Argon gas... How?

[Rick Inman]

I have 2 dives on my new Argon pony, and I'm wondering a couple of things:

1) Why does Argon gas keep you warmer (how does it work)?

2) How, exactly, does it compare to air? In other words, are there numbers to explain body temp retention with argon vrs. air?

3) Do you believe there is also some plecebo effect?

Thanks!
Rick

 

[Don Burke]

Rick Inman once bubbled... I have 2 dives on my new Argon pony, and I'm wondering a couple of things:

1) Why does Argon gas keep you warmer (how does it work)?

It has a higher insulation value. Argon is often used inside double pane windows to give a little more performance.

Rick Inman once bubbled... 2) How, exactly, does it compare to air? In other words, are there numbers to explain body temp retention with argon vrs. air?

I've only seen one report on one study and it was inconclusive. I'd like to try a double blind study one day. My experience is that the effect is small and flushing the suit with argon before the dive and using air for makeup works pretty well.

Rick Inman once bubbled... 3) Do you believe there is also some plecebo effect?

I think so.

When I started flushing my suit with argon, I would keep more gas in the suit than normal after the second flush and get in the water with the drysuit exhaust valve cranked down. Once in the water, I would flatten the wing and let just enough gas out of the suit to descend. At about 15 feet, I'd open the suit exhaust valve all the way. I need a couple of short puffs in the suit to get to 15 feet. From then on, I would just use the suit inflator to keep the squeeze off. That way I trapped a bunch of warm argon in the suit from when I was on the surface.

I discovered later that making the initial descent on the the drysuit with just air in the suit worked nearly as well since the air is pretty warm too. My guess is that the humidity in the suit doesn't let the argon perform up to it's full potential.

I still use argon when it is very cold. Every little bit helps.

 

[DA Aquamaster]

Argon has half the specific heat capacity of Nitrogen and Oxygen:

Ar Specific Heat Capacity = .125
O Specific Heat Capacity = .218
N Specific Heat Capacity = .247

Argon also has 2/3rds the thermal conductivity of Nitrogen and Oxygen.

Ar= 0.02 J/m-sec-deg
N, O = 0.03 J/m-sec-deg

So it takes less of your body heat to warm Argon in your suit compared to air and it is a better insulator conducting a third less of your body heat to the outside of your suit and to the surrounding water.

Placebo effect? Maybe. Personally I think if you think are are going to be warmer you will probably feel warmer. It would be relatively easy to test this with an experiment.

You would need a double blind control group where neither the experimenter or the subjects know what's in the inflator bottle. You would also need experimental groups for both air and argon where the subjects are told they have either air or argon but where half the randomly sampled group in fact has the other gas.

You would then do a pre-dive survey of their expectations for staying warm during the dive based on what they are told about the benefits of argon and then do a post dive survey about how warm the divers felt they stayed during the dive.

If you get a high correlation of percieved warmth when the diver thought they were using argon when in fact they used air then you would have strong evidence for a placebo effect occurring.

 

[DA Aquamaster]

Don Burke once bubbled...
My guess is that the humidity in the suit doesn't let the argon perform up to it's full potential.I

Humidity in the suit would be a factor whether air or argon was used in the suit. Water, in liguid or vapor form, has a very high specific heat compared to air or argon (1.0) and is a very efficient condunctor of heat. Consequently it has an adverse affect on the insulation efficiency of either gas in the suit.

But the relative differences between using argon and air in the suit would still be the same with argon having a 1/3 rd efficiency advantage over air. But with either gas, it is clear that the effectiveness of the insulation can be drastically redcued with moisture in the suit. Consequently do not want to work up a sweat in your suit before or during the dive and you want to ensure the underwear is thoroughly dried between dives to maintain peak efficiency.

 

[Boogie711]

between air and argon is rather minimal. Enough so that I doubt the majority of divers would recognize it.

