Silly question about dry suit air usage

[boulderjohn]

The insulating qualities of argon compared to air has been challenged in some studies, but many divers swear by it. It is definitely better than helium, though.

 

[paddler3d]

I thought argon was used for drysuit gas inflation since it was thought to have better insulative properties than regular air. AFAIK, this hasn't been proven by any scientific study, but anecdotal reports support the notion.

The helium gas present in trimix has higher thermal conductivity than either argon or regular air. For tech divers using helium, I think a stronger case can be made to have a dedicated drysuit inflation bottle.

But, then again, I'm not a tech diver using helium mix, I don't use argon, and I don't have a dedicated drysuit inflation bottle. What do I know?

Like I said, I could have been making it up. I swear I found something at some point in time that one of the gasses, O2 or N2, at higher partial pressures can create some sort of acid when it comes in contact with perspiration causing the diver to get a rash.

 

[Rainer]

Pretty conclusive scientific evidence in favor of argon over air can be found in this recent study sponsored by the Office of Naval Research:

Rubicon Research Repository: Item 123456789/7789

Do note that suits were flushed of air for the argon trials (whether achieving such noted benefits actually requires six full flushes as opposed to less is not detailed).

 

[rfins]

The insulating qualities of argon compared to air has been challenged in some studies, but many divers swear by it. It is definitely better than helium, though.

I used argon for a few years when divng in 34-38 degree water..I did notice a slight increased value of insulation compared to air. I just went back to air...it was more convienant, eaiser and not that great of differnce.

I don't dive helium either but I'm sure the difference would be greater.

As for increase air usage with a dry suit ....I only use my BC on the surface so the air to adjust bouyancy at depth going into the BC or dry suit is about equal.

 

[boulderjohn]

Like I said, I could have been making it up. I swear I found something at some point in time that one of the gasses, O2 or N2, at higher partial pressures can create some sort of acid when it comes in contact with perspiration causing the diver to get a rash.

CO2 will combine with perspiration to form an acid--perhaps that is what you are thinking of. Of course, what would CO2 be doing inside your dry suit?

That is what causes acid rain. It is also what makes running water acidic enough to dissolve limestone and form caves, stalactites, etc.

 

[Bubbletrubble]

Pretty conclusive scientific evidence in favor of argon over air can be found in this recent study sponsored by the Office of Naval Research:

Rubicon Research Repository: Item 123456789/7789

Do note that suits were flushed of air for the argon trials (whether achieving such noted benefits actually requires six full flushes as opposed to less is not detailed).

Is a "purge cycle" defined as filling the drysuit completely (Michelin man-style) and then exhausting the suit completely? If so, I wonder how much of the 16-20% of "total suit insulation value" while using argon would be lost if researchers did not do the 6 purge cycles. There must have been some reason that they did 6 cycles...and not 3...or 1.

Do argon inflation drysuit divers typically do purge cycles prior to water entry?
How much of the argon bottle is consumed doing the necessary purge cycles?
I think the study supports the theoretical benefit of argon drysuit inflation. That says very little about the actual benefit argon inflation drysuit divers might experience in the real world without numerous purge cycles.

The study was only published as a meeting abstract. Usually, this comes in the form of a poster. Poster content is not typically peer-reviewed. (Not saying that any of the content of the abstract is out-and-out wrong.)

Sorry for the thread hi-jack.

 

[Rainer]

I'm assuming they did six cycles because it pretty much guarantees that there is no remaining air in the suit. The study does not address what benefits are had with less purge cycles. Yup, the relevant question is what would you get benefit-wise from 1-3.

I know when my teammates use argon (we often use air, especially here in warmer SoCal), we *do* first purge a few times with argon (we have a separate bottle for this). This really is a must.

I fully assume the poster is turning into a paper (the usual path with such things in academia, at least in my field). I don't doubt the findings, though. In any case, few single studies are ever really "conclusive", but this is admittedly strong scientific evidence finding a difference between argon (not a weak argon+air mix you'd get without *some* purge cycles) and air.

Is a "purge cycle" defined as filling the drysuit completely (Michelin man-style) and then exhausting the suit completely? If so, I wonder how much of the 16-20% of "total suit insulation value" while using argon would be lost if researchers did not do the 6 purge cycles. There must have been some reason that they did 6 cycles...and not 3...or 1.

Do argon inflation drysuit divers typically do purge cycles prior to water entry?
How much of the argon bottle is consumed doing the necessary purge cycles?
I think the study supports the theoretical benefit of argon drysuit inflation. That says very little about the actual benefit argon inflation drysuit divers might experience in the real world without numerous purge cycles.

The study was only published as a meeting abstract. Usually, this comes in the form of a poster. Poster content is not typically peer-reviewed. (Not saying that any of the content of the abstract is out-and-out wrong.)

Sorry for the thread hi-jack.

 

[Teamcasa]

It's TOTALLY meaningless. Totally. I can get 3-4 looong recreational dives off my AL6 inflation bottle. That's <2cf for the dry suit per dive. MEANINGLESS from a gas management perspective.

Right. Unless you are really going crazy with inflation/dumping air, the amount you use on any one dive is negligible.

Argon? Just not worth the cost or effort IMO.

 

[Rainer]

Argon? Just not worth the cost or effort IMO.

Here in SoCal? I agree. In MoCal, or back in MA (35F in winter), that $6 argon fill could make the dive noticeably more enjoyable (not a huge difference mind you, but noticeable at least for me), especially for those who already tend to get cold.

If you're already dropping a few hundred dollars for a deep trimix dive (charter+gas+etc), argon cost is negligible. If the water is already warm enough, the dive is short enough, or you don't bother to purge the suit with argon a few times before the dive, you aren't going to notice a difference, in which case why bother.

 

[Mattleycrue76]

Oh yeah! It's very noticeable. That's a big part of the reason a lot of dry divers use a separate tank just for suit inflation.

I'm assuming you were being sarcastic. On the outside chance that you're serious this post demonstrates why one should be wary when seeking to learn diving on the internet