Hydrox (breathing gas)
Encyclopedia
Hydrox, a gas mixture of hydrogen
and oxygen
, is used as a breathing gas
in very deep diving
. It allows divers to descend several hundred metres.
Precautions are necessary when using hydrox, since mixtures containing more than a few percent of either oxygen or 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
.
(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.
Zetterström showed that hydrogen was perfectly usable to great depths. Sadly, 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. 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).
(HPNS), commonly occurring during very deep dives.
These studies scored a resounding success with a simulated dive to 701 metres (2,299.9 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".
has evaluated the use of bacterial flora
to speed decompression from hydrox diving.
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, is used as a breathing gas
Breathing gas
Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...
in very deep diving
Deep diving
The meaning of the term deep diving is a form of technical diving. It is defined by the level of the diver's diver training, diving equipment, breathing gas, and surface support:...
. It allows divers to descend several hundred metres.
Precautions are necessary when using hydrox, since mixtures containing more than a few percent of either oxygen or hydrogen are explosive if ignited. Hydrogen is the lightest gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
(half the weight of helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
) but still has a narcotic potential
Nitrogen narcosis
Narcosis while diving , is a reversible alteration in consciousness that occurs while scuba diving at depth. The Greek word ναρκωσις is derived from narke, "temporary decline or loss of senses and movement, numbness", a term used by Homer and Hippocrates...
and may cause hydrogen narcosis
Hydrogen narcosis
Hydrogen narcosis is the psychotropic state induced by breathing hydrogen at high pressures. Hydrogen narcosis produces symptoms such as hallucinations, disorientation, and confusion, which are similar to hallucinogenic drugs. It can be experienced by deep-sea divers who dive to below sea level...
.
History
Although the first reported use of hydrogen seems to be by Antoine LavoisierAntoine Lavoisier
Antoine-Laurent de Lavoisier , the "father of modern chemistry", was a French nobleman prominent in the histories of chemistry and biology...
(1743–1794), who had guinea pigs breathe it, the actual first uses of this gas in diving
Diving
Diving is the sport of jumping or falling into water from a platform or springboard, sometimes while performing acrobatics. Diving is an internationally-recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.Diving is one...
are usually attributed to trials by the Swedish engineer, Arne Zetterström
Arne Zetterström
Arne Zetterström is best known for his research with the breathing mixture hydrox for the Swedish Navy.Zetterström first described the use of hydrogen as a breathing gas in 1943...
in 1945.
Zetterström showed that hydrogen was perfectly usable to great depths. Sadly, 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
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
and by the Compagnie maritime d'expertises
Compagnie maritime d'expertises
COMEX is a company specializing in engineering and deep diving operations, created in November 1961 and run ever since then by Henri Germain Delauze....
(Comex), initially during their Hydra I and Hydra II experiments, in 1968 and 1969. 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
Hydreliox
Hydreliox is an exotic breathing gas mixture of helium, oxygen and hydrogen.It is used primarily for research and scientific deep diving, usually below . Below this depth, extended breathing of heliox gas mixtures may cause high pressure nervous syndrome . Two gas mixtures exist that attempt to...
(hydrogen-helium-oxygen).
Use
Hydrox may be used to combat high pressure nervous syndromeHigh pressure nervous syndrome
High-pressure nervous syndrome is a neurological and physiological diving disorder that results when a commercial diver or scuba diver descends below about while breathing a helium–oxygen mixture. The effects depend on the rate of descent and the depth...
(HPNS), commonly occurring during very deep dives.
These studies scored a resounding success with a simulated dive to 701 metres (2,299.9 ft), by Theo Mavrostomos on 20 November 1990 at Toulon
Toulon
Toulon is a town in southern France and a large military harbor on the Mediterranean coast, with a major French naval base. Located in the Provence-Alpes-Côte-d'Azur region, Toulon is the capital of the Var department in the former province of Provence....
, during the COMEX Hydra X decompression chamber experiments. This dive made him "the deepest diver in the world".
Biochemical decompression
The United States NavyUnited States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
has evaluated the use of bacterial flora
Gut flora
Gut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....
to speed decompression from hydrox diving.