Staymates, M.
(2020),
Flow visualization of an N95 respirator with and without an exhalation valve., Physics of Fluids
(Accessed September 17, 2025)
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Flow visualization of an N95 respirator with and without an exhalation valve.
Published
Author(s)
Abstract
This work demonstrates the qualitative fluid flow characteristics of a standard N95 respirator with and without an exhalation valve. Schlieren imaging was used to compare an adult male breathing through an N95 mask with and without a valve. Additionally, strategic lighting of fog droplets was used with a mannequin head to visualize the penetration of droplets through both masks. The mannequin exhaled with a realistic flow rate and velocity that matched an adult male. Additionally, the penetration of fog droplets was also visualized with a custom system that seals each respirator onto the end of a flow tube. Results of all these qualitative experiments suggest that N95 respirators with exhalation valves are not appropriate as a source control strategy for reducing the proliferation of infectious diseases that spread via respiratory droplets.Citation
Physics of Fluids
Pub Type
Journals
Keywords
COVID-19, fluid flow, flow visualization, mask, face covering, schlieren imaging, N95
Citation
Issues
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Created November 10, 2020, Updated November 3, 2022