neon half time tables
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Dean810
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I have heard of Neon as a dive gas before. I would be interested in learning what you find out. I guess the main advantage of it over Helium is in communications, as it doesn't distort the voice.
Charlie99
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Check out the program by Departure .... http://www.diverssupport.com/Departure.htm
It handles mixed gases, including neon.
If you look at how helium is handled in most programs, you will find that halftimes are assume to be proportional to the square root of molecular weights. See "Grahams Law".
N2 = 28. He = 4. SQR(7) = 2.6 ---- in other words, helium halftimes are those of nitrogen halftimes but divided by 2.6.
If you were to apply the same logic to Neon, avg molecular weight of 20.2, then you would divide the N2 compartment halftimes by sqr(28/20.2) = 1.18
Try www.thedecostop.com as a place more likely to have good info on mixed gases;.
It handles mixed gases, including neon.
If you look at how helium is handled in most programs, you will find that halftimes are assume to be proportional to the square root of molecular weights. See "Grahams Law".
N2 = 28. He = 4. SQR(7) = 2.6 ---- in other words, helium halftimes are those of nitrogen halftimes but divided by 2.6.
If you were to apply the same logic to Neon, avg molecular weight of 20.2, then you would divide the N2 compartment halftimes by sqr(28/20.2) = 1.18
Try www.thedecostop.com as a place more likely to have good info on mixed gases;.
Dean810
Contributor
If that is true, I would like to know how that would work. I know it is a fairly dense gas. I'm not sure how that would reduce decompression. I would love to hear more comment on this.
Charlie99
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It will reduce decompression for some dives, but not others. The big problem with neon is that it has relatively high solubility --- so the tissues will absorb a lot of gas.
Helium on the other hand, has low solubility ---- the total amount of gas dissolved into the tissues has a lower limit at saturation. For short dives, more helium will be absorbed than would neon or nitrogen and you hit the "ndl" faster. For long dives, the total helium in the body will be less than it would be if nitrogen was used, and therefore for long dives, helium has faster decompression.
For helium, the dividing line between where helium goes from worse than nitrox to better is right around or just past what would be the air or nitrox NDL. This is something that seems to get missed by people that assume that, because helium results in faster deco on a 4 hour 200' dive, that helium is better from a decompression standpoint on a 100' 20 minute dive on EAN32 vs 30/30.
Helium on the other hand, has low solubility ---- the total amount of gas dissolved into the tissues has a lower limit at saturation. For short dives, more helium will be absorbed than would neon or nitrogen and you hit the "ndl" faster. For long dives, the total helium in the body will be less than it would be if nitrogen was used, and therefore for long dives, helium has faster decompression.
For helium, the dividing line between where helium goes from worse than nitrox to better is right around or just past what would be the air or nitrox NDL. This is something that seems to get missed by people that assume that, because helium results in faster deco on a 4 hour 200' dive, that helium is better from a decompression standpoint on a 100' 20 minute dive on EAN32 vs 30/30.
Dean810
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Does Neon have a narcotic effect at depth?
Dr Deco
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Hello shov6:
Neon
Neon has been investigated as a diving gas but only for deep diving (500 fsw) by military or commercial divers. The reports were by Bill Hamilton PhD and came out of his laboratory in 1974 at Ocean Systems when I was just a novice barophysiologist employed there. These reports were prepared for the US Navy who sponsored them, and I do not know where they can be obtained anymore.
During the tests, the gas was not found to be narcotic as nitrogen but somewhat more than helium, was easily breathed, had good thermal characteristics, and did not distort the voice as badly as helium.
The deco programs listed by a responder look interesting, but I am not personally acquainted with the results they might yield.
Decompression Properties
Some references to neon with regard to diffusion and so on are listed below.
The halftimes used are really more or less dependent on the diving being performed. Surface supplied diving requires longer halftimes. The real question for all dive calculations is the amount of the ascent that can be performed for any halftime. This can only be found from trials in a laboratory.
Dr Deco :doctor:
References
Bennett PB, Hayward AJ. Relative decompression sickness hazards in rats of neon and other inert gases. Aerosp Med. 1968 Mar;39(3):301-2.
Van Liew HD, Passke M. Permeation of neon, nitrogen and sulfur hexafluoride through walls of
subcutaneous gas pockets in rats. SAM-TR-70-5. Tech Rep SAM-TR. 1970 Jan;:240-2.
Hamilton RW Jr, Doebbler GF, Schreiner HR. Biological evaluation of various spacecraft cabin atmospheres. I.Space Life Sci. 1970 Dec;2(3):307-34
Graves DJ, Idicula J, Lambertsen CJ, Quinn JA. Bubble formation resulting from counterdiffusion supersaturation: a possible explanation for isobaric inert gas 'urticaria' and vertigo. Phys Med Biol. 1973 Mar;18(2):256-64.
