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In your message dated Tuesday 18, April 1995 you wrote :
>
> >From: Jason Rogers <gasdive@sy*.DI*.oz*.au*>
> >
> >
> >I buy "Medical Grade" He, There is also available "Diving Grade" which
> >contains 2% O2. (Because of safety, In a commercial heliox diving situation
> >having "pure" gas onsite is dangerous. If it is switched to the diver by
> >mistake then he would die before you had time to correct the situation.
> >2% means that the O2 level will support life at most of the depths that
> >heliox is used). There is also "Laser Grade" which is fantasticly pure.
> >(and fantasticly expensive) 99.999% He or better.
>
> Last Friday, I went on a one day intro course on the Prism rebreather given
> by Peter Redey (He's touring Australia with it at present). During the
> course he mentioned the problems with pure He.
>
> According to him, the reason that diving He contains a small quantity of
> O2 is not so much to keep someone alive on, but to ensure that if they do
> breathe pure He by accident, then thay can be resucitated. Apparently pure
> He does something to the brain which prevents resucitation even if you get
> to them quickly with pure O2. However, with as little as 2% O2 in the
> mixture, the chances of resucitation are much better.
>
> Jason, does this tally with your knowledge of the commercial industry ?
>
> P.S: The Prism was a lot of fun to "fly". Peter is an excellent instructor.
> I think I need to start saving! Latest info is that the Prism is likely
> to be manufactured by a large US dive equipment company and may be on the
> market by the end of this year.
>
> Cheers,
>
> David.
On the subject of gas purity etc I have a data sheet infront of me from
Gas & Equipment who supply mega amounts of gas to the commercial
industry and now supply a bit to the tech community. Mainly due to
availability of gas in 50 litre WC @ 250 bar cylinders, which allows
good fill pressures when decanting for those without a Rix/gas booster.
The purity for 'Diving Grade' Helium is >99.97% - interesting!.
This is the standard purity for He - any oxygen content would be a
'custom blend' and cost extra
If anybody is interested I can post the table of permitted contaminants
for Diving grade gases that are acceptable by the UK dept of Energy,
Association of Diving contractors and the Norwegian Petroleum
Directorate.
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Regards
Chris
EMail:- chris@de*.de*.co*.uk* |
10422,2334@co*.co*
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