Here is some discussion on using heavy inert gases to get out of the water quicker. The original question sets this up pretty well. The idea is to increase the gradient of your N2 offgassing by having a "slower" inert gas mixed with O2. Hence discussion about Argox, Neox, etc. . .
Date: Sat, 6 Sep 1997 01:10:39 -0700 (PDT)
From: Jeremy Downs <dcrco@jps.net>
Subject: Argox in deco
You guys have been talking about deco for awhile now & I assume you guys have this
stuff down. So here's my question.
What do you guys know about argox as a deco gas? Awhile back I remember a group in South
Africa was successfully using it to get off N2 deeper without O2 dangers in their initial
testing. I never found a followup report about it.
I know argon is highly narcotic at depth and somewhat more expensive than oxygen, but if
used in the shallower stop depths it would lower your oxygen exposure. In OC it would be
cost prohibitive but in SC or CC it would be affordable.
Does the additional enert gas cause any deco changes or would it have the same effect as
100% O2? Have any of you guys had any experience with this? What am I missing, why isn't
this used or is it the OC cost issue.
Date: Sat, 06 Sep 1997 08:40:49 -0400
From: "G. Irvine" <gmirvine@safari.net>
Subject: Re: Argox in deco
Jeremy - Navy stuies released at the 1996 UHMS conference in Palm Beach showed that the
determinent is the sum of the inerts, and the other problem is the size of the Argon
molecule - too big and once it gets in, it does not get out on the same shcedule as teh
other inerts - a problem it its own right.
Date: Mon, 8 Sep 1997 11:37:19 -1000 (HST)
From: Richard Pyle <deepreef@bishop.bishop.hawaii.org>
Subject: Re: Argox in deco
My perspective is that it is not worth the trouble. In other words, the theoretical
advantages do not outweigh the lack of practical (empirical) experience.
Aloha,
Rich
At this point, Tom Mount mistakenly thought the discussion was about using Argon in the drysuit, but the replies to this erroneous assumption brought out more facets of the issue.
Date: Mon, 08 Sep 1997 18:20:23 -0400
From: George Irvine <gmirvine@safari.net>
Subject: Re: Argox in deco
Tom Mount wrote:
>
> Richard
> I will disagee with you on this one. Argon makes a great difference especially on
long deco stops.
Tom, they are talking about breathing it, where it makes no difference to the speed of the deco, other than the problems caused by the introduction of the larger molecule on long exposures, which then increases the need for deco - see the Navy publicaiton onth this introduced at the UHMS Proceedings in Palm Beach , fall 1995, for the supporting data. Also, only a maschocist would want to go to a gas that dense during a long exposure and add to the work of breathing , which increases the c02 production which heightens the risk of tox, etc, etc, etc, etc. and on and on and on.
Date: Mon, 8 Sep 1997 15:18:31 -1000 (HST)
From: Richard Pyle <deepreef@bishop.bishop.hawaii.org>
Subject: Re: Argox in deco
Hi Tom,
Do you mean to breathe, or to put in a drysuit? If you mean to breathe, is the advantage
based on empirical, or theoretical grounds? I've seen the math for a variety of profiles,
and the savings don't seem all that great on deco time - even on theoretical grounds. It's
only good for the shallower intermediate stops. I've found that by using high helium
content in the bottom mix, then waiting until I get back to relatively shallow water (i.e.
~100 ft) to switch to N2, the deco is not all that different (especially with
constant-PO2).
Aloha,
Rich
From: Scott Leimroth <diver@chilli.net.au>
Date: Tue, 9 Sep 1997 18:47:40 +1000
Subject: Re: Argox in deco
I read about someone diving neox open circuit once but it is also very expensive too. Have
any of you guys dived or experimented with any other strange combinations, or are He, N2
and O2 the main gasses of choice? Surely gas factories such as electronic breathers are
made for diving with expensive exotic gasses.
