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Scuba Forum / General / June 2005SCUBA tank at high altitude?
This is a physics question. Say you were in an airplane at 40,000 feet and lost cabin pressure. Would a SCUBA tank be of any help? Could you breathe higher pressure air in a lower pressure environment? Would the 3000 psi SCUBA tank already have exploded? I believe that pilots at high altitudes, in unpressureized airplanes, just breathe a higher concentration of oxygen at ambient pressure. Would a high pressure SCUBA tank be of any value at high altitudes? Thanks for your help. > This is a physics question. > > Say you were in an airplane at 40,000 feet and lost cabin pressure. ok. > Would a SCUBA tank be of any help? SCUBA is an acronym (as you may know) for self contained underwater breathing apparatus. The apparatus itself is of little benefit at altitude. What one breaths via that apparatus (in this senario) is of consequence however. > Could you breathe higher pressure air in a lower pressure environment? Yes to a degree, however, the second stage of a SCUBA regulator delivers gas at ambient pressure therefore the inspired PO2 (partial pressure of oxygen) would be the same. The end result is therefore the same, with or without the SCBA (self contained breathing apparatus). > Would the 3000 psi SCUBA tank already have exploded? Due to a drop in ambient pressure to 40000 feet? Not possible. > I believe that pilots at high altitudes, in unpressureized airplanes, > just breathe a higher concentration of oxygen at ambient pressure. Correct. The PO2 is therefore increased for said pilot simply because the FiO2 (fraction of inspired oxygen) is increased. > Would a high pressure SCUBA tank be of any value at high altitudes? Not if the cylinder contained air only. If the cylinder contained a higher FO2 (fraction of oxygen), above 21% for example it would be of benefit. > Thanks for your help. Denada. -- Randy F. Milak ~You say I'm a bitch like it's a bad thing?~ >> Thanks for your help. > > Denada. I cringe when I see Scott write this all the time, but I expect better from you, señor. It's "de nada". Two words. Literally means "of nothing". We don't say "ofnothing" after all. End of rant. Yourwelcome. Now how long would a 2 cf Spare Air Nitrox last at 40,000 cf assuming you could smuggle it past the X-rays? > >> Thanks for your help. > > > > Denada. > > I cringe when I see Scott write this all the time, but I expect better from > you, señor. Aim low, reach your goals, avoid disappointment. > It's "de nada". Two words. Literally means "of nothing". We don't say > "ofnothing" after all. It means "you are welcome". What kind of Californian are you? Most of you Califormexicans speak spanish; english is a second langage. > End of rant. > Yourwelcome. You'rewelcome and Denada! > Now how long would a 2 cf Spare Air Nitrox last at 40,000 cf assuming you > could smuggle it past the X-rays? What's your RMV? -- Randy F. Milak ~Is it time for your medication or mine?~ >> Now how long would a 2 cf Spare Air Nitrox last at 40,000 cf assuming you >> could smuggle it past the X-rays? > > What's your RMV? Pretty darn high when the plane's about to crash. > This is a physics question. Not really. > Say you were in an airplane at 40,000 feet and lost cabin pressure. Would > a SCUBA tank be of any help? Could you breathe higher pressure air in a [quoted text clipped - 3 lines] > pressure. > Would a high pressure SCUBA tank be of any value at high altitudes? Yes and no. A scuba tank is just a container. The usefulness, in different situations, depend on what is in it. At the moment, I have one that is full of oxygen, several with mixes ranging from 32% to 40% oxygen, one with 50% oxygen and several with air. Any and all of them would provide something better to breath than what is available at 40,000 feet. The problem, however, is not whether or not a tank full of gas would help, but rather, how you would get it aboard the plane. Cylinders of compressed gas are definitely on the disallowed list. To transport a scuba tank legally, you have to drain it very close to empty. Some airlines have required that the tank be completely empty and the valve removed. An empty tank isn't much help. Lee >This is a physics question. > >Say you were in an airplane at 40,000 feet and lost cabin pressure. >Would a SCUBA tank be of any help? Could you breathe higher pressure >air in a lower pressure environment? Would the 3000 psi SCUBA tank >already have exploded? No to all questions. >I believe that pilots at high altitudes, in unpressureized airplanes, >just breathe a higher concentration of oxygen at ambient pressure. At altitude, I breath 100% O2. At 8000 meters, 100% O2 is barely sufficient to allow climbing. OTOH, Reinhold Messner successfully soloed Everest without oxygen, so it can be done, but then again, he's a freak of nature. I've done Gasherbrum 2 without oxygen, but it was a painful slog from about 7500 meters. >Would a high pressure SCUBA tank be of any value at high altitudes? Read Lee's post for actually Usenet useful infomation. >Thanks for your help.  Signaturedillon Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. > This is a physics question. > [quoted text clipped - 8 lines] > > Thanks for your help. I agree with Randy. It would be of no help if it contained pressurized air-- the PO2 would be the same as cabin air, just as the PO2 is higher underwater it would be lower in the cabin. Adam |
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