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The window has nothing directly to do with the inert gas itself, and the
type of inert has nothing to do with the window - it is the sum of the inert
gases, so it makes no difference "window-wise" whether you use argon, neon ,
krypton, nitrogen, helium or all of them mixed together.

What does matter , but has nothing to do with the window, is that the
different gases have their own independent pros and cons. Helium is easiest
to breathe, has no bad effects, argon is narcotic, the rest are expensive,
nitrogen is nitrogen.

What we are doing in WKPP with "toggling" is toggling between high ppo2 and
low ppo2. Keep in mind that these days we don't really run massive open
circuit dives in deep water, so our helium use is not that expensive.
Running it through rebreathers is a huge savings. I can use the same deco
bottles for several dives, and in order to make them useful as open circuit
bailout, I merely Haskel some more of the same gas on top of them if they
end up below about 2500 psi.

The most expensive dives for me are in the 100 foot range, since I now just
don't bother doing them without helium - too much of a pussy, can't take the
damage or handle the goober brain that it gives you.

Next time any of you are diving at 100 feet, write a math problem in your
book before you go and don't think about it or try to solve it on the
surface. Try it at 100 feet on nitrox or air. Then try it on land afterwards
and call the helium distributor and get set up.

Here is a simple one. You are going to tile the floor of the dive shop you
got the air from. The store is 1700 square feet, the tiles come in 18"X18"
squares. How many tiles do you have to buy. Save that for your dive. You
will puke when you realize that you just lost about 40 IQ points.
  -----Original Message-----
  From: Torbj�rn Hamran [mailto:thamran@ne*.no*]
  Sent: Tuesday, October 29, 2002 7:00 PM
  To: techdiver
  Subject: Re: Heliox


  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,
  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�rn Hamran

    ----- Original Message -----
    From: George Irvine
    To: Richard Waring ; techdiver
    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.

    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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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 5.50.4728.2300" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =
size=3D2>The=20
window has nothing directly to do with the inert gas itself, and =
the type=20
of inert has nothing to do with the window - it is the sum of the =
inert=20
gases, so it makes no difference "window-wise" whether you use argon, =
neon ,=20
krypton, nitrogen, helium or all of them mixed =
together.</FONT></SPAN></DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =
size=3D2>What=20
does matter , but has nothing to do with the window, is that the =
different gases=20
have their own independent pros and cons. Helium is easiest to breathe, =
has no=20
bad effects, argon is narcotic, the rest are expensive, nitrogen is=20
nitrogen.</FONT></SPAN></DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =
size=3D2>What=20
we are doing in WKPP with "toggling" is toggling between high ppo2 and =
low ppo2.=20
Keep in mind that these days we don't really run massive open circuit =
dives in=20
deep water, so our helium use is not that expensive. Running it through=20
rebreathers is a huge savings. I can use the same deco bottles for =
several=20
dives, and in order to make them useful as open circuit bailout, I =
merely Haskel=20
some more of the same gas on top of them if they end up below about =
2500=20
psi.</FONT></SPAN></DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =
size=3D2>The=20
most expensive dives for me are in the 100 foot range, since I now just =
don't=20
bother doing them without helium - too much of a pussy, can't take the =
damage or=20
handle the goober brain that it gives you.</FONT></SPAN></DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =
size=3D2>Next=20
time any of you are diving at 100 feet, write a math problem in your =
book before=20
you go and don't think about it or try to solve it on the surface. Try =
it at 100=20
feet on nitrox or air. Then try it on land afterwards and call the =
helium=20
distributor and get set up.</FONT></SPAN></DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =

size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D823401711-30102002><FONT face=3DArial
color=3D#0000ff =
size=3D2>Here=20
is a simple one. You are going to tile the floor of the dive shop you =
got the=20
air from. The store is 1700 square feet, the tiles come in 18"X18" =
squares. How=20
many tiles do you have to buy. Save that for your dive. You will puke =
when you=20
realize that you just lost about 40 IQ points.</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> Torbj=F8rn
Hamran=20
  [mailto:thamran@ne*.no*]<BR><B>Sent:</B> Tuesday, October 29, 2002 =
7:00=20
  PM<BR><B>To:</B> techdiver<BR><B>Subject:</B> Re: =
Heliox<BR><BR></FONT></DIV>
  <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=20
  the 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=20
    did trimix with all trimix deco gases, I did trimix with helium only =
in the=20
    deeper gasses. We were looking for advantages or disadvantages.=20
    </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>What we found is that Bill Mee got the fastest and cleanest =
deco. I=20
    had no issues with my gas. JJ got an improvement over using my=20
    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=20
    well as to helium, maximum an optimal PPO2s, and standard oxygen =
percentages=20
    for 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=20
    size=3D2>You are taking the term "air break" literally. The intent =
of the term=20
    is to get as close to a normoxic PPO2 as possible for breaks, which =
is=20
    generally going to be your deepest gas, which is by definition going =
to be=20
    helium based in the WKPP. We do not dive air for anything, we do not =
dive=20
    nitrox for anything ( 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=20
    gas. However, I have to drive 24 miles to pick up helium, so Haskel =
all the=20
    leftovers  back on top of my doubles,  and I eventually =
end up=20
    with heliox. I have a large compressor and a Haskel, so I don't have =
to deal=20
    with 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=20
    size=3D2>Just a side note - the couterdiffusion thing is BS. It is =
like all=20
    the other deco bs - designed to explain why people who should not be =
diving=20
    get bent, or in the case of couterdiffusion, why pigs get skin =
bends, but=20
    then that is merely for people who have never seen bacon and don't =
know how=20
    ludicrous this really 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 =

      [mailto:newkitric.hellsbells@vi*.ne*]<BR><B>Sent:</B> Friday, =
October=20
      25, 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=20
      aimed mainly at Trey, I know one of your team uses heliox and =
wonder why=20
      you 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=20
      I 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></BLOCKQUOTE></BO
DY></HTML>

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