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 […]
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 […]
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 […]
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 […]
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 […]
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.
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 […]
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 […]
This deep dive post looks into the “Big Four” criteria evaluated in preliminary assessments of community mask materials: material characteristics, breathability, water-repellence, and disinfection options. More specifically, we focus on nonwoven polypropylene (NWPP), which is commonly used in commercial face masks. Although ideal medical grade NWPP is not currently available for community use, NWPP is commonly available at different weights and grades for other household and/or commercial purposes, such as reusable grocery bags. Here we take a more in-depth look at the 4 preliminary criteria considered when evaluating potential sources of NWPP.
The MakerMask project team has reviewed extensive literature on the science and manufacturing of NIOSH-approved respirators. We selected a multi-layered design that balanced increased filtration capabilities with permeability for breathing. The spunbond non-woven polypropylene (NWPP) outer layers use the same type of material used in medical-grade commercial masks, providing water-resistance for blocking droplet transmission and mechanical filtration from the structure of the fibers.