Argon

[rjack321]

In a tech class of mine, on day 3 the instructor decided to "save us some money" and use air instead of argon in our suit bottles. He didn't tell anyone, since we were all getting dinner at the time.

Holy cow, day 4 was cold!

So we were all moaning about how much colder we were the next day and he fessed up to not bothering to bleed the mix panel and just putting air in there (ahem, laziness!)

The Norwegian Navy study is most questionable in my mind because they used neoprene suits and a "wolly bear" undergarments. Not really similar to my shell and thinsulate.

If you aren't getting cold with air/nitrox, you won't be warmer with argon. But I find it gives me about 20 mins of extra BT before I start to get cold. It does have roughly 30% less thermal conductivity.

 

[divemaster_jim]

Relative Atomic Mass of Argon (Ar) is 40.
Relative Molecular Mass of Oxygen (O2) is 32 and of nitrogen (N2) is 28.Call the average 30 (very roughly as ratio O2:N2 is 1:4)

The density of a gas is proportional to the mass of its atoms or molecules,so Ar is about 1 1/3 times as dense as air,not 5 times.

I goofed, I was thinking 5 times warmer ( I may even have that wrong) here is a chart showing the gas densities.:11doh:
http://www.constructionwork.com/resources_details_1471densities_of_gases.html

 

[IndyScott]

It never made a difference to me.
So I went back to using my back gas.
Scott

 

[Doc Intrepid]

It never made a difference to me.
So I went back to using my back gas.
Scott

Does your backgas typically have helium in it?

 

[ScubaRandy]

Due to it's nonreactive, heat isolating properties, Argon is an excellent choice for drysuit inflation.... or is it?

Skin can be frostbitten easily by exposure to cold Argon gas. . Funny, we are talking about using it when diving in a drysuit, and most people use a drysuit in... cold water. It is recommended that skin be protected from the Argon.

Also, be careful when working around Argon. Since it easily replaces oxygen when inhaled, you can suffocate. Welders working with Argon as a buffer gas when welding titanium have to use SCBA gear when the O2 level drops below 19.5%.... Argon is tasteless and odorless, so you can't tell except by certain symptons that you have been exposed to it.

Google "Argon Exposure".....

 

[albane]

good point Randy

It is recommended that skin be protected from the Argon.

Also, be careful when working around Argon. Since it easily replaces oxygen when inhaled, you can suffocate. Welders working with Argon as a buffer gas when welding titanium have to use SCBA gear when the O2 level drops below 19.5%.... Argon is tasteless and odorless, so you can't tell except by certain symptons that you have been exposed to it.

Google "Argon Exposure".....

my drysuit valve is on the shell. i'm separated from it by my undergarment. i don't think there is much risk of the expanding gas frostbiting my skin
good point none the less

 

[rjack321]

Air and nitrox can cause frostbite too, its called adiabatic cooling.
http://en.wikipedia.org/wiki/Adiabatic_process#Adiabatic_heating_and_cooling

Same principle as the "hot fill" issues.

Not really a relevant issue with drysuit inflation, regardless of gas.

Argon cylinders, typically 6 or 13cf sizes in the US, should be marked: "Argon, do not breathe" so that nobody thinks its a pony bottle.

 

[IndyScott]

Does your backgas typically have helium in it?

No just nitrox.

 

[Meng_Tze]

If you aren't getting cold with air/nitrox, you won't be warmer with argon.

I agree with this. Maybe I have yet to be in cold enough water to experience getting cold from my inflation gas.

 

[Rick Inman]

Multiple studies from private to US Navy show very little thermo value of argon when used in drysuits...

Why are people always trying to talk me into being cold?

Please don't confuse me with the facts. Besides, my LDS needs the money.