Powell MR, Doebbler GF, Hamilton RW Jr. Serum enzyme level changes in pigs following decompression trauma. .Aerosp Med. 1974 May;45(5):519-24.
Powell MR. Doppler ultrasound monitoring of venous gas bubbles in pigs following
decompression with air, helium, or neon. Aerosp Med. 1974 May;45(5):505-8..
Lambertsen CJ, Idicula J. A new gas lesion syndrome in man, induced by "isobaric gas counterdiffusion". J Appl Physiol. 1975 Sep;39(3):434-43.
Hlastala MP, Van Liew HD. Absorption of in vivo inert gas bubbles. Respir Physiol. 1975 Jul;24(2):147-58.
Vorosmarti J, Bradley ME, Anthonisen NR. The effects of increased gas density on pulmonary mechanics. Undersea Biomed Res. 1975 Mar;2(1):1-10..
Lambertsen CJ, Gelfand R, Peterson R, Strauss R, Wright WB, Dickson JG Jr,
Puglia C, Hamilton RW Jr. Human tolerance to He, Ne, and N2 at respiratory gas densities equivalent to He-O2 breathing at depths to 1200, 2000, 3000, 4000, and 5000 feet of sea water
(predictive studies III). Aviat Space Environ Med. 1977 Sep;48(9):843-53..
D'Aoust BG, Stayton L, Smith LS. Separation of basic parameters of decompression using fingerling salmon. Undersea Biomed Res. 1980 Sep;7(3):199-209.
Neon
Neon has been investigated as a diving gas but only for deep diving (500 fsw) by military or commercial divers. The reports were by Bill Hamilton PhD and came out of his laboratory in 1974 at Ocean Systems when I was just a novice barophysiologist employed there. These reports were prepared for the US Navy who sponsored them, and I do not know where they can be obtained anymore.
During the tests, the gas was not found to be narcotic as nitrogen but somewhat more than helium, was easily breathed, had good thermal characteristics, and did not distort the voice as badly as helium.
The deco programs listed by a responder look interesting, but I am not personally acquainted with the results they might yield.
Decompression Properties
Some references to neon with regard to diffusion and so on are listed below.
The halftimes used are really more or less dependent on the diving being performed. Surface supplied diving requires longer halftimes. The real question for all dive calculations is the amount of the ascent that can be performed for any halftime. This can only be found from trials in a laboratory.
Dr Deco :doctor:
References
Bennett PB, Hayward AJ. Relative decompression sickness hazards in rats of neon and other inert gases. Aerosp Med. 1968 Mar;39(3):301-2.
Van Liew HD, Passke M. Permeation of neon, nitrogen and sulfur hexafluoride through walls of
subcutaneous gas pockets in rats. SAM-TR-70-5. Tech Rep SAM-TR. 1970 Jan;:240-2.
Hamilton RW Jr, Doebbler GF, Schreiner HR. Biological evaluation of various spacecraft cabin atmospheres. I.Space Life Sci. 1970 Dec;2(3):307-34
Graves DJ, Idicula J, Lambertsen CJ, Quinn JA. Bubble formation resulting from counterdiffusion supersaturation: a possible explanation for isobaric inert gas 'urticaria' and vertigo. Phys Med Biol. 1973 Mar;18(2):256-64.
Powell MR, Doebbler GF, Hamilton RW Jr. Serum enzyme level changes in pigs following decompression trauma. .Aerosp Med. 1974 May;45(5):519-24.
Powell MR. Doppler ultrasound monitoring of venous gas bubbles in pigs following
decompression with air, helium, or neon. Aerosp Med. 1974 May;45(5):505-8..
Lambertsen CJ, Idicula J. A new gas lesion syndrome in man, induced by "isobaric gas counterdiffusion". J Appl Physiol. 1975 Sep;39(3):434-43.
Hlastala MP, Van Liew HD. Absorption of in vivo inert gas bubbles. Respir Physiol. 1975 Jul;24(2):147-58.
Vorosmarti J, Bradley ME, Anthonisen NR. The effects of increased gas density on pulmonary mechanics. Undersea Biomed Res. 1975 Mar;2(1):1-10..
Lambertsen CJ, Gelfand R, Peterson R, Strauss R, Wright WB, Dickson JG Jr,
Puglia C, Hamilton RW Jr. Human tolerance to He, Ne, and N2 at respiratory gas densities equivalent to He-O2 breathing at depths to 1200, 2000, 3000, 4000, and 5000 feet of sea water
(predictive studies III). Aviat Space Environ Med. 1977 Sep;48(9):843-53..
D'Aoust BG, Stayton L, Smith LS. Separation of basic parameters of decompression using fingerling salmon. Undersea Biomed Res. 1980 Sep;7(3):199-209.
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