physical risks of hydrogen?

**nigelh** · 19th November 2007, 08:20

Quote: (Originally Posted by Abbo)

The move to hydrogen seems to have been brought on largely because of the $ cost of Helium, but rebreathers don't waste much diluent and the $ is tanking. It was also caused because the US once had a near-monopoly on Helium, but that is no longer the case, as deposits are being exploited in the FSU.

I though I read that hydrogen was preferred for HPNS problem reductions but I don't bother to track things like that as they are so far out of my sphere so I can't give you a refference...

Sutty · 19th November 2007, 09:53

Quote: (Originally Posted by Genesis)

At mixtures containing over 4% O2 hydrogen can rapidly combine with that oxygen to form water.

(This is commonly called "an explosion" and is really bad if it happens in your breathing loop!)

I get enough water in my loop as it is so I think I'll skip this one!

jaap · 19th November 2007, 12:45

Quote: (Originally Posted by hirudin)

I read the Comex articles discussing the use of hydreliox and the physical effects the divers experienced on the dives, but it certainly doesn't seem like a good idea... and I don't like the idea of partially-hydrogenating my own body fat.

Guess I'm just interested in a discussion on the use of hydrogen and it's longer term effects.... just for yuks.

-Jesse-

Hi

Hydrogenation of unsaturated fats are usually processes that require somewhat elevated temperaures and a catalyst. So don't expect much to happen with the bodyfats of the hydrox/hydreliox-diver.

Hydrogen-mixes have been used in experimental diving and even for some working dives for over 60 years, by many nations and corporations. So I'm quite sure they did think about this potential side effect.

As a side note I think the rational for adding hydrogen into diving mixes have been a mix of the following:

Cost and avaliability. He was a strategic resource, like during WWII. So some could not get enough/afford a He-based deep diving program.
Low density, H2 is even better than He if you need to breath at extrem depths.
HPNS countermeasure, H2 is slightly narcotic so the idea is that a moderate narcosis level makes the diver less susceptible to HPNS

Of course Hydrogen is probably completely useless unless you are going very deep. Given that I have never heard of any diving program combining any significant fraction of H2 with more than ~4% O2 (risk of explosion).

PS
If you want to think about really funky stuff, look around for info on "chemical deco". That is using like H2 for diving combined with an in vivo (inside the diver) catalyst that decomposes the accumulated gas into water cutting the deco. There is also som really far off talk about using nitrogen fixating bacteria to cut deco from nitrogen mixes...or the use of methane breathing mix and decocutting bacteria...

Gene_Hobbs · 19th November 2007, 13:30

Quote: (Originally Posted by Abbo)

There's some interesting reading on "Hydrogen as a breathing gas" by RW Braur at
Rubicon Research Repository: Item 123456789/4862

Thanks Abbo! Always nice to see the repository being used! The full reference for the workshop is:

Brauer RW (ed). Hydrogen as a Diving Gas. 33rd Undersea and Hyperbaric Medical SocietyWorkshop. UHMS Publication Number 69(WS-HYD)3-1-87. Bethesda: Undersea and HyperbaricMedical Society; 1985; 336 pages. RRR ID: 4862

Note: The file is pretty big.

Quote: (Originally Posted by jaap)

If you want to think about really funky stuff, look around for info on "chemical deco". That is using like H2 for diving combined with an in vivo (inside the diver) catalyst that decomposes the accumulated gas into water cutting the deco. There is also som really far off talk about using nitrogen fixating bacteria to cut deco from nitrogen mixes...or the use of methane breathing mix and decocutting bacteria...

And... Most of that work was done at NMRI by Kayar and Fahlman.

Decompression sickness risk reduced by native intestinal flora in pigs after H2 dives.
Kayar and Fahlman. Undersea Hyperb Med. 2001 Summer;28(2):89-97.
RRR ID: 2373

MODULATION OF DECOMPRESSION SICKNESS RISK IN PIGS BY CAFFEINE ADMINISTRATION DURING H2 BIOCHEMICAL DECOMPRESSION.
Kayar et. al. 2001 (UHMS abstract)
RRR ID: 1027

DECOMPRESSION SICKNESS RISK CORRELATED WITH ACTIVITY OF H2-METABOLIZING MICROBES INJECTED IN PIGS PRIOR TO DIVES IN H2.
Fahlman et. al. 1999 (UHMS abstract)
RRR ID: 787

19th November 2007, 08:20	#11 (permalink)
nigelh New Member Current Rebreather/s: Inspiration Vision Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Mar 2005 Location: Brighton, Sussex, UK Posts: 821	Re: physical risks of hydrogen? Quote: (Originally Posted by Abbo) The move to hydrogen seems to have been brought on largely because of the $ cost of Helium, but rebreathers don't waste much diluent and the $ is tanking. It was also caused because the US once had a near-monopoly on Helium, but that is no longer the case, as deposits are being exploited in the FSU. I though I read that hydrogen was preferred for HPNS problem reductions but I don't bother to track things like that as they are so far out of my sphere so I can't give you a refference... __________________ nigelh
(Online)

