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George
You define the oxygen window as being the difference between the partial =
pressure of an inert gas on the arterial and the venous side of the =
tissue.
If the partial pressure of one gas does not influence another gas,=20
then why is it not more efficient to decompress on nitrox than heliox =
from a heliox dive?
Although nitrogen is onloading during this deco, I would have expected =
the oxygen window to be wider on the helium.
One might even picture toggling between nitrogen- and helium-based =
deco-gasses.
Torbj=F8rn Hamran
----- Original Message -----=20
From: George Irvine=20
To: Richard Waring ; techdiver=20
Sent: Friday, October 25, 2002 10:55 PM
Subject: RE: Heliox
We ran concurrent experiments using different gasses. Bill Mee did =
heliox, JJ did trimix with all trimix deco gases, I did trimix with =
helium only in the deeper gasses. We were looking for advantages or =
disadvantages.=20
What we found is that Bill Mee got the fastest and cleanest deco. I =
had no issues with my gas. JJ got an improvement over using my gases.
We use as much helium as we can conveniently get in all gases. Our =
only rule is the minimum helium for gases used to dive ( as opposed to =
decompressing - 35 minimum vs 25 for the 120 deco gas ). We have minimum =
standard gasses as well as to helium, maximum an optimal PPO2s, and =
standard oxygen percentages for deco gases.
You are taking the term "air break" literally. The intent of the term =
is to get as close to a normoxic PPO2 as possible for breaks, which is =
generally going to be your deepest gas, which is by definition going to =
be helium based in the WKPP. We do not dive air for anything, we do not =
dive nitrox for anything ( but we do decompress on it).
Obviously, the guys with Haskel pumps can get to pure heliox or =
whatever they want. I generally keep mine a little on the high side for =
two reasons: one, it makes the stage bottles neutral, and two, it is a =
better gas. However, I have to drive 24 miles to pick up helium, so =
Haskel all the leftovers back on top of my doubles, and I eventually =
end up with heliox. I have a large compressor and a Haskel, so I don't =
have to deal with the usual nonsense.
Just a side note - the couterdiffusion thing is BS. It is like all the =
other deco bs - designed to explain why people who should not be diving =
get bent, or in the case of couterdiffusion, why pigs get skin bends, =
but then that is merely for people who have never seen bacon and don't =
know how ludicrous this really is.
-----Original Message-----
From: Richard Waring [mailto:newkitric.hellsbells@vi*.ne*]
Sent: Friday, October 25, 2002 3:32 AM
To: techdiver
Subject: Heliox
While the list is quiet I have a question aimed mainly at Trey, I =
know one of your team uses heliox and wonder why you don't. On the same =
subject if I have dived heliox back to 6 meters and switch to pure o2 am =
I better off braking on to air or going back to helix I know there is a =
problem with counter diffusion if I use air but don't understand the =
full implications. Ric Waring
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<DIV><FONT face=3DArial size=3D2>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial=20
size=3D2>George</FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002>You define t</SPAN><SPAN=20
class=3D653191721-25102002><FONT face=3DArial size=3D2><FONT =
face=3DArial size=3D2>he=20
oxygen window as being the difference between the partial pressure =
of<FONT=20
face=3DArial size=3D2> an inert gas on the arterial and the venous =
side of the=20
tissue.</FONT></FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial
size=3D2><FONT =
face=3DArial=20
size=3D2></FONT></FONT></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial
size=3D2><FONT =
face=3DArial=20
size=3D2>If the partial pressure of one gas does not influence another =
gas,=20
</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial
size=3D2><FONT =
face=3DArial=20
size=3D2>t</FONT></FONT></SPAN><SPAN class=3D653191721-25102002>hen
why =
is it not=20
more efficient to decompress on nitrox than heliox from a heliox=20
dive?</SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002></SPAN><SPAN=20
class=3D653191721-25102002></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002>
<DIV><SPAN class=3D653191721-25102002>Although nitrogen is onloading =
