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> > ---------------------------------------------------------------------- > > Sheck used a 20% safety factor unless diving deeper than 300 feet he > used o% on thise dives and if the dive was longer than 40 minutes he > used 0%. > ---------------------------------------------------------------------- > > I use a 20% safety factor with Doctor X as I know I don't have a PFO. > ---------------------------------------------------------------------- > > I use DRX a couple of times a week on trimix dives and also on air and nitrox > dives. I am a woman and have a problem with skin bends so I do a lot of gas > changes and this minimizes the problem. I use the program with a 50% safety > factor. My husband uses it with a 15% safety factor. (he has a lot less fat > content to his body than I do!!) > ---------------------------------------------------------------------- > > In reply to your request i use about 20% safety factor for 'normal' use. I > think that Sheck may have been hedging his liability bets in the US because of > the risk of getting sued. > ---------------------------------------------------------------------- > > DRX is a piece of crap for trimix dives. > 100% safety gives 100 for helium but 0 for > nitrogen. > Sheck was clearly more concerned with the helium, > but helium is the diver freindly gas, not nitrogen. > Buy/use another program. > I know of one diver who used 130%, with air/02 > deco, and he was so long on the deep air stops > he got a nitrogen bend on a trimix dive. > And another who used 30% safety on a nitrox dive, > he did not realise 30% is a straight buhlmann > for a nitrox dive, and got bent too. > > ---------------------------------------------------------------------- > > We work on real time dive jobs using Dr. Ex. Our base of standard tables is the > work done for our group done in 1991 by Dr. > Bill Hamilton. Dr. Ex parallel's these tables with a 10% safety factor. > Interestingly enough, I had a conversation with Sheck before his accident and he > told me this is what he used. > > ---------------------------------------------------- The general practice seems to be to use between 10 and 30% "safety" when using DRX. I assume people realise that when used for air or nitrox dives, anything between 0 and 100% safety gives 0% safety, or a straight buhlmann. There is no safety for nitrogen until the safty factor is above 100% . Even if you use trimix, the nitrogen safety does not cut in until you exeed 100% . EG 130% safety, trimix: 30% nitrogen, 130% helium. 90% safety, trimix: 0% nitrogen, 90% helium. 90% safety, air: 0% safety. Rod.
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