What is the difference between helium and carbon dioxide

These results suggested that helium may be a better inert or extinguishment agent on both a mass and a mole bases at microgravity even though CO2 is much better on a mole bases at earth gravity, and these are relevant to studies of fire safety in manned spacecraft, particularly the International Space Station that uses CO2 fire extinguishers. CO2 may not be as effective as an extinguishing agent at microgravity as it is at earth gravity in some conditions because of the differences in spread mechanisms between the two cases.

In particular, the difference between conduction-dominated heat transport to the fuel bed at earth gravity and radiation-dominated heat transport at microgravity indicates that radiatively-inert diluent such as helium could be preferable in microgravity applications. Helium may be a superior fire suppression agent at microgravity on several bases.

First, helium is more effective than CO2 on a mole basis thus pressure times storage volume basis at microgravity, meaning that the size and weight of storage bottles would be smaller for the same fire-fighting capability. Second; helium is much more effective on a mass basis by about 11 times at microgravity.

Third; helium has no physiological activity, unlike CO2 that affects human respiration. Fourth, as compared to N2 or CO2, is not very soluble in water and thus has fewer tendencies to cause bloodstream bubble formation following rapid spacecraft cabin depressurization.

Document ID. Document Type. Son, Youngjin University of Southern California. Ronney, Paul D. University of Southern California. Date Acquired. Month on month, the gas world website is the market-leading news portal for the global industrial gas sector, growing at an unprecedented rate and keeping its readers at the forefront of breaking news, insightful analysis and must-see features across the industry.

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