Recreational Helium?

[texdiveguy]

I hope you can appreciate that I might respect your experience and value your opinion without seeking your approval.

Don't have to have mine or anyone elses approval....just trying to give direct and honest input....you were the one that broached the question/s.

 

[Tomeck]

Here's the results of Meyer-Overton study for reference.... they argued (in 1908, I think!) that the narcotic effect of a gas was proportional to the solubility of the gas. In these results, a higher number means more narcotic..

Gas Bunsen Solubility Coefficient in Olive Oil, 22Ž°C, ata-1

Helium 0.015
Hydrogen 0.042
Nitrogen 0.052
Oxygen 0.11
Argon 0.15
Krypton 0.44
Carbon Dioxide 1.34
Nitrous Oxide 1.56
Xenon 1.9

Hydrogen is as narcotic as nitrogen according to the solubility, but we use hydrogen for the very deep diving?

 

[Blackwood]

Hydrogen is as narcotic as nitrogen according to the solubility, but we use hydrogen for the very deep diving?

The Meyer-Overton study is nice, but it doesn't go far enough.

Solubility is only one part of the equation. It seems to me that the amount of a gas which gets absorbed into fat tissues is irrelevant from a narcotic standpoint if that gas doesn't do anything to contribute to the anesthetic effect.

I personally resisted the notion of narcotic Oxygen for quite a while because I didn't buy that its solubility mattered beans... until I was directed to this 1978 study: Roles of nitrogen, oxygen, and carbon dioxide in compressed-air