Helium Fraction and Standardized Gases

[boulderjohn]

Someone please help me to understand. I have to admit I stopped reading Kevin's posts a while back because they all seemed to ask the same question and make the same point over and over again. I think the point was answered over and over again. Someone please tell me where I am misunderstanding.

Kevin's point seems that there are better mixes that can be used for deco than the standard mixes used in DIR diving. That concept is frequently called "best mix" by other agencies.

In conceding that point, DIR says that those advantages may be real, but they are not as significant as some people seem think. This is indicated by the fact that a system for using standard gases during ascent has been worked out and it is working just fine.

There are advantages to using standard mixes apart from this issue.

In the DIR judgment, the advantages of using standard mixes outweigh the advantages of using a best mix philosophy.​

Please tell me where I am misunderstanding.

 

[PfcAJ]

I think you've pretty much got the gist of it, John.

 

[LiteHedded]

Kevin,

I'm afraid that you've just described yourself. You were given plenty opportunities to actually provide something of substance, rather than parroting an article that you once read.

This train wreck has run it's course. Can we close it now?

not until he wears out his ctrl, c and v keys

 

[lamont]

Kevin's point seems that there are better mixes that can be used for deco than the standard mixes used in DIR diving. That concept is frequently called "best mix" by other agencies.

I was always taught standardized gases were "minimum helium content" and that 21/45 or 21/55 could be still be considered a standardized mix.

Major point being that this differs from the 'best mix' practice of computing O2 content exactly based on some target max PPO2 and potentially having everyone showing up with different "best mixes" for the same dive (resulting in different decompression strategies, team separation on deco, etc).

Kevin uses 'best mix' in a really nonsensical way where the WKPP using 21/45 or higher helium mix would be considered "best mix" and a nonstandard gas, and that leads to a contradiction with JJ running a training agency promoting standardized gases based on the experience in the WKPP while simultaneously diving "best mix" blends in the WKPP. Pretty sure that if kevin tried to go over to the GUE forums and claim that in the grenade-hurling way that he has here that he'd get corrected as to what those terms mean and how they're used...

 

[Crush]

I was always taught standardized gases were "minimum helium content" and that 21/45 or Pretty sure that if kevin tried to go over to the GUE forums and claim that in the grenade-hurling way that he has here that he'd get corrected as to what those terms mean and how they're used...

REALLY not trying to be a PITA, but then why does the DIR forum exist on SB?

 

[Bombay High]

Someone please help me to understand. I have to admit I stopped reading Kevin's posts a while back because they all seemed to ask the same question and make the same point over and over again. I think the point was answered over and over again. Someone please tell me where I am misunderstanding.

Kevin's point seems that there are better mixes that can be used for deco than the standard mixes used in DIR diving. That concept is frequently called "best mix" by other agencies.

In conceding that point, DIR says that those advantages may be real, but they are not as significant as some people seem think. This is indicated by the fact that a system for using standard gases during ascent has been worked out and it is working just fine.

There are advantages to using standard mixes apart from this issue.

In the DIR judgment, the advantages of using standard mixes outweigh the advantages of using a best mix philosophy.​

Please tell me where I am misunderstanding.

There is a very real advantage when team diving, to use standardised gasses. It eliminates all kinds of confusion, and when you have a standardised protocol, it makes emergency response very efficient and effective. This is my understanding as a layman.

Lamont, the philosophy of using just enough helium also makes sense to me from a counter diffusion point of view. Is this the philosophy that created the standardised gases GUE advocates ?

I also know that I sound like a stuck record, but is Heliox not advocated because of a cost factor ? or is there another reason ?

 

[lamont]

REALLY not trying to be a PITA, but then why does the DIR forum exist on SB?

Well, taking your question at face value....

It predates the GUE forums by about 8 years.

Also, it is occasionally useful to pick up newer rec divers that are curious and don't know where to go for more information.

But the number of actual instructors and WKPP members on here is pretty limited, and Todd Kincaid appears to be quietly reading this thread and munching on his popcorn.

The kinds of questions that Kev is asking are well outside of the scope of diving that most members of this forum are doing, and Kev refuses to listen to Nick and most everyone else has given up. So if Kev wants a better authority -- JJ and Casey are both on the GUE forums -- and would probably be happy to put that 1999 article into context, and to set the record straight on what "best mix" and "standardized gases" mean along with what WKPP uses for 21% deco gas and how long a dive needs to be to require upping the helium content. And they'll have actually been informed by first-hand discussions with a lot of the decompression researchers.

The fact that Kev sits in the DIR forum on SB and lobs cut+pasted grenades at people and is afraid of the actual GUE forums should tell you all you need to know about him, however...

 

[lamont]

There is a very real advantage when team diving, to use standardised gasses. It eliminates all kinds of confusion, and when you have a standardised protocol, it makes emergency response very efficient and effective. This is my understanding as a layman.

Lamont, the philosophy of using just enough helium also makes sense to me from a counter diffusion point of view. Is this the philosophy that created the standardised gases GUE advocates ?

I also know that I sound like a stuck record, but is Heliox not advocated because of a cost factor ? or is there another reason ?

I'm sure the cost-factor makes it prohibitive.

Because its prohibitively expensive, there's also just not as much of a track record.

Do you know anyone that uses 21/79 on a routine basis? Maybe some CCR divers with more money than sense...

And JJ has a very strong bias to not fix something that isn't broken...

You need to show actual problems on actual dives that it solves (not solving theoretical problems on dives on paper), which is a principle that underlies most GUE/WKPP procedures. If you look at George's old "what is a stroke?" rant there's a line there which addresses this: " If you see something that [...] is designed to accommodate some phobia while ignoring all else, you are dealing with a stroke." That's the problem with solving theoretical issues at the exclusion to all else which is that eventually you'll run across the law of unintended consequences and you'll start causing more problems than you solve.

A silly example would be a diver worried about a collapse who drags a ton of shovels with him who is found dead tied up in line around all that gear.

Being paranoid about IBCD to the point of only using helium might work out okay, or you might find out that while some helium is good that completely eliminating nitrogen becomes counter-productive in some way... To avoid solving only theoretical issues, though, and to avoid reconfiguring your breathing gas simply because you're phobic of IBCD, you need to actually have encountered issues or know of dives that have encountered issues with 21/35 or whatever...

 

[Sat Diver]

[..........)

 

[Bombay High]

I'm sure the cost-factor makes it prohibitive.

Because its prohibitively expensive, there's also just not as much of a track record.


Being paranoid about IBCD to the point of only using helium might work out okay, or you might find out that while some helium is good that completely eliminating nitrogen becomes counter-productive in some way... To avoid solving only theoretical issues, though, and to avoid reconfiguring your breathing gas simply because you're phobic of IBCD, you need to actually have encountered issues or know of dives that have encountered issues with 21/35 or whatever...

Honestly its got nothing to do with being paranoid about IBCD.
I understand the cost issues though.
None of this is theoretical in my head.
As a commercial diver ALL my deep diving has been with Heliox. NO nitrogen.

I was just curious about how GUE arrived at their gas mix philosophy.

I understand that if it is not broken, dont fix it. But how did these mixes become sacred to begin with ?

What was the basis for the decisions that these are the right mixes and not some other combination?

I know that for commercial diving, keeping it restricted to one inert gas has advantages, from a saturation tracking standpoint, the fact that vestibular DCS becomes a non issue is a bonus.

I was truly interested in understanding GUE's take on it.

I get a rough idea from your answer .... paranoia , more money than brains, etc.