Date: Tue, 9 Sep 1997 01:29:13 -1000 (HST)
From: Richard Pyle <deepreef@bishop.bishop.hawaii.org>
Subject: Re: Argox in deco
I've thought about looking into "raw neon", which I am told is about 25% helium,
75% neon, and a lot less expensive than pure neon. Right now, I'm comfortable sticking
with N2 and He.
Aloha,
Rich
Date: Tue, 09 Sep 1997 12:32:43 -0400
From: Tom Mount <TOM.MOUNT@worldnet.att.net>
Subject: Re: Argox in deco
Richard
Excuse me, I had just subscribed and thought you were referring to Argon in the dry suit.
We did print a paper in the IANTD journal about three years ago that suggesed that on one
series of experiments Argon and oxygen at 21% seemed to give significant decompression
advantages. If I can find the paper I will post in. Since that time I have not seem any
info that seemed to be conclusive.
Tom
Date: Tue, 14 Oct 1997 10:48:28 -1000 (HST)
From: Richard Pyle <deepreef@bishop.bishop.hawaii.org>
Subject: Re: open circuit deco or closed
> On ascent, I'll *probably* (Haven't decided for sure yet) switch
> to air dil on the bottom, and do a flush when I reach some point
> in the ascent (which I haven't yet settled on). Rodney's been
> having good sucess with using TMX all the way up, and George's
> arguments against Argox deco, should apply to NTX deco too, so
> I might not switch to N2 Dil at all. Certainly, if I'm going
> to do a repet dive, I won't use any N2 in the deco.
>
> Cheers Jason =:)
The only real argument I've heard against argon as a deco gas is the paucity of real-world
data. The same cannot really be said for N2, though.
Aloha,
Rich
This closed the discussion for a few months until the following:
Date: Sat, 17 Jan 1998 15:30:39 -0500 (EST)
From: "William M. Smithers" <will@tradeware.com>
Subject: Argox for safer deco?
This recent talk about o2 window, N2/He gradients, and the deco issues with 100% O2 got me
thinking about using Argox for the 20/10ft stops.
I've heard of Argox basically being used as an experimental deco gas, but not regularly or
seriously.
Anybody know why? In theory, Argox should give all the advantages of deco on 100% O2,
while totally eliminating O2 toxicity concerns.
And if you're a believer in bubble mechanics, it would allow you to pull even really long
decos at 20ft without raising your CNS clock much at all (vs. hitting 100% of your clock
after 45 mins on pure O2). An Argox 50 would give a PO2 of about .8 at 20ft.
[In classic Smithers form, he then posted immediately:]
Actually, I should have been more precise, Argox would give the same He/N2 off-gassing
gradient (window) as 100% O2, eliminate O2 tox concerns, and offer less vasoconstriction.
The only thing it wouldn't have going for it the slightly lessened ability to
directly oxygenate any tissues where bubble formation was causing unnoticed circulation
blockages (if this does in fact occur).
-Will
This brought out a really interesting post
From: dgpete@zim.com (Doug Peterson)
Subject: Re: Argox for safer deco?
Date: Sun, 18 Jan 1998 12:14:45 -0500
Will,
I am new to this list so I don't even know if it will get posted but I'll toss in my 2
cents worth anyway!<G> I just had too since I'd hate to see someone make a costly
mistake here..
I was involved in some mixed gas experimentation in the early 70s at Makai Range for the
UofH Marine Options Program in conjunction with the AEGIR project and, along with dives on
most gasses you can think of, we did a number of dry dives on Argon. Basically as a
narcosis reference... Depending on the mix we did dives to 1, 2, 3, 4 ,5 and 600 fsw.
It has been a long time so don't quote me on the mix but I believe it was a 50/50 or 60/40
Argon/Ox mix. and I am pretty sure Joe stopped the tests at 100fsw. anyway, he stopped the
test series far short of the original parameters.
It was HIGHLY narcotic to most of the divers in the program... Of course with any gas you
will find various reactions to the different diluents but this one is one to stay away
from.
