Argon... Worth the hoopla?

[Mo2vation]

OK - I'm divin' dry and lovin' life.

I've read all the threads, and all the scientific theories (*yawn*) on Argon and its supposed dramatic increases in thermal properties, due to its higher molecular weight, etc. Most of the articles say it ain't all that - well, unless you consider a 10% increase in warmth all that.

And I've read through UP's argon bottle schlep and purge method, as well as others.

So I'm asking myself - what up with Argon? I'm not cold. I don't think. I mean, I wasn't cold in my 7mm...until I took it off

But really - the drysuit is warmer on the deeper stuff and the colder stuff in So Cal (the 49's to 55's) this time of year. And I'm currently using Nitrox, Air and/or methane for fill gas. I suppose a 10% - 20% increase in warmth would be cool (no pun...) but I'm thinking I need a harness system, a reg, hose, bottle, I need to hunt down an Argon source on the westside, etc, etc.

As you know, I'm a recreational OW guy - some deeper stuff sometimes, but no tek, no deco.

Have any of you made the move and regretted it and hung the little bottle up? Did you make the move and its the best thing ever? Is it in my head, the warmth dividend, or is it legit?

Is Argon worth the hoopla for a diver like me?

Thanks -

K

 

[Bob3]

There are 2 ways argon can keep you warmer. One is if you're diving mix (any helium), and the other is placebo effect.
Never underestimate the power of the placebo, it won't REALLY keep you warmer, you'll just think it does, which is almost as good.

 

[runvus4]

Argon may keep you warmer than inflating your dyrsuit with regular air, but not incredibly much more so. It will keep you warmer than inflating with a gas mix that contains a notable amount of helium, but filling your drysuit inflation bottle with air will get you pretty much the same effect for much less money.

You should select your drysuit undergarment so that you are comfortable when filled with air/nitrox. Then you will never need Argon. If you use Argon a lot, then with some simple math, you would quickly realize that the money spent on Argon fills could have bought you a warmer undergarment after a dozen or so dives. My LDS charges $1.00 a CF of Argon, and $4.00 for any air fill 40cf or less. If I was on Trimix and used an inflation bottle with air, even supposing I only used 10cf of gas per dive, counting filling/purging twice at surface, I'd be saving $6.00 a dive. If I wasn't breathing trimix and was able to use backgas to inflate the drysuit, instead of blowing $4.00 to fill a 6cf inflation bottle, then I'd save possibly $9.00 to almost $10.00 per dive.

Argon may be useful on an occasional basis to extend the comfort range of your drysuit undergarment by a small amount, but it should only be occasional use, as needed, not standard (and expensive) procedure.

 

[Mo2vation]

Sure, diving TriMix, high HE content, etc, it makes sense to carry a denser gas, as if I'm breathing HE and using that as a fill gas its way light in the insulation department.

If I'm breathing EAN 36, Air, etc. - using that as a fill gas is probably fine for my in and out diving. You could probably debate EAN or Air v. Argon for fill gas for deco hangs of any significance, but that's not in my future.

Its getting clearer. I think for me, rolling with my breathing gas will be fine. I'd rather spend the money on a nice trip than on another bottle and the required robotics.

K

 

[WillAbbott]

Though I've never really used Argon, I have had my suit filled at the surface, and it felt a wee bit warmer (not much)

There is some actual science to Argon here, which I feel was overlooked.

The gas itself is not "warmer" (it's not a heated gas or anything)

But the actual science is this. It is denser than air. It's density is closer to water. What does this do? Well for starters that means it doesn't compress as easily, meaning 1cf of air in your suit at 0feet would still take up close to the same space at 5feet, 10feet, etc. (not knowing the actuall density this is just an estimate). Basically with depth changes it doesnt change in it's size as much as air. So you end up using less of it per dive, and end up using your suit valves less. The other item is because of it's density it weighs less in water. This means one of 2 things, one you can put more gas in your suit with the same amount of weight, or 2 you can lighten your weight load and use the same amount of gas.

Argon also transfers heat at a lower less efficient rate (this is where the "warmth" comes from) which means that your body heat is not transfered by the gas to the outside of your suit, and finaly to the water as quickly as air (which we already know air insulates decently).

