Breathing Easy: Testing Cloth Masks for the People, By the People
Researchers at North Carolina State University Investigate Efficiency and Fit Assessment of Face Masks for Public Use
The dedicated team at North Carolina State University's Textile Protection and Comfort Center has taken it upon themselves to ensure that the cloth masks used by the public are both effective and reliable against the spread of the coronavirus. After noticing a gap in the market for consistent and specific testing methods for homemade masks, the researchers saw an opportunity to put their expertise in protective equipment testing for firefighters and first responders to good use.
"When we saw people making cloth masks and realizing there were no standardized testing methods for them, we started brainstorming about ways to test them more effectively," explains Bryan Ormond, assistant professor of textile engineering and chemistry in the NC State Wilson College of Textiles.
The Centers for Disease Control and Prevention recommends the general public wear multi-layer cloth masks to prevent the transmission of SARS-CoV-2, the virus that causes COVID-19, through respiratory droplets as well as to reduce inhalation of these droplets by the wearer.
To delve into the testing strategies employed by the NC State team, The Abstract caught up with Ormond for a frank conversation about their work on testing cloth masks for the public.
The Abstract: Describe some of the tests you're running on face masks worn by the general public?
Ormond: During the pandemic, we've been working remotely from home, with some in the lab, to develop a couple of tests that provide a screening level for testing filtration. Our primary concern is whether or not the material effectively filters the air.
We've fabricated a simple cell that enables us to pass air through the fabric, count the particles on either side, and estimate the filtration efficiency. We've recently added an aerosol generator to provide a consistent level of particles at a consistent size, as it can be difficult to control ambient air conditions from day to day.
In another approach, we look at the entire product to gauge the impact of the mask's overall design. Cloth face coverings are not flat pieces of material – they have openings around the face, the nose, and a particular fit.
We utilize an animatronic breathing head form, which we can control, to test masks simultaneously for their filtration efficiency and fit.
TA: In what ways do cloth face masks safeguard people?
Ormond: When addressing any hazard, the first line of defense involves administrative and engineering controls. Generally, this refers to maintaining a 6-foot distance, washing hands, and staying at home.
Protective equipment, including respirators and face coverings, serve as the last line of defense in any situation, not just respiratory protection.
Additionally, it's essential to recognize that a mask is just one of many tools in the public health arsenal. Each individual wearing a mask helps contribute to overall protection by reducing the spread of the virus a little bit.
TA: Are there standardized guidelines for cloth face masks?
Ormond: Currently, there is no certification process or specification for cloth face coverings for the general public. The American Association of Textile Chemists and Colorists (AATCC) did come out with a design specification or guideline for constructing them.
The Subcommittee on Respiratory Protection of ASTM International has assembled a task group, comprising experts from across the country, to develop a specification for cloth face coverings. This task involves determining design and performance requirements for certification. We also need to choose the ideal test methods that reflect the mask's performance in everyday use situations.
TA: What factors should one look for in a face mask?
Ormond: Filtration efficiency, breathability, and fit are crucial factors when evaluating a face mask. Filtration efficiency refers to how many particles a particular material effectively blocks. Breathability is essential for maintaining comfort; filtration efficiency and breathability often have an inverse relationship. Lastly, proper fitting is crucial to prevent air from escaping through gaps, which reduce the mask's effectiveness.
TA: What are your ultimate goals for face mask testing?
Ormond: Ideally, we'd like to create a rating system that makes it easier for shoppers to compare different masks. If a specification is in place, consumers will know that each mask has been tested and meets agreed-upon performance standards.
Additionally, we hope to establish a measurement or rating system for breathability to aid consumers in making informed decisions.
The ongoing evolution of testing standards and research into more effective protective mask materials aims to create a healthier and safer world for all.
- The team at North Carolina State University's Textile Protection and Comfort Center is conducting research on materials used for cloth masks, with a goal to ensure they are effective against the spread of the coronavirus.
- During the pandemic, the researchers have been developing and refining tests for filtration efficiency, breathability, and fit of homemade masks, using both a simple cell and an animatronic breathing head form.
- The NC State team aims to create a rating system for face masks, based on standardized guidelines, to help shoppers compare different mask options and make informed decisions about health-and-wellness products.
- In the future, the team hopes to establish a measurement or rating system for breathability, a factor that is crucial for maintaining comfort and reducing the inverse relationship between filtration efficiency and breathability.
- The ongoing face mask testing and research into more effective protective materials for textiles is part of a broader effort in science and engineering to improve medical-conditions and fitness-and-exercise equipment, as well as other technological innovations.
- The NC State team's work on testing cloth masks for the public not only supports health-and-wellness, but also contributes to the news and information landscape by providing reliable scientific data on the performance of cloth masks.
