Heliox

Heliox is a gas mixture which is primarily used in professional diving and technical diving as a breathing gas. Heliox was first used in 1939 in the rescue of survivors from the crashed submarine USS Squalus from about 82 meters depth.

Composition

Heliox usually consists of 79% helium and 21% oxygen (Oxygen ), or immersion depth of 7 m to 100 m of 88% helium and 12 % oxygen. Other ratios of helium and O2 are set depending on the planned depth. In order to reach a depth of 180 meters, 8.42% oxygen may only be present. As with an O2 partial pressure of about 1.6 bar oxygen toxicity can occur without Travelmix deep diving with heliox not possible. In addition, the time at this depth is limited to a maximum of 2 hours, but must be due to the Sauerstoffuhr or O2 - clock (also CNS O2 % ) can be shortened dramatically.

Benefits

• No Tiefenrausch with narcotic effect, since no nitrogen is included.
• Larger depths - theoretically up to 600 m - possible.

Disadvantages

• Helium is causing the High Pressure Nervous Syndrome (helium tremors )
• The high thermal conductivity of the helium from 0.1513 W / ( m · K) leads to the cooling of the lungs. The gas must be artificially heated.
• Excessive breathing resistance in great depth by the high density of air at depth. This effect is with any other inert gas but even more

Alternatives

As an alternative to Heliox Trimix can be mentioned, which contains oxygen and helium variable amounts of 20-44 % nitrogen. Hydrox is an alternative breathing gas mixture of hydrogen ( Hydrogenium ) and oxygen ( Oxygenium ), and depths allows to about 700 m.