Rec Trimix

[TheRedHead]

ok..
let me think here...........
dang this hurts...
if it ongases faster. .. and therefore offgases faster. than one COULD hold a arguement to shorter decompression... NO? mabye your both on the same page just not the same paragraph?

That's not even the argument we're having. We arguing the rate of ongassing of He which that paper proports to be about the same as the ongassing of Nitrogen. This goes against the conventional wisdom of what is being taught elsewhere.

 

[Diesel298]

That's not even the argument we're having. We arguing the rate of ongassing of He which that paper purports to be about the same as the ongassing of Nitrogen. This goes against the conventional wisdom of what is being taught elsewhere.

yeah i picked up on that in your last post......
if its the same as or close to nitrogen then how does that warrant any substantal difference in decompression time. hes saying it would be shorter times with He.
and like you said.. He. being absorbed at twice the rate as nitrogen is the standard consencus (sp)
and beig a lighter gass tends to make a decent conclusion...
one study is no where near enough to change the past 20 years or practical time tested tables.
and im not fimilat with GUE but there teaching that its simmilar to nitrogen?

 

[TheRedHead]

From what I gather diesel, there was an internet post that referernced a paper that may have suggested that He ongasses about the same as nitrogen. That would be a biggie if true. I'm not that familiar with GUE teachings either, but I'm sure Floater won't give up and may try to make things clearer.

 

[Diesel298]

ok yeah im looking at some of the previous posts and filling in on a few holes i missed while arguing the needlessnedss of a 35 fsw END.
but anyway,
as fun as this has been i need to work tomorow.
as alway im intrested in and real info that proves or disproves a theory...
so ill revisit this tomorow.....

but to all
good night.
dive safe

Ray

 

[TheRedHead]

Kiss Gidds for us, Ray. :laughing:

I'll check in tomorrow too...

 

[Rick Inman]

From what I gather diesel, there was an internet post that referernced a paper that may have suggested that He ongasses about the same as nitrogen. That would be a biggie if true. I'm not that familiar with GUE teachings eith er, but I'm sure Floater won't give up and may try to make things clearer.

HERE'S some more interesting data on this subject - because the answer is all about the different compartments, for example, this sentance from the text:

"In lipid tissue, the outward flux of nitrogen from bubbles exceeds the inward flux of helium, whether the exchange of gases in the tissue is limited by perfusion or diffusion."

 

[*Floater*]

if its the same as or close to nitrogen then how does that warrant any substantal difference in decompression time. hes saying it would be shorter times with He.p

The post I linked to was a summary of a presentation at a GUE conference by David Doolette who had talked about his study for the Navy at Duke University, though the name of Doolette's paper was not mentioned and perhaps has not been published yet (the post was in Nov 2005).

Anyway, the post related two claims (though this is second hand info): 1) He and N2 uptake rates are about the same, and 2) He washes out faster than O2.

So therefore He mixes would require shorter deco than equivalent N2 mixes which George Irvine has been saying all along based on his experiences.

and im not fimilat with GUE but there teaching that its simmilar to nitrogen?

I don't know what type deco GUE classes recommend; I've only taken DIRF from GUE. I just know what GI3 recommends in this regard and that I've posted already.

 

[dherbman]

Kiss Gidds for us, Ray. :laughing:

I'll check in tomorrow too...

Red Heads are trouble.

 

[Kevrumbo]

Trump Card here people; "CO2 Retention, the Dark Narc and the use of Helium":
http://www.scubaboard.com/showpost.php?p=1629303&postcount=21

 

[TSandM]

I just got done having a very interesting and productive discussion by PM with another SBer on another subject. My point there was that, to develop a really valid algorithm for dealing with a given situation, you need DATA -- you really need to know what the most likely failures would be in order to know where to start diagnosing and treating them. The data aren't there.

And that's true for so much of this. The data just aren't there. Too much of what we discuss is purely anecdotal.

I had a bad narcosis experience at 100 feet in poor viz and low light. It has left me reluctant to return to those depths under those conditions. But are the conditions really relevant? Or is it simply that those conditions create the challenges that make the narcosis-related reduced function more obvious, sooner? I heard a story from my GUE instructor about a narcosis event at 100 feet (on air) where he was completely unaware of the fact that his inability to complete a task was related to narcosis, until he ascended and was then able to complete the task. This was a diver with many, many times my experience and training, and narcosis got to him.

The diver who says you can learn to deal with it makes me suspicious. I deal with a lot of people in the ER who think they can drive when they're intoxicated, until some combination of events proves that they can't, either.

If a rec triox class properly trains people in the buoyancy, team skills, problem solving AND gas management skills to dive the 80 to 130 range using helium, is there anything wrong with it? Before I make routine trips to those depths in our waters, I would want something to breathe that didn't have the effects I experienced before. If I can't afford the gas, I won't do the dives . . . I'll just stay shallower, where I can think. Other people may make different decisions, and it's up to them. I personally think GUE has a good point, but again that's based on anecdotal experience.