Argon gas... How?

[Bob3]

... I'll be cold because of you. ...

I used to get into trouble over the Easter Bunny thing too. :tease:

 

[pasley]

I recently read a study in one of the dive magazines(don’t recall which one but is was in the last 3 months) on air Vs Argon as an insulator in a drysuit. The study used several divers over several days, part diving with ARGON, and Part with air in a blind study. The numbered suit tanks were filled by a party who was not present at the dives to avoid any influence. Divers were given suit tanks filled with either air or ARGON, the true contents of which were unknown to the divers. Divers partially submerged and filled and emptied their suits 3 times to ensure they had gotten rid of as much ambient air as possible. All divers were equipped with skin temperature sensors.

In part of the test the divers were told they were diving with ARGON (but 1/2 of them really were diving air), divers reported feeling warmer with ARGON even those who really had air!
Bottom line, the skin temperature sensors reported no appreciable difference between air and ARGON.

 

[Rick Inman]

pasley once bubbled...
I recently read a study in one of the dive magazines(don’t recall which one but is was in the last 3 months) on air Vs Argon as an insulator in a drysuit. The study used several divers over several days, part diving with ARGON, and Part with air in a blind study. The numbered suit tanks were filled by a party who was not present at the dives to avoid any influence. Divers were given suit tanks filled with either air or ARGON, the true contents of which were unknown to the divers. Divers partially submerged and filled and emptied their suits 3 times to ensure they had gotten rid of as much ambient air as possible. All divers were equipped with skin temperature sensors.

In part of the test the divers were told they were diving with ARGON (but 1/2 of them really were diving air), divers reported feeling warmer with ARGON even those who really had air!
Bottom line, the skin temperature sensors reported no appreciable difference between air and ARGON.

NO!NO! Will someone PLEASE tell my this argon stuff works! Besides, to a non-diver, I look really cool with all this junk hangin' on my tank....

 

[Uncle Pug]

Argon works.

 

[The Iceni]

pasley once bubbled...
. . . Divers were given suit tanks filled with either air or ARGON, the true contents of which were unknown to the divers. Divers partially submerged and filled and emptied their suits 3 times to ensure they had gotten rid of as much ambient air as possible. All divers were equipped with skin temperature sensors.

Hi Pasley,

Listen to your Uncle pug!

Anything that reduces heat loss has to be considered essential when diving in cold water over extened periods of time, such as hanging on the shot offgassing for hours.

The body is extremely efficient at maintaining core and skin temperture under thermal stress but this requires the generation of energy (by reflex metabolism in the liver.) The diver can FEEL warm while these stores are used up (to warm the skin!) but why exhaust these energy stores when you can put on a decent coat?

If such heat loss continues for an extended period the body's energy stores and coping mechanisms suddenly become exhausted and you will develop hypothermia. (My regulator was working fine right up to the point when I ran out of air??)

A victim of hypothermia does not feel cold. BEWARE!

While I tend to agree that using the helium in Trimix to inflate a drysuit is a very bad idea (long deep dives) and more heat is lost by respiration, even longer (total) periods in relatively shallow water using Nitrox or air to inflate the suit will be just as bad.

Surely its horses for courses?

By the way, the only valid mechanism to test the objective effects of Argon would be to perform a case-controlled double blind trial of rebreather divers using Argon vs. Air vs. Trimix in their suits and to measure their metabolic rates for each from their oxygen consumption.

. . . but why repeat work was performed many years ago in the lab?.

 

[Doc Intrepid]

I've used both. Lots.

I feel warmer using argon during long dives in cold water.

I don't really care WHY I feel warmer..., its enough for me that I do, indeed, feel warmer.

(It doesn't perturb me that a rectal probe might indicate otherwise.)

Go for it.

Doc

 

[Don Burke]

DA Aquamaster once bubbled... 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.

I disagree with that analysis.

Water vapor will have it's own conduction value and when combined with a gas will affect the conduction of the mix far more with a relatively nonconductive gas than with a relatively conductive one.

If the effect were a percentage, you'd be right. The studies would also show much better performance with argon. It isn't and they don't.

With the way thermal conduction works, the conductivity of the combination would be the weighted average of the component conduction values. That means a highly conductive component makes a relatively nonconductive component inconsequential.

Again, it's just a theory, but the only one I can come up with that explains the discrepancy.

Have you seen another?

 

[Don Burke]

100days-a-year once bubbled... 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.

1. the job of your insulation is to keep you from being in direct contact with the drysuit. Inside the insulation is where the suit gas lies. I wear some pretty hefty gloves and sometimes preload them with warm water. The 7mm hood helps a bunch with loss from my scalp.

2. Perspiration should stay the same for a given temperature and hydration state. Evaporation of that perspiration may change in different gasses.

 

[scubasean]

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.

If argon doesn't give you any warmth benefit above air, then why not use air in your drysuit inflator bottle when you are breathing an He mix?

After all, air is much cheaper and easier to get, right?

 

[paulwlee]

scubasean once bubbled...


If argon doesn't give you any warmth benefit above air, then why not use air in your drysuit inflator bottle when you are breathing an He mix?

After all, air is much cheaper and easier to get, right?

I think some people just do that.
But, argon is pretty cheap (unlike He) and if you are already diving trimix, the argon cost will be a drop in the bucket. I think that's why most trimix divers use argon instead of air, even though the benefits of argon are still debated.
(I haven't tried argon, nor do I dive trimix yet. This is all based on observing other divers.)