Why is Argon not used?

[Kendall Raine]

Jim Bowden used 80/20 Argox during the Zacaton project reasoning that Argon's lower diffusivity (Graham's Law) made it preferrable to 80/20 Nitrox for long deco's. What he didn't recognise, amongst many things, was the solubility differential worked against him. He bent the snot out of himself on several occasions. I don't know whether he ever figured it out.

You can still see the same type of mindlessness (fear of diffusion rates rather than lipid solubility) in the deep air instructional programs (e.g. PADI/DSAT).

 

[BRW]

Well said, Kendall,

With mixed gases, it's ALWAYS solubility
times diffusivity for staging. That's been
a chronic problem, sadly, for a century back
to Haldane dissolved gas only protocols.

Right behind argon is deep air, something
slightly less problematic than argon.:boom:

So also with deep switches to nitrox.:boom:

Believe we (Tim O'Leary and myself) convinced
Jim of same, and devised some helium schedules
for his next assault at Zacaton with RGBM.
That was a few years back too.

Serious business here (800+ fsw), no matter
how you cut it. Just like the RGBM schedules
Ellyat dived up in the North Sea on the Baden
at 540+ fsw, and with deeper plans to 1000 fsw.

Very serious, and much more so than the
expedition we are planning to Nepal for high
altitude dive and high altitude deco dive record
near the 19,000 ft level. Risks always
track with absolute pressure, and ambient
pressure in Nepal will be below 16 fsw (though
depth will double effectively for deco staging
compared to sea level),

Jim hasn't gone back to Zacaton from our
most recent communications to date.

Regards to all,

Bruce Wienke
Program Manager Computational Physics
C & C Dive Team Ldr

 

[Kendall Raine]

Thanks, Bruce.

I don't know whether Karl Shreeves doesn't know what mass transport is or whether the PADI helium boogey man is a marketing cloak for getting people into "tech diving" on the cheap (deep air). Doesn't really matter, I suppose. In fairness, I probably shouldn't single Karl out, either. He's not the only one.

Have a lovely time in Nepal and don't forget to off gas at the Yak and Yeti.

 

[BRW]

Kendall,

There are plenty of misconceptions about
mixed gas diving out there -- fervent religion
to naked misfact to pure nonsense.

Some recent articles in Traning Agency pubs
do underscore such. I mentioned the recent
PADI article about bubble models (RGBM
for focus)in an earlier post. Way off the
track. And I am not slamming PADI nor the
individuals who wrote it. PADI is a fine
recreational Training Agency.

Also maybe check IANTD, TDI, and others
about tec "deep air" courses too. Ouch!!

BTW, GUE and NAUI are the first on the block
with modern approaches to diver staging. And
info does flow between all Training Agencies

So times are changing for all of us. That's
a good thing.

Cheers to all,

Bruce Wienke
Program Manager Computational Physics
C & C Dive Team Ldr

 

[Goeduck]

Dr Deco once bubbled...
Dear SCUBA SOURCE Readers:

Argon

Argon is a good rat poison.

Dr Deco :doctor:

Hmmmmm, I wonder if it would get rid of the mole metropolis in my back yard.