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Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering

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 respirator with and without a valve. The schlieren imaging technique showed the flow of wa...

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Detalles Bibliográficos
Autor principal: Staymates, Matthew
Formato: Online Artículo Texto
Lenguaje:English
Publicado: AIP Publishing LLC 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7684679/
https://www.ncbi.nlm.nih.gov/pubmed/33244212
http://dx.doi.org/10.1063/5.0031996
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author Staymates, Matthew
author_facet Staymates, Matthew
author_sort Staymates, Matthew
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description 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 respirator with and without a valve. The schlieren imaging technique showed the flow of warm air passing through these respirators but did not provide information about droplet penetration. For this, 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. 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 these qualitative experiments show that an N95 respirator without an exhalation valve is effective at blocking most droplets from penetrating through the mask material. Results also 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.
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spelling pubmed-76846792020-11-24 Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering Staymates, Matthew Phys Fluids (1994) Letters 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 respirator with and without a valve. The schlieren imaging technique showed the flow of warm air passing through these respirators but did not provide information about droplet penetration. For this, 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. 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 these qualitative experiments show that an N95 respirator without an exhalation valve is effective at blocking most droplets from penetrating through the mask material. Results also 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. AIP Publishing LLC 2020-11-01 /pmc/articles/PMC7684679/ /pubmed/33244212 http://dx.doi.org/10.1063/5.0031996 Text en © 2020 Author(s). 1070-6631/2020/32(11)/111703/5/$0.00 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Letters
Staymates, Matthew
Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
title Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
title_full Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
title_fullStr Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
title_full_unstemmed Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
title_short Flow visualization of an N95 respirator with and without an exhalation valve using schlieren imaging and light scattering
title_sort flow visualization of an n95 respirator with and without an exhalation valve using schlieren imaging and light scattering
topic Letters
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7684679/
https://www.ncbi.nlm.nih.gov/pubmed/33244212
http://dx.doi.org/10.1063/5.0031996
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