19th November 2007, 09:53	#12 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 781	Re: physical risks of hydrogen? Quote: (Originally Posted by Genesis) At mixtures containing over 4% O2 hydrogen can rapidly combine with that oxygen to form water. (This is commonly called "an explosion" and is really bad if it happens in your breathing loop!) I get enough water in my loop as it is so I think I'll skip this one! __________________ Never forget that life is a finite resource.
(Offline)

19th November 2007, 12:45	#13 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 445	Re: physical risks of hydrogen? Quote: (Originally Posted by hirudin) I read the Comex articles discussing the use of hydreliox and the physical effects the divers experienced on the dives, but it certainly doesn't seem like a good idea... and I don't like the idea of partially-hydrogenating my own body fat. Guess I'm just interested in a discussion on the use of hydrogen and it's longer term effects.... just for yuks. -Jesse- Hi Hydrogenation of unsaturated fats are usually processes that require somewhat elevated temperaures and a catalyst. So don't expect much to happen with the bodyfats of the hydrox/hydreliox-diver. Hydrogen-mixes have been used in experimental diving and even for some working dives for over 60 years, by many nations and corporations. So I'm quite sure they did think about this potential side effect. As a side note I think the rational for adding hydrogen into diving mixes have been a mix of the following: Cost and avaliability. He was a strategic resource, like during WWII. So some could not get enough/afford a He-based deep diving program. Low density, H2 is even better than He if you need to breath at extrem depths. HPNS countermeasure, H2 is slightly narcotic so the idea is that a moderate narcosis level makes the diver less susceptible to HPNS Of course Hydrogen is probably completely useless unless you are going very deep. Given that I have never heard of any diving program combining any significant fraction of H2 with more than ~4% O2 (risk of explosion). PS If you want to think about really funky stuff, look around for info on "chemical deco". That is using like H2 for diving combined with an in vivo (inside the diver) catalyst that decomposes the accumulated gas into water cutting the deco. There is also som really far off talk about using nitrogen fixating bacteria to cut deco from nitrogen mixes...or the use of methane breathing mix and decocutting bacteria... __________________ My initials: JAAP Last edited by jaap : 19th November 2007 at 12:51.
(Offline)

19th November 2007, 13:30	#14 (permalink)
Gene_Hobbs Custom Title Allowed! Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Sep 2006 Location: Durham, NC, USA Posts: 117	Re: physical risks of hydrogen? Quote: (Originally Posted by Abbo) There's some interesting reading on "Hydrogen as a breathing gas" by RW Braur at Rubicon Research Repository: Item 123456789/4862 Thanks Abbo! Always nice to see the repository being used! The full reference for the workshop is: Brauer RW (ed). Hydrogen as a Diving Gas. 33rd Undersea and Hyperbaric Medical SocietyWorkshop. UHMS Publication Number 69(WS-HYD)3-1-87. Bethesda: Undersea and HyperbaricMedical Society; 1985; 336 pages. RRR ID: 4862 Note: The file is pretty big. Quote: (Originally Posted by jaap) If you want to think about really funky stuff, look around for info on "chemical deco". That is using like H2 for diving combined with an in vivo (inside the diver) catalyst that decomposes the accumulated gas into water cutting the deco. There is also som really far off talk about using nitrogen fixating bacteria to cut deco from nitrogen mixes...or the use of methane breathing mix and decocutting bacteria... And... Most of that work was done at NMRI by Kayar and Fahlman. Decompression sickness risk reduced by native intestinal flora in pigs after H2 dives. Kayar and Fahlman. Undersea Hyperb Med. 2001 Summer;28(2):89-97. RRR ID: 2373 MODULATION OF DECOMPRESSION SICKNESS RISK IN PIGS BY CAFFEINE ADMINISTRATION DURING H2 BIOCHEMICAL DECOMPRESSION. Kayar et. al. 2001 (UHMS abstract) RRR ID: 1027 DECOMPRESSION SICKNESS RISK CORRELATED WITH ACTIVITY OF H2-METABOLIZING MICROBES INJECTED IN PIGS PRIOR TO DIVES IN H2. Fahlman et. al. 1999 (UHMS abstract) RRR ID: 787 __________________ http://rubicon-foundation.org/ Home of the Rubicon Research Repository. For help getting started with the Repository, please visit our FAQ page. PLEASE support our work. "Oxygen is addictive and deadly. Everyone who uses it will eventually die" --RW Hamilton, PhD 1991
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