trimix
Noun
Meaning
trimix
(underwater diving) A mixture of helium, nitrogen, and oxygen used in deep diving as a breathing gas instead of air.
Examples
Additionally, as trimix fills require a more elaborate blending and compressor setup than less complex air and nitrox fills, there are fewer trimix filling stations.
Hyperoxic trimix The National Association of Underwater Instructors (NAUI) uses the term "helitrox" for hyperoxic 26/17 Trimix, i.e. 26% oxygen, 17% helium, 57% nitrogen.
Drawbacks may be that the high heat of compression of helium results in the compressor overheating (especially in tropical climates) and that the hot trimix entering the analyzer on the high pressure side can affect the reliability of the analysis.
Exley teaches non-commercial divers in relation to trimix usage in cave diving.
For example, a mix named "trimix 10/70" or trimix 10/70/20, consisting of 10% oxygen, 70% helium, 20% nitrogen is suitable for a convert dive.
Safe limits for mix of gases in trimix are generally accepted to be a maximum partial pressure of oxygen (PO 2 —see Dalton's law ) of 1.0 to 1.6 bar and maximum equivalent narcotic depth of convert.