during this=20
deco, I would have expected the oxygen window to be wider on the=20
helium.</SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002>One might even picture toggling=20
between nitrogen- and helium-based deco-gasses.</SPAN></DIV>
<DIV><SPAN
class=3D653191721-25102002></SPAN> </DIV></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002></SPAN><SPAN=20
class=3D653191721-25102002></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002>Torbj=F8rn Hamran</SPAN></DIV>
<DIV><SPAN
class=3D653191721-25102002></SPAN> </DIV></FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3Dgirvine@be*.ne* =
href=3D"mailto:girvine@be*.ne*">George=20
Irvine</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
title=3Dnewkitric.hellsbells@vi*.ne*=20
href=3D"mailto:newkitric.hellsbells@vi*.ne*">Richard Waring</A> ; =
<A=20
title=3Dtechdiver@aquanaut.com=20
href=3D"mailto:techdiver@aquanaut.com">techdiver</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Friday, October 25,
2002 =
10:55=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> RE: Heliox</DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT><FONT face=3DArial
size=3D2></FONT><FONT =
face=3DArial=20
size=3D2></FONT><BR></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff size=3D2>We=20
ran concurrent experiments using different gasses. Bill Mee did =
heliox, JJ did=20
trimix with all trimix deco gases, I did trimix with helium only in =
the deeper=20
gasses. We were looking for advantages or disadvantages. =
</FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff size=3D2>What=20
we found is that Bill Mee got the fastest and cleanest deco. I had no =
issues=20
with my gas. JJ got an improvement over using my =
gases.</FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff size=3D2>We=20
use as much helium as we can conveniently get in all gases. Our only =
rule is=20
the minimum helium for gases used to dive ( as opposed to =
decompressing - 35=20
minimum vs 25 for the 120 deco gas ). We have minimum standard gasses =
as well=20
as to helium, maximum an optimal PPO2s, and standard oxygen =
percentages for=20
deco gases.</FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff size=3D2>You=20
are taking the term "air break" literally. The intent of the term is =
to get as=20
close to a normoxic PPO2 as possible for breaks, which is generally =
going to=20
be your deepest gas, which is by definition going to be helium based =
in the=20
WKPP. We do not dive air for anything, we do not dive nitrox for =
anything (=20
but we do decompress on it).</FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>Obviously, the guys with Haskel pumps can get to pure heliox =
or=20
whatever they want. I generally keep mine a little on the high side =
for two=20
reasons: one, it makes the stage bottles neutral, and two, it is a =
better gas.=20
However, I have to drive 24 miles to pick up helium, so Haskel all the =
leftovers back on top of my doubles, and I eventually end =
up with=20
heliox. I have a large compressor and a Haskel, so I don't have to =
deal with=20
the usual nonsense.</FONT></SPAN></DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D653191721-25102002><FONT face=3DArial =
color=3D#0000ff size=3D2>Just=20
a side note - the couterdiffusion thing is BS. It is like all the =
other deco=20
bs - designed to explain why people who should not be diving get bent, =
or in=20
the case of couterdiffusion, why pigs get skin bends, but then that is =
merely=20
for people who have never seen bacon and don't know how ludicrous this =
really=20
is.</FONT></SPAN></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> Richard
Waring=20
[mailto:newkitric.hellsbells@vi*.ne*]<BR><B>Sent:</B> Friday, =
October 25,=20
2002 3:32 AM<BR><B>To:</B> techdiver<BR><B>Subject:</B>=20
Heliox<BR><BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>While the list is quiet I have a =
question aimed=20
mainly at Trey, I know one of your team uses heliox and wonder why =
you=20
don't. On the same subject if I have dived heliox back to 6 meters =
and=20
switch to pure o2 am I better off braking on to air or going back to =
helix I=20
know there is a problem with counter diffusion if I use air but =
don't=20
understand the full implications. Ric=20
Waring</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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