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Dissipation of Oxygen From Outward Leak of Closed Circuit Breathing Device



Kathryn M. Butler, Rodney A. Bryant, J G. Kovac


Closed circuit breathing devices recycle exhaled air after scrubbing carbon dioxide and adding make-up oxygen from a tank of pure oxygen. Use of this equipment allows first responders to work for up to four hours without swapping out cylinders. Firefighting situations in which these devices would be useful include tunnels, mines, and environments contaminated with biological or chemical toxins. A risk perceived by firefighters entering environments containing open flame and high radiant heat is the possibility of fire ignition in the vicinity of the respirator caused by the outward leakage of oxygen around the facepiece.This paper presents the progress on a computational fluid dynamics (CFD) study of oxygen dissipation into the environment surrounding a respirator facepiece. Actual heads and masks have been scanned into a 3D data set for entry into the CFD software, providing a physical boundary for the problem to be solved. Leak geometries representing an imperfect seal are defined. Oxygen concentration fields and flow streamlines will be determined for multiple leak geometries and for both normal and high stress breathing patterns.
Proceedings Title
Proceedings| Challenges in Protecting Frist Responders| 2005
Conference Dates
October 16-18, 2005
Conference Title
Advance Personal Protective Equipment Conference


closed circuit breathing devices, respirator leaks, respirators


Butler, K. , Bryant, R. and Kovac, J. (2005), Dissipation of Oxygen From Outward Leak of Closed Circuit Breathing Device, Proceedings| Challenges in Protecting Frist Responders| 2005, [online], (Accessed June 22, 2024)


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Created October 18, 2005, Updated February 19, 2017