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#1
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hi alt oxygen
Im just wondering why pure oxygen is used for high altitude flying
instead of regular air. I thought prolonged exposures to breathing pure oxygen can be harmfull as you can become oxygen dependant. |
#2
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"Arquebus257WeaMag" wrote in message m... Im just wondering why pure oxygen is used for high altitude flying instead of regular air. I thought prolonged exposures to breathing pure oxygen can be harmfull as you can become oxygen dependant. http://www.batnet.com/mfwright/hypoxia.html Hypoxia Hypoxia is a state of oxygen deficiency in the body which is sufficient to cause an impairment of function. Hypoxia is caused by the reduction in partial pressure of oxygen, inadequate oxygen transport, or the inability of the tissues to use oxygen. In brief, being drunk is kind of the same as being exposed to high altitude. In both cases, oxygen to your brain and muscles is reduced. |
#3
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Tarver Engineering wrote:
In brief, being drunk is kind of the same as being exposed to high altitude. In both cases, oxygen to your brain and muscles is reduced. Even briefer, being Tarver illustrates the results of chronic hypoxia. Rick |
#4
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"Rick" wrote in message hlink.net... Tarver Engineering wrote: In brief, being drunk is kind of the same as being exposed to high altitude. In both cases, oxygen to your brain and muscles is reduced. Even briefer, being Tarver illustrates the results of chronic hypoxia. "Rick" wrote in message link.net... Ah, memories come back ... in my old freight dog days I used to fly with an older guy who hated to waste fuel on pressurization while crossing the Rockies in Montana. His only complaint was that he had a hard time keeping his cigarettes lit when the MEA's were in the flight levels. chronic hypoxia Bwahahahahahahahaha |
#5
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Subject: hi alt oxygen
From: "Tarver Engineering" Date: 3/11/04 8:32 AM Pacific Standard Time Message-id: "Rick" wrote in message thlink.net... Tarver Engineering wrote: In brief, being drunk is kind of the same as being exposed to high altitude. In both cases, oxygen to your brain and muscles is reduced. Even briefer, being Tarver illustrates the results of chronic hypoxia. "Rick" wrote in message hlink.net... Ah, memories come back ... in my old freight dog days I used to fly with an older guy who hated to waste fuel on pressurization while crossing the Rockies in Montana. His only complaint was that he had a hard time keeping his cigarettes lit when the MEA's were in the flight levels. chronic hypoxia Bwahahahahahahahaha Actually you are right. Oxygen drunks were not uncommon (hic) Arthur Kramer 344th BG 494th BS England, France, Belgium, Holland, Germany Visit my WW II B-26 website at: http://www.coastcomp.com/artkramer |
#6
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"ArtKramr" wrote in message ... Subject: hi alt oxygen From: "Tarver Engineering" Date: 3/11/04 8:32 AM Pacific Standard Time Message-id: "Rick" wrote in message thlink.net... Tarver Engineering wrote: In brief, being drunk is kind of the same as being exposed to high altitude. In both cases, oxygen to your brain and muscles is reduced. Even briefer, being Tarver illustrates the results of chronic hypoxia. "Rick" wrote in message hlink.net... Ah, memories come back ... in my old freight dog days I used to fly with an older guy who hated to waste fuel on pressurization while crossing the Rockies in Montana. His only complaint was that he had a hard time keeping his cigarettes lit when the MEA's were in the flight levels. chronic hypoxia Bwahahahahahahahaha Actually you are right. Oxygen drunks were not uncommon (hic) I knew a few of those. |
#7
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You live off off something called the "partial pressure of oxygen" in the
