! ASTM 2100 and F3502
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 […]
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 […]
Research Highlights: NWPP Filtration Efficiency from Long et al 2020
This post is the first in a series of “Research Highlights” where we discuss select data and research from the literature in the context of community mask making efforts. In this post, we take a look at the filtration and breathability data for nonwoven polypropylene (NWPP) mask materials presented in: Long KD, Woodburn EV, Berg […]
Fluid Resistance: Mask Material Test Results
New test results show that upcycled spunbond nonwoven polypropylene (NWPP) mask materials can provide high-level (ASTM Level 2) fluid resistance. MakerMask has supported the use of spunbond NWPP in homemade mask designs because of its unique combination of breathability and hydrophobicity, or water resistance. Thanks to community contributions, we were able to put the fluid […]
Mask Fabrics: Introduction to Fibers and Fabrics
How Do I Choose Fabrics for Masks for COVID-19? Since March, it seems like there has been a constant barrage of conflicting information about which fabrics are the best for masks for COVID-19. We’ve put together this crash course on mask fabrics to provide some of the fundamental concepts in fabrics and how they are relevant for our collective mask making efforts.
3 Easy DIY Mask Tests
In an ideal world, the safety and efficacy of all of the fabrics and materials used in handmade masks for COVID-19 would be tested using the same standards and facilities used by researchers and large manufacturers. Unfortunately, very few people have access to these resources. In this post we provide instructions for three easy DIY […]
WHO Guidance on Face Masks Changes
Surprising New Guidance from the WHO The WHO guidance on face masks for COVID-19 has changed to include the recommendation that the general public use fabric masks in public settings where physical distancing can’t be achieved and provides specific guidance on mask layers and materials. According to the World Health Organization (WHO), the ideal fabric […]
