Flow permeability and flow-induced deformations of medical face masks and mask materials

After more than a year of SARS-CoV-2 pandemic, the face mask has been recognized as the most effective and practical piece of personal protective equipment (PPE) used to minimize the virus spread. Although there have been numerous studies performed on the filtration efficiencies of different mask materials, little attention has been paid to the deformation of mask materials due to respiratory activities and how the fluid-structure interactions affect the mask fit and effectiveness. We study this performance of multiple mask materials by characterizing permeability and mechanical deformation, including the fit of the mask on the face. Several combinations of flow rates and velocities corresponding to various respiratory activities, such as breathing, sneezing, coughing, speaking, and exercising, are defined for people of different ages and genders. The deformation of several mask materials is recorded using a laser profilometer, and the permeability is calculated from a modified Darcy's Law using pressure drop measurements at various flow rate conditions.