We underwent various physiological tests on the dry dives in the chamber at Makai. We had
our brain waves being recorded as we took math tests, physical dexterity tests and visual
stimulus/brain response times and a lot of other stuff... more than I care to
remember<G>.
One of the funny and memorable things that the guy running this torture chamber on us
stated was that Argon looked to be useful as a substitute for Nitrous Oxide in the
Hyperbaric Medicine arena! NO way he'd have scheduled us to do a wet dive on this stuff.
I tend to resist narcosis well with Nitrogen as the diluent but the argon hit me hard at
p/ds of around 100fsw. My partner for this series was a long time diving buddy and was
effected less by the Argon than I but he got narced on air much faster then I under any
workload. After the Argon dive he told me that he couldn't understand why I was laughing
so much.... again this was well short of the scheduled end of this series.
Of course it WOULD keep you a LOT warmer on your deco stops than the heli-ox.. no more of
those chills but you might not enjoy it if you were busy trying to buddy breath your rig
with a fish!<G>
Anyway, just my personal experience but there is no way on this planet I'd use it as a
deco gas.
Doug Peterson
Subject: Re: Argox for safer deco?
Date: Sun, 18 Jan 98 13:55:09 -0500
From: M2 <m2aqua@worldnet.att.net>
Ken Clayton did some deep dives using neon and argon mixes as a decompression gas. it was
written up in aquaCORPS #9, WRECKERS, "Neox Lite." Dr. Bill Hamilton
(70521.1613@compuserve.com) cut his tables as has info on it.
M2
Date: Mon, 19 Jan 1998 06:29:19 +1100
From: Rodney Nairne < topgun@onthenet.com.au
>
Subject: Re: Argox for safer deco?
Will,
Whilst using argon for deco gives a theoretically fast off-gassing of the other inert
gases (He & N2) you need to consider the in-gassing of argon. Sure argon diffuses at a
slower rate than either He or N2, but have you thought about how hard it will be to treat
a bend when some of the bubbles make-up gas is argon, a dreadfully slow gas?
Also from memory, argon is quite soluble. If so, that's not a plus either.
Lastly if you are anticipating using a buhlmann algorithm with argon, how will you
determine the a & b values. a & b values are experimentally derived (ie bending
divers). I doubt Buhlmann would have been so stupid as to determine a&b values for
argon, in fact I think he dismissed it as ausefull deco gas in the early days. (pre-1970).
A better solution surely (**especially** with a constant PO2 CC deco) is to use a rich
trimix or heliox, and make the switch to nitrox deco later rather than earlier. Say keep
the deco EAD no greater than 30feet, the old Haldanian max no deco depth. In this way you
keep the N2 loading low, whilst still taking advantage of a huge helium gas gradient for
the majority of your deco (from 50feet and up).
RN
AARG http://www.chilli.net.au/~diver/index.htm
Date: Sun, 18 Jan 1998 17:59:53 -0500
From: Ripley Quinby III < rquinby@snet.net >
Subject: Re: Argox for safer deco?
Noble gases exhibit a narcotic effect in direct relation to their atomic weight. Why? No
one knows. Anyone out there want to consider Xenon? At least its so dense you can see it.
Maybe the only benefit.
Regards,
Rip
From: andrew < andrew@cet.co.jp >
Subject: RE: Argox for safer deco?
Date: Tue, 20 Jan 1998 01:02:40 -0000
Will,
Interesting idea. Why not push it to the extreme? We have already decided that doing the
3m stop at 6m was better. If diving Argox50, why not do the whole deco at 20m? (Or
at least something that is reasonably safe considering the ongassing of Argon at 20m.)
Andrew
Date: Mon, 19 Jan 1998 11:42:57 -0500 (EST)
From: "William M. Smithers" < will@tradeware.com
>
Subject: RE: Argox for safer deco?
