Microfiber Cleaning Cloth Makes Best Face Covering, Says Biodefense Lab

Microfiber Cleaning Cloth Makes Best Face Covering, Says Biodefense Lab

BY SIMON VEAZEY April 29, 2020 Updated: May 6, 2020

The Pentagon’s bioweapons protection lab says that the best material for homemade face coverings is microfiber cleaning cloth.

The Combat Capabilities Development Command (CCDC) Chemical Biological Center is normally charged with the development of tactical masks and respiratory systems, along with equipment that can detect biological threats such as anthrax and smallpox.

Recently, the center has put aside its specialist equipment to test different materials for their suitability as face coverings for protection against COVID-19.

“The best readily available material to use in a homemade face covering is four-ply microfiber cloth which can be found in the cleaning section of most big box stores,” the Combat Capabilities Development Command (CCDC) Chemical Biological Center concluded in a statement, after it had tested more than 50 different materials.

“We knew that claims about masks and face coverings were exploding all over the internet, and we wanted to make sure that any decisions about materials these agencies make will be based on proven science,” said David Caretti, chief of the Center’s Chemical Biological Protection & Decontamination Division and leader of the team testing homemade face-covering materials.

The center tests by spraying a suspension of particles 0.2 to 0.3 microns in size at the material, and seeing how much gets through.

The center didn’t specify all of the materials it had tested but said that the most suitable was four-ply microfiber cloth, which can filter out more than 75 percent of particles. An N95 mask used by health care workers, by comparison, can filter out 90 percent of particles.

“Even a polyester bandanna can be reasonably effective if it is used in layers. It will filter out 40 percent of suspended particles,” the statement said.

“The challenge is to pick a material that effectively blocks the virus particles from going through the material while not being too hard to breathe through,” said Caretti. “If the resistance is too high, airflow will simply bypass the covering and go around the edges.”