So, it's not WARMER, however it does insulate better, weighs less, and is less compressable.

I know people who use Argon and love it, and people who have never used it who say it's Junk. The sad fact is there is some TRUE science behind it.

Did you know one of the gasses that can be used in a "gas filled" window is Argon? Theres a reason theese windows are popular and used in "Super Good Sense" housing. It is PROVEN to have a higher insulation value. We all know the more and better you can insulate yourself from the cold water the longer you can stay comfortable in the water.

That being said, yes better undergarments would help, but you still have the same insulation value of the air, your still using an easily compressable gas, and a buoyant gas. The people I know who use Argon say it lasts them, Many dives, typically close to a month or so, because of it's density characteristics, which means you use less (also leaving just a little more air in your tanks for breathing)



Heres a little scientific info for you brainy science bums on the board. Provided by:http://www.techdiver.ws/exotic_gases.shtml#3.3

Argon (Ar) fact sheet:
Density: 1.662 g/liter (alternate source: 1.784 kg/m3)
Thermal conductivity: 0.01772 Wm-1K-1

Oxygen
Thermal conductivity 0.02658

Nitrogen
Thermal conductivity: 0.02583

Air
Density: 1.225 g/liter (alternate source of information, using a calculator) (1.225 kg/m3)

Water:
Density: (Alternate source:997 kg/m3)

Sea Water:
Density (alternate source: 1024 kg/m3)

I couldn't find the density of oxygen or nitrogen, however thier atomic weight is less than 1/2 of that of Argon

In just every ounce of info I could find (some not so helpful) shows that Argon has a much lower heat exchange rate, more density, etc. than air. As a matter of fact Nitrogen (which we know is more than 70% of the breathing air) is roughly 2times more conductive according to one source, and 1/2 as conductive as Water (in ice form)

Anyway, enough scince mumbo jumbo, I'm no phsycist, only took a little amount of physics, but the info I find on the web backs up the science of the benifits of Argon. Xenon would of course be a better choice, but has yet to be extensively tested as a dry suit gas, and is by FAR way expensive.


I should add, that though I don't currently use Argon I will in the future, once all my other gear is purchased. Esspecially now that one of my closest shops is doing Argon fills.

Just my .02 cents

 

[Bob3]

I've got a copy of "Thermal insulation properties of argon used as a dry suit inflation gas" that was scanned into a PDF file, be happy to email it to anyone that wants to check out a scientific study comparing argon vs air.
The study was done using divers & drysuits, not windows.

It's over half a meg, the printing was tiny so it needed to be scanned in high resolution.

send a PM & i'll zip it off to ya.
due to the requests, I've made it available for download: http://www.angelfire.com/ca/divers3/links.htm

article reprinted by permission, UHMS/ by Reisberg & Hope.

 

[Mo2vation]

too much science for one saturday morning....

This is the article I originally read:

http://www.decompression.org/maiken/Why_Argon.htm

Sounds like its not for me right now. Appreciate the input. Some of the tweeks I dive with use it - more for the tweek factor than anything else, I'm sure.

K

 

[runvus4]

Since the conversational approach may have been mis-interpreted:

1) Argon is less thermally conductive than air, so should be "warmer" when used to inflate a drysuit.

2) Argon is much more expensive than Air/nitrox.

3) You can easily and economicaly chose your undegarment so that for the vast majority of dives you do in recreational or even "technical" drysuit dives, you simply don't need the beneficial thermal properties of Argon over Air.

4) If you use air/nitrox and don't "purge" your suit repeatedly as some people do for Argon, you can use much less gas, perhaps 3cf to 6cf of gas. If that amount of breathing gas is statisticaly significant to your dive planning, or even an emergency ascent, then you had no business of going on that dive anyway. You really should have had larger tanks or another stage bottle before going on that dive.