But the difference between HELIUM and Argon is substantial - so if you're diving a Helium mix, Argon is definitely a good idea. If you're just diving regular air or nitrox, save your money.

The Norwegian Navy did a double-blind study and even used rectal thermometres :wacko: to discover the Argon effect, when using air or nitrox as a breathing gas, is basically a placebo.

 

[salty]

Argon and air will "feel" the same when used as a suit inflation gas. Argon as compaired to air has been showen to provide no major benifits in a "DRY" drysuit. However.............

Argo begomes a truly usefull gas when used with Thinsulit-B. This is the material used by DUI for there high end drysuit undergarments. Thinsulit-b unlike most other thinsulat materials is desighned to work under pressure. I belive it was orignaly develouped to be used in boot liners where the weight of a person and the tight bindings of the boot would be acting on it.

US Navy testing revieled that thinsulat-b worked well with both air and argon but when thinsulat-b became wet the thinsulat-b because of its desighn would hold the argon better than air. The wet thinsulat-b with argon provides more insulation than any other combanation.

When used as a combanation of argon and thinsulat-b the drysuit under garments will provide simular thermal capabilitys as most other undergarments. BUT once the undergarments become wet by a failure or leak in the suit Thinsulat-b when used with argon were the only combanation that kept a high thermal insulating quality.

Sorry for all the spelling errors.

Ron

 

[100days-a-year]

Just from a physics standpoint here are some thoughts,
1.Conduction will move heat away from your body much faster than convection,this would seem to indicate there is little thermal advantage beteen gasses as you will still lose most heat thru areas where you are in contact with your suit or thru your head,hands and feet, even if dry as there is less airspace.Twice as efficient wouldn't mean much if the total energy saved was only a few calories of heat.
2.Dry drysuit inflation gases may increase evaporation of normal sweat until the gas reaches it's ability to absorb moisture.

 

[Bob3]

Here's a link to a 500KB PDF file of the only scientific study that I'm aware of comparing air vs argon as a suit gas, reprinted/posted with permission from the Undersea Hyperbaric Medical Society: http://www.angelfire.com/ca/divers3/Argon.pdf

My take on it is if you're diving air (not helium mixes) & want to stay warmer, invest in an extra set of polypro undies.
BUT... never underestimate the power of the placebo. If you've convinced yourself you'll feel warmer, you probably will, even if the thermal probes up the butt say differently.

 

[Mo2vation]

Bob3 once bubbled...
My take on it is if you're diving air (not helium mixes) & want to stay warmer, invest in an extra set of polypro undies.
BUT... never underestimate the power of the placebo. If you've convinced yourself you'll feel warmer, you probably will, even if the thermal probes up the butt say differently.

Too Funny. When I started diving dry a year ago, I went through this whole search for "truth" on this subject, posted a ton of stuff here, read the studies, etc.

Without ever diving it, I concluded from what I read and from what people told me, that Bob is right on. The placebo is strong, you can't underestimate the gaget value (the whole robodiver thing...) and if I'm diving Air or EAN, I'll add another layer.

For me in those early days, the attraction was Robodiver. I got over it, and just throw on a vest if I'm chilly.

K

 

[Rick Inman]

Bob3 once bubbled...
Here's a link to a 500KB PDF file of the only scientific study that I'm aware of comparing air vs argon as a suit gas, reprinted/posted with permission from the Undersea Hyperbaric Medical Society: http://www.angelfire.com/ca/divers3/Argon.pdf

My take on it is if you're diving air (not helium mixes) & want to stay warmer, invest in an extra set of polypro undies.
BUT... never underestimate the power of the placebo. If you've convinced yourself you'll feel warmer, you probably will, even if the thermal probes up the butt say differently.

Thanks a LOT, Bob! Now that I read the study you linked us to, I'm convinced that I WON'T be warmer, hence the placebo effect is rendered nill. I'll be cold because of you.
Please send me $167.26 plus $5.00 for the Argon sticker and we'll call it even.