medium you are breathing. As altitude increases, the partial pressure of oxygen in air decreases. Therefore, you must "enrich" the breathing medium with more oxygen in order to achieve the *same* partial pressure of oxygen that exists at lower altitudes. Two solutions: 1) increase the relative percentage of oxygen inht e medium, or 2) pressurize hte medium. 1) is much less expensive than 2). Steve Swartz (The partial pressure of oxygen is what gets the O2 across your lung tissue into your bloodstream. As total pressure decreases, the partial pressure of oxygen decreases. Eventually, as ambient pressure goes down, you would need to breathe pure *pressurized* [3.2 psi IIRC] oxygen in order to make up the deficit.) "Arquebus257WeaMag" wrote in message m... Im just wondering why pure oxygen is used for high altitude flying instead of regular air. I thought prolonged exposures to breathing pure oxygen can be harmfull as you can become oxygen dependant. |
#8
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Thank you for the information. Very interesting! On Wed, 10 Mar 2004 11:46:52 -0500, "Leslie Swartz" wrote: You live off off something called the "partial pressure of oxygen" in the medium you are breathing. As altitude increases, the partial pressure of oxygen in air decreases. Therefore, you must "enrich" the breathing medium with more oxygen in order to achieve the *same* partial pressure of oxygen that exists at lower altitudes. Two solutions: 1) increase the relative percentage of oxygen inht e medium, or 2) pressurize hte medium. 1) is much less expensive than 2). Steve Swartz (The partial pressure of oxygen is what gets the O2 across your lung tissue into your bloodstream. As total pressure decreases, the partial pressure of oxygen decreases. Eventually, as ambient pressure goes down, you would need to breathe pure *pressurized* [3.2 psi IIRC] oxygen in order to make up the deficit.) "Arquebus257WeaMag" wrote in message om... Im just wondering why pure oxygen is used for high altitude flying instead of regular air. I thought prolonged exposures to breathing pure oxygen can be harmfull as you can become oxygen dependant. all the best -- Dan Ford email: (requires authentication) see the Warbird's Forum at www.warbirdforum.com and the Piper Cub Forum at www.pipercubforum.com |
#9
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Here's some quick and dirty info on oxygen - normally about 1/5 of
'air'. So the 'partial pressure' is 1/5 of 29.92 inches/760 mm Hg equalling 152mm O2. The ambient air pressure drops by 1/2 every 18,000 feet (roughly). So at sea level you get 1/5 of 760mm; at 18,000 you get 1/5 of 380mm. At about 34000 you get the equivalent of sea level oxygen partial pressure breathing 100% oxygen. If you keep going on up pretty soon you reach a dangerously low level of partial pressure - that's at about 41,000. So modern diluter-demand O2 regulators start feeding you oxygen under pressure. Easy to inhale - you have to work to exhale. This gets worse as you keep going up. At 50,000 cabin pressure it is physically demanding to exhale and the mask has to be very tightly strapped on your face. Not to mention painful. Note that so far we don't have any 'cabin pressure' - air bled from the engine(s) to remedy the situation. Also as you keep climbing into areas of lesser pressure water boils at progrssively lower temperatures. At 63,000 ambient pressure water boils at 98.6F/37C - body temp. That means your lungs are now filled with water vapor and you can no longer absorb oxygen. Hence pressure cabins and pressure suits over 50,000 feet. Breathing pure oxygen for extended periods of time is a hassle. First, there is no water in Aviator's oxygen - can't take the chance of water freezing in the lines. Therefore every breath you're becoming more and more dehydrated. Second, oxygen can flood the inner ears (through the eustachian tubes) and late at night in bed that oxygen gets absorbed by the blood and you wake up with giant earaches. Third, if you're breathing pure O2 and pulling lots of G - the lower airsacs in your lungs tend to stick together because with pure O2 you're not breathing as deeply. Back on the ground when you take a deep breath it feels as if someone just knifed you. This is termed 'atelactasis'. Now, oxygen is used to keep pilots crew and passengers functioning at more or less an efficient level. Rule of thumb - O2 over 10,000 feet. There is a 'cheat' where one can got to 12 for 30 minutes. But the brain needs O2 to function properly. With hard training one can function adequately at higher altitudes. But even the best can screw up - read 'Into Thin Air'. FWIW I used to teach this stuff. Walt BJ |
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