That is if you believe that in the first place - the nitrogen causes
damage that needs hyperbaric oxygen treatment.

Paltz, Art wrote:
> 
> I don't think it's that cut and dry.  I think it depends on the amount of
> nitrogen in the bottom mix.  According to Buhlman (since it was referenced),
> if you've got a lot of nitrogen in the bottom mix then the O2 is going to
> get your our faster (greater N2 difference in the bottom mix).  Less
> nitrogen in the bottom mix and the 50/50 is going to get you out faster (the
> He difference is 100% and it comes out faster then N2).  According to
> straight Buhlman (using Decom with N2/He M's set to 0%) I get the following.
> 
> Same simple dive 130 feet for 45 minutes.
> 
> Using air you'll get out of the water in the following times.
> Deep stops, O2 deco - 87 minutes
> Deep Stops, 50/50 deco - 90 minutes
> No deep stops, O2 deco - 85 minutes
> No deep stops, 50/50 deco - 89 minutes.
> 
> Using air O2 wins both times by 3-4 minutes.
> 
> Say you are using a helium rich mixture, say 50% He, 21% O2 (want to keep
> the O2 the same when comparing.  What you would be doing with this mix in
> your tanks I don't know.
> 
> 130 ft, 45 minutes, 50% He, 21% O2.
> Deep stops, O2 deco - 130 minutes
> Deep stops, 50/50 deco - 117 minutes
> No deep stops, O2 deco - 128 minutes
> No deep stops, 50/50 deco - 114 minutes
> 
> 50/50 wins both times by 13-14 minutes.
> 
> With a lower Nitrogen bottom mix you're better off with 50/50 then the O2.
> I think it naturally comes back to picking the right gases for the dive.
> Naturally this is Buhlman's interpretation.
> 
> Hope this helps,
> Art.
> 
>         -----Original Message-----
>         From:   Oystein Mehus [SMTP:oymehus@on*.no*]
>         Sent:   Wednesday, January 12, 2000 8:50 AM
>         To:     Manos Manoli
>         Cc:     Tech Diver
>         Subject:        Re: I think I don't understand
> 
>         Manos Manoli wrote:
>         >
>         > Jeff i made many many tests with diferent Ean mixtures belive me
>         > 100% oxygen on 6 meters does a hell of a lot diference than 50% on
> all stops.
>         >
> 
>         This subject interests me. Do you have any references to
>         why this might be so? And why does not deco-programs
>         reflect this knowledge? According to the algorithms (at
>         least Buhlman) you'll get out sooner if you use 50% from
>         21m than if you go straight to O2 on 6m.
> 
>         Oystein
>         --
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