Drysuit gas

[vwdevotee]

I read the abstract for a journal article from the journal of undersea and hyeperbaric medicine, and it talked about the difference argon and air being negligible as far as actual diver heat loss is concerned. Can anyone who has dived both air and argon talk abou their experiences?


Here is the abstract.
Thermal insulation properties of argon used as a d...[Undersea Hyperb Med. 2001] - PubMed Result

 

[dave4868]

The abstract:

Thermal insulation properties of argon used as a dry suit inflation gas.
Risberg J, Hope A.
Norwegian Underwater Institute and Royal Norwegian Navy, Bergen.
Uncontrolled observations from the "technical" diving community claim superior thermal comfort when replacing air with argon as dry suit inflation gas during diving. The objective of the present experiment was to evaluate the effectiveness of argon compared to air during cold water diving. Body weight, urinary output, and rectal and skin temperatures were measured in six naval divers during two dives to approximately 10 m for 60 min. Level of thermal comfort was reported. Dry suit gas was either argon or air, divers and scientists were blinded for gas identity. Urinary output was approximately 200 ml less (P < 0.05) during the air than the argon dives. Rectal and all skin temperatures decreased significantly in both groups during the dive but no difference was measured between argon and air dives. Thermal comfort was not different between the groups. Replacing air with argon neither improves subjective impression of thermal comfort nor attenuates core or skin cooling during cold water diving to 10 meters of sea water for 60 min.
PMID: 12067149 [PubMed - indexed for MEDLINE]

Small sample.

I'd like to see the controls they used regarding position in the water, activity, diver hydration, diver size, etc.

Perhaps better would have been to have each individual diver have several dives with both gases under near identical conditions, then compare results for the individual.

Double blind, of course.

Dave C

 

[PanamaMike]

I read the abstract for a journal article from the journal of undersea and hyeperbaric medicine, and it talked about the difference argon and air being negligible as far as actual diver heat loss is concerned. Can anyone who has dived both air and argon talk abou their experiences?


Here is the abstract.
Thermal insulation properties of argon used as a d...[Undersea Hyperb Med. 2001] - PubMed Result

I think the big advantage isn't Argon vs Air
but Argon vs trimix.

--Mike

 

[TSandM]

It was a reasonable study, and bears out the mathematics of the difference in thermal conductivity between air and argon, which is not great.

My subjective experience is different. I did a non-blinded and not completely controlled trial of air versus argon for suit inflation last January. We did three days of diving in 43 degree water. The first day, I had argon. The second, I had "airgon" (argon bottle topped off with air). The third, I had air. Judging from my SAC rate, the dives were all similar in level of exertion, except the last one, which was a drift dive. My subjective experience was that I was more comfortable the first day than the second, and the third was the coldest. It was enough to motivate me to make the relatively small investment in an argon setup for myself.

 

[Gene_Hobbs]

Full paper is available here: Rubicon Research Repository: Item 123456789/2380

A nice discussion which includes comments fro Simon Mitchell can be found here.

 

[DA Aquamaster]

If you look at a periodic table and compare the the differences between argon and air (79% nitrogen and 21% Oxygen) the potential advantage of argon is fairly small with only a maximum reduction of about 30% -and that assumes the suit is perfectly purged of all air.

In practice it's very difficult to purge the air out of the undergarments and it will be far less than perfect even after being fully inflated and purged 2-3 times prior to or during the dive, but it gets better each time and/or the more argon is added. However, you still lose much of the potential advantage of argon as what is in the suit is to some degree "airgon".

Which is the primary argument for just using air in the first place. There is potentially some advantage to argon, especally if you inflate and purge the suit a few times before the dive and thenusea pee valve so you can leave the suit sealed and zipped all day. But the way it gets done in the real word, by most divers, the advantage is slight and with adequate undergarments it may not be worth the extra expense of argon when you can instead use air in the inflation system when diving trimix.

And that point needs to be made, if diving trimix in cold water, an inflation system is almost a must have item.

 

[vwdevotee]

Forgive my ignorance, I just got my openwater cert, but Trimix is mostly Helium, correct?

 

[Spragg01]

<snip>

"Body weight, urinary output, and rectal and skin temperatures were measured in six naval divers during two dives to approximately 10 m for 60 min."

I know it takes the conversation down several large notches, but it would take a bit of convincing for me to dive with a thermometer up my bum? Perhaps that's why they used Navy divers.

The most interesting thing about Argon use (to me anyway) is the psychological side as it relates to actual body condition. Physiological responses to stress (cold or otherwise) can be effected by psychological condition, and I think it's possible that the psychosomatic effect of thinking Argon insulates you better may actually keep you warmer, or at the very least, your body may not react as severely to how cold it actually is. That's just cool.

 

[Dirkadiver]

Forgive my ignorance, I just got my openwater cert, but Trimix is mostly Helium, correct?

It depends. To keep is simple, you can get different mixtures for trimix (different %'s of HE) just like you get different mixes of Nitrox (different %'s of O2). Depends on dive profile as to what mix you use.

 

[matt t.]

I always use a separate cylinder for suit gas. I have never noticed a difference between air and argon. I do however always use argon when diving helium just in case (isobaric counter diffusion). I try to minimize any possible trouble.