What advantages or dis-advantages does Heliox have vs. Trimix.? (the Cost differences aside)
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What advantages or dis-advantages does Heliox have vs. Trimix.? (the Cost differences aside)
Same thing different O2 percentages. Heliox normally has an elevated O2 percentage >21% as if it were a nitrox. Trimix is more generic and can have any O2 percentage including <21% or greater then 21%
This must be regional difference. I have never heard of a Heliox premix for diving at or above 21% O2 in the millions of cubic feet I have seen delivered for military and commercial diving operations. The vast majority was ~1-3%. The majority of tri-mix I have seen is around 17% O2 and below. I was taught that oxygen levels in Heliox, Nitrox, or Trimix were anything intentionally blended above 0% and below 100% O2. Enhanced Nitrox or EAN of course has oxygen levels above 21%.
Well I thought the US Navy considered heliox any mix of helium and O2 and the term is used that way in commercial diving. But recreationally NAUI and others here in the States consider heliox any trimix with >normoxic levels of O2. Things like 26/17, 25/25, and 30/30 are all considered "heliox" here (althought the term is not common).
Trimix being the more generic term for any combo of O2/He/N2