Nobody knows much about the on/off-gassing rates for Argon, besides the theoretical
calculations, and as another poster mentioned, catching a bubble partially composed of
Argon would really complicate chamber/IWR treatment. So I would think it best to stay away
from situations that carry significant risk of Argon loading until more is known. The
shallower stops shouldn't cause much on-gassing.
-Will
Date: Thu, 22 Jan 1998 09:30:22 +1100
From: Rod and Suzie < topgun@onthenet.com.au
>
Subject: Re: Argox for safer deco?
This is what buhlmann had to say:
"... for the heavy very readily soluable argon, the least tolerance (ie overpressure
of gas cf He, N2, Ar). For the change of gas from helium to a more slowly diffusing gas,
neon is preferred to nitrogen, although gain in decompression time would be slight.
Theoretically, the use of other inert gases has no advantage in comparison with well
established use of helium and nitrogen. Our own experience concerns helium and nitrogen
and to a lesser extent argon."
Soluability Whole Blood
Olive oil
helium 8.7ml/liter
15.7
neon 9.2
19.6
Nitrogen 12.8
66.1
Argon 25.7
146.1
RN
Date: Wed, 21 Jan 1998 22:51:14 -0500 (EST)
From: "William M. Smithers" <will@tradeware.com>
Subject: Re: Argox for safer deco?
Yes, but I believe the passage you are reffering to is in regards to use of the heavier
alternate gas as a bottom gas, *not* as a decompression gas. Your translation is bad,
relying on an inconsistent verb interpretation to make your case.
By Buhlmann's own formulae (and math is universal), the critical element in offgassing
speeds is dissovled gradient of an on-gassed inert gas vs. inspired partial pressure of
the same inert gas.
Any way you slice it, the gradient is maximized by eliminating the inspired partial
pressure for a given inert gas.
Hence, inspired Argon is virtually transparent, from the on-gassing perspective, to
dissoved N2 or He. It's simple, basic gas laws, and nothing more.
-Will
From: diver@chilli.net.au
Date: Fri, 23 Jan 1998 01:03:44 +1100
Subject: Re: Argox for safer deco?
From Buhlmann also
"If the smallest possible quantity of inert gas is to be accepted by the tissues,
argo is unsuitable as a replacement for nitrogen because of its high solubility in aqueous
solutions and fat."
I think the high solubility of argon would outweigh the small benefit of using it as a gas
either on the bottom or on deco.
Scott
Date: Thu, 22 Jan 1998 21:09:53 -0500 (EST)
From: "William M. Smithers" < will@tradeware.com
>
Subject: Re: Argox for safer deco?
First, the big effect is narcosis, which is moderated at shallow depths with a rich O2
blend. I certainly won't argue about Argon's unsuitability as a bottom mix, but the
solubility issue is primarily related to narcosis, as I understand it.
-Will
Date: Thu, 22 Jan 1998 17:05:58 -1000 (HST)
From: Richard Pyle < deepreef@bishop.bishop.hawaii.org
>
Subject: Re: Argox for safer deco?
I haven't read the long list of responses to this yet, so I'll just provide a
comment here in front that may or may not have already been put forth on this
thread.
If you step back and look at the grand picture of decompression theory and practice, it
really all boils down to the three words used by Bill Hamilton: "What works,
works."
We know most about "what works" with nitrogen, somewhat less about "what
works" with helium in saturation situations, and considerably less about
"what works" with helium in sub-saturation situations. We know very
little about "what works" for decompression with other gases, such as
Argon and Neon.
A few courageous souls (I am not among them) have found enough faith in theoretical
explanations of deco to experiment with alternative breathing gases (such as Argon and
Neon). But so far, it seems, the empirical data obtained from such experiments have not
yet demonstrated enough of an advantage to encourage more individuals to perpetuate
additional experiments (i.e., most forlks, at this point, are "more comfortable
with the devil they know").
Hope that helps...
Aloha,
Rich
Final analysis? I'm open to a synopsis on this one.
This page last updated: January 23, 2002