[Q] Breathable air pressure

[Moontanman]

I've been searching google for this info but I can't seem to find any info. what is the high limit for air pressure humans can live and breath in? I know humans can breath a few atmospheres because scuba equipment works down to at last 120 feet, that should be about 4 atmospheres or 60 psi. Can humans breath under more pressure with out being poisoned by the air? How much more? Is 10 atmospheres too much ?

[Janus]

The toxicity of oxygen depends on its "partial pressure". That is the fraction of the total atmospheric pressure accounted for by the oxygen. At normal air mixtures it reaches toxicity at 8 atm, but you could increase this pressure by decreasing the amount of oxygen by percentage in the air mixture, and thus lowering its partial pressure.

[modest]

Also, nitrogen becomes toxic at roughly the same pressure resulting in nitrogen narcosis. Using less oxygen (proportionately) and substituting helium and hydrogen for nitrogen, it looks like the human record in a dive chamber is about 700 meters. That’s about 69 atmospheres (almost the surface pressure on Venus). At that pressure high pressure nervous syndrome becomes a problem setting what looks like a pretty firm upper limit on the safe pressure at which humans can survive.

 

Also, "barotrauma" or "dysbarism" might be helpful in a google search.

 

~modest

 

EDIT:

 

Technology: Dry run for deepest dive - 28 November 1992 - New Scientist