Posted by JR Gordon on October 09, 2000 at 19:14:34:
In Reply to: Re: Rec Trimix (Triox) posted by kelphead on October 09, 2000 at 17:17:01:
Hi Kelphead,
I don't have specific knowledge as to what depths Jim has been diving with Triox, but that's really not the point. The benefit of Triox(hyperoxic tri-mix)to recreational divers is in the reduction of Nitrogen in your breathing gas. The depth,within reason, is irrelevent. The whole point is to reduce the nitrogen content, thereby reducing the inheritant narcosis. Like diving Nitrox, the 02 percentage is the critical factor in determing maximum depth. You simply respect the MOD (maximum operating depth)of that 02 percentage. The amount of helium you add to the mix within 5-10% has little effect on your dive plan or your NDL's.
Up to 100 fsw, I dive 32% 02, and 30% helium mix called a 32/30 Triox mix. At 100 fsw my pp02 is 1.3. I've used this mix repeatedly on The Yukon. For dives in the 100-150 range, I dive a 25/35 Triox mix, yielding a pp02 of 1.4. The main point here is that in both mixes you're cutting the nitrogen content and it's insidious effects in half! That's the whole enchilada, pretty simple huh?
So Jim's experiment has him actually diving a safer gas mixture than air-not what I'd call a risk. Your reference to Ron Fuller's death is without merit and misleading. His death, as I understand it, was the result of mechanical failure or pilot error. Helium had absolutely nothing to do with his death and your reference is tanamount to "witch hunting". It is irrresponsible for you to warn others to the risks of something you apparently have only a peripheral understanding of. It is this type of scare tactics from a vocal yet uneducated source that hinders the education and advancement of knowledge. The dynamics of mixed gases are simple and easy to learn. The effects of Nitrogen while diving are dramatically underestimated as evidenced by the alarming number of scuba deaths we've seen this year. Please take the time to get educated and you will then better understand the simple dynamics of mixed gas diving. It is simply safer!
JRG