Flow visualization of an N95 respirator with and without an exhalation valve.

Published

November 10, 2020

Author(s)

Matthew E. Staymates

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

Staymates, M. (2020), Flow visualization of an N95 respirator with and without an exhalation valve., Physics of Fluids (Accessed March 23, 2023)