5) Argon gas has it's place as a drysuit fill gas, just due to the economics of the gas, it is financially unsound to buy a less insulating undergarment to dive with, or not to layer an additional undergarment upon need, and instead use Argon to make up the heat loss for the majority of your dives. If your dive requires has undergarment max bulk requirements, or flexibility requirements that limit your chose to less insulative undergarments than you are comfortable, then the extra insulation that Argon provides makes then Argon or other low E gas is an excellent choice of drysuit fill over air. If you have an undergarment that you own and use for the vast majority of your dives and want to make an occasional dive for which the undergarment is a little too "light" after a reasonable amount of layering and wish for some extra warmth that Argon gives, then it is again an excellent choice instead of the initial layout for heavier undergarments that you will rarely use.

Argon is a denser gas than air. This means that it is heavier than air, in water or out of it, but using your numbers, 0.5kg difference between Argon and Air for a cubic meter really isn't much of a difference. Certainly being slightly denser, Argon is slightly less bouyent than air, but again, usiing your numbers and figuring that you don't have nearly one cubic meter in your drysuit, perhaps one 30th or one 18th of that amount, or about .028kg or .017kg difference, or about as much extra weight as a small bag of potato chips, less than one of the excersise/energy bars that people consume on the boatride out to a dive site.

I don't know if Argon is significantly less compressable than air such that there is any other benefits for bouyency control while changing depths, but I have never heard that line of reasoning used before.

Argon isn't "junk", it's just too expensive for the benefits it gives compared to less expensive and equally effective alternates to use it regularly for most people. If you can easily afford the Argon costs and prefer to be more flexible/less bulked up by wearing ligher undergarments over heavier undergarments, then Argon gas drysuit fills are a reasonable option to consider.

Anyway Mo2vation, I'm glad that you were able to come to a conclusion as to what your immediate needs are, ahve fun with your diving.

 

[Bob3]

Had several requests for the file, so I've posted it for download. Here's a link to a page that has the study performed for the Norwegian Navy (scroll down to the bottom of the page):
http://www.angelfire.com/ca/divers3/links.htm

Bottom line: argon used as a drysuit gas had no benefit over air.

 

[runvus4]

I've read that study and I am afraid that I disagree with the findings. I also question the measurement meathodologies that they used to support the findings.

The human body is a very strange creature, especially when measuring heat loss. The human body is very adept at maintaining core temperature at the expense of the extremeties. Measuring "mean skin temperature" is just not an effective way to gauge heat loss of a human body due to the huge standard deviation from person to person. All recent hypothermia studies are measured by core body temperature loss, not mean skin temperature as core body temperature measurements have much much smalller standard deviation from person to person.

The rectal measurements that the study made is more reliable as it is a more accurate reflection of "core temperature" loss, as would have the urine temperature tests, had they done urine temperature tests upon surfacing. Indeed, the mean temperature loss for the rectal measurements reflect ~22.8% less core temperature loss for people using Argon vs the people using Air. This unfortunately is not any proof of Argon actually being more effective, as the measured standard deviation is more than enough to obscure any difinitive conclusions. The study notes this as well stating "Though the nominal reduction in recal temperature was greater during air compared to Argon dives (0.57deg vs 0.44deg C, Table 4, Fig. 2) this difference did not reach statistical significance."

If you note, the % deviation for the rectal temperature was by far smaller than the standard deviation of any other measurement they took. If the Standard Deviation of the rectal temperatures was enough to render a 22.8% difference statisticly insignificant, then that should be a sign that 6 divers was not a large enough study. To reach statistical significance, the measured heat loss difference would have had to have been greater than the theoretical difference of insulative properties between Air and Argon. As noted in the conclusion "The study design does not provide the required sensitivity to detect minor changes in heat loss between air and argon dives."

What is needed is more testing with a much larger number of subjects so as to be able to be able to generate a smaller % error rate such that any "nominal reduction" has a chance of being statisticly significant.

Anyway, I disagree with the assertion that Argon has no benefit over gas, and if you read the study, that just is not the conclusion of the study as they admit that they did not have the sensitivity to measure the possible difference. I do agree with the subjective part of their conclusion which states that the additional practical and operational consequences of adding argon gas, as well as the financial and logistical reasources did not merit the effort. Simply, the practical benefit is Argon is generally not nearly worth the long term financial costs for the vast majority of diving, as well as the operational headache of carrying the bottle around and getting it filled in addition to getting air filled.