Hydrox (breathing gas)

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This article is about the breathing gas. For the cookie brand, see Hydrox.

Hydrox, a gas mixture of hydrogen and oxygen, was used as a breathing gas in very deep diving. It allows divers to descend several hundred metres.[1][2][3]

Precautions are necessary when using hydrox, since mixtures containing more than a few percent of both oxygen and hydrogen are explosive if ignited. Hydrogen is the lightest gas (half the weight of helium) but still has a narcotic potential and may cause hydrogen narcosis.[2][3]

History[edit]

Although the first reported use of hydrogen seems to be by Antoine Lavoisier (1743–1794), who had guinea pigs breathe it, the actual first uses of this gas in diving are usually attributed to trials by the Swedish engineer, Arne Zetterström in 1945.[3]

Zetterström showed that hydrogen was perfectly usable to great depths. Following a fault in using the surface equipment, he died during a demonstration dive. The study of hydrogen was not resumed until several years later by the United States Navy and by the Compagnie maritime d'expertises (Comex), initially during their Hydra I and Hydra II experiments, in 1968 and 1969.[4] Comex subsequently developed procedures allowing dives between 500 and 700 metres (1650 to 2300 feet) in depth, while breathing gas mixtures based on hydrogen, called hydrox (hydrogen-oxygen) or hydreliox (hydrogen-helium-oxygen).[1][5]

Use[edit]

Hydrox may be used to combat high pressure nervous syndrome (HPNS), commonly occurring during very deep dives.[6]

These studies scored a resounding success with a simulated dive to 701 metres (2,300 ft), by Theo Mavrostomos on 20 November 1990 at Toulon, during the COMEX Hydra X decompression chamber experiments. This dive made him "the deepest diver in the world".[7]

Biochemical decompression[edit]

The United States Navy has evaluated the use of bacterial flora to speed decompression from hydrox diving.[8][9][10]

See also[edit]

References[edit]

  1. ^ a b Fife, William P (1979). "The use of Non-Explosive mixtures of hydrogen and oxygen for diving". Texas A&M University Sea Grant. TAMU-SG-79-201. 
  2. ^ a b Brauer RW (ed). (1985). "Hydrogen as a Diving Gas.". 33rd Undersea and Hyperbaric Medical Society Workshop. (Undersea and Hyperbaric Medical Society) (UHMS Publication Number 69(WS–HYD)3–1–87): 336 pages. Retrieved 2008-09-15. 
  3. ^ a b c Ornhagen H (1984). "Hydrogen-Oxygen (Hydrox) breathing at 1.3 MPa". National Defence Research Institute. FOA Rapport C58015-H1. ISSN 0347-7665. 
  4. ^ Comex keeps up the High Pressure, Comex Magazine
  5. ^ Rostain, J. C.; M. C. Gardette-Chauffour; C. Lemaire; R. Naquet. (1988). "Effects of a H2-He-O2 mixture on the HPNS up to 450 msw". Undersea Biomed. Res. 15 (4): 257–70. ISSN 0093-5387. OCLC 2068005. PMID 3212843. Retrieved 2008-09-19. 
  6. ^ Hunger Jr, W. L.; P. B. Bennett. (1974). "The causes, mechanisms and prevention of the high pressure nervous syndrome". Undersea Biomed. Res. 1 (1): 1–28. ISSN 0093-5387. OCLC 2068005. PMID 4619860. Retrieved 2008-09-15. 
  7. ^ Lafay V, Barthelemy P, Comet B, Frances Y, Jammes Y (March 1995). "ECG changes during the experimental human dive HYDRA 10 (71 atm/7,200 kPa)". Undersea Hyperb Med 22 (1): 51–60. PMID 7742710. Retrieved 2008-09-15. 
  8. ^ Ball R (2001). "Biochemical decompression of hydrogen by naturally occurring bacterial flora in pigs: what are the implications for human hydrogen diving?". Undersea Hyperb Med 28 (2): 55–6. PMID 11908695. Retrieved 2008-09-15. 
  9. ^ Kayar SR, Fahlman A (2001). "Decompression sickness risk reduced by native intestinal flora in pigs after H2 dives". Undersea Hyperb Med 28 (2): 89–97. PMID 11908700. Retrieved 2008-09-15. 
  10. ^ Fahlman, A (2000). "On the Physiology of Hydrogen Diving and Its Implication for Hydrogen Biochemical Decompression". PhD Thesis. Carleton University, Ottawa, ON, Canada. Retrieved 2008-09-15. 

External links[edit]