Argon Is it a myth

[Doppler]

I think the study you are referring to was completed by the Norwegian Navy and is available on the http://www.uhms.org/ undersea hyperbaric medical society website... I think. (I have a pdf someplace.)

Anyway, the report was published a year or so ago. It showed data from several working dives in very cold sea water. Subjects were rigged with thermal probes in just about every place imaginable... yes, there too. The results seemed to indicate that argon had very little advantage in practice over air as a drysuit inflation gas (theory notwithstanding). The conclusion was that the Norwegian Navy has reviewed the advantages of using argon compared to the steps that must be taken to keep it out of breathing systems and decided to stop its use... the hassle just is not worth the result, basically.

One thing worth note though... the article I have stated too that if you think it works better, great, keep using it. My advice now is, use it if you've got it and if not, use air.

By the way, a couple of 'friends' once got hold of my argon bottle and filled it with helium just before a dive in the Eagles Nest, Florida... it was an interesting dive.

DD

 

[Uncle Pug]

DanL once bubbled...
Pug, you're probably warm on argon when you first fill cuz you lug that steel 70 argon bottle along. Whew, I'm hot thinkin about it!

I don't lug a steel 70 around.... my P/U does.

placebos rule!!!

 

[Dan Gibson]

All gases compress the same? I don't think that is correct. You are using ideal gas laws as opposed to real gas laws. Maybe someone with more knowledge than myself can explain this a little better, but I do know that is incorrect.

Here is a good link to get started on differing compressibility.

http://www.atomox.com/gas_graphs.html

DanL once bubbled...
For example, argon was said to be more dense and compress less. BS. All gas compresses according to PV=nRT. Gas, any and all gas, is 1/2 the volume at 33ft as at the surface. At least that's what physics and basic PADI Open Water training tell me.

 

[DanL]

Dan Gibson -
You're right. Nothing is ever ideal. But at the moderate pressure range from 1 atmoshere to, say, 5 atm (about 75psi), the z-factor isn't a big deal. So the compression of gas in a drysuit will be pretty closre to ideal gas behavior over the range of typical diving depth. If the pressure on the suit got near 1000psi or above, the non-ideal compressibility would start to be a factor. Wouldn't be much of a concern at that point...

 

[MechDiver]

DanL once bubbled...
It's a myth. All that BS about gas density, thermal conductivity etc is only marginally important or plain wrong. Almost every point purported to be scientific explanation of argon benefit was simplistic and far from complete in condsideration of key factors such as psychrometrics, physiology, heat transfer etc

And, all the propeller head math and stupid assumptions aside, argon works, and is not an option when diving He. Are you a CW diver BTW?

If you don't want to use it, just say "I don't want to use it". I would rather be spared all the highbrow crap that doesn't disprove a durn thing.

MD

 

[omar]

Misguided DanL spewed...

For example, argon was said to be more dense and compress less. BS. All gas compresses according to PV=nRT. Gas, any and all gas, is 1/2 the volume at 33ft as at the surface. At least that's what physics and basic PADI Open Water training tell me.

Lets look at what REAL physics demonstrates. All gases compress differently. The compressibility of each is described by Real Gas Equations of State (EOS). The simplistic Ideal gas equation that you refer to does not reflect actual (real) behavior of gases. The compressibility of gases must be considered when filling tanks. As for low pressure behavior the ideal gas equation will work reasonably well but by no means does it acurately describe the behavior of gases as you imply.

Next, The dominant factor in heat transfer, in order, will be the thermal conductivity of the suit material, the undergarment, than the gas. This heat transfer (First Law of Thermodynamics) is described by physics as CONDUCTION or the transfer of heat across a barrier such as a drysuit/undergarment!!! Typically when determining heat loss for a person conduction is determined and then minor adjustments are made to account for convection (e.g. the dominant process of the two is conduction). With all things being equal (suit, garment etc) other than the suit gas, argon has an advantage over air (less heat transfer), and a definite advantage over helium.

Psychrometrics is the measurement of the heat and water vapor properties of air or simply put humidity and evaporation. It is an important process for crops and vegetation studies but in this case is not applicable.

So basically you need to go back and take a refresher course in physics and thermodynamics.

omar

 

[tinman]

MechDiver once bubbled...
And, all the propeller head math and stupid assumptions aside, argon works, and is not an option when diving He. Are you a CW diver BTW?

If you don't want to use it, just say "I don't want to use it". I would rather be spared all the highbrow crap that doesn't disprove a durn thing.

MD

...I would suggest you read Dr. Sawatsky's article. I have had the pleasure of hearing him present a very cogent summary of the reasons for closed circuit diving fatalities (he gave out a few "Darwin" or "Natural Selection" awards as I recall). As a physician, CC diving instructor and accomplished caver, he would seem to have the credentials & a pretty big "propeller".

That said, if you see some benefit, why change. It just seems based on research to date that the benefit lies more in the realm of psychology than physiology and physics. ..

 

[MechDiver]

tinman once bubbled...


...I would suggest you read Dr. Sawatsky's article

I have, thank you. I have also hung an argon bottle off my bp and actually used it underwater. It does make a difference, as it does to the 5 others I dive with.

MD

 

[Northeastwrecks]

While I'm aware that certain studies claim that the difference between air and argon is negligible, I feel a difference, particularly when I pre-purge my suit. Clinical studies aside, I feel more comfortable and my use of argon is therefore justified.

 

[oxyhacker]

Maybe a little OT, but Sitech had a pump at BTS for evacuating the from your suit before you start putting in the argon.

Looked sort of like a cheap air mattress pump with all the valves reversed, forgot to ask what it cost.

Shouldn't be hard to homebuilt one, out of a airmattress inflator, dustbuster or 12v car vac. Might be an economical alternative to purging.

Not that Ar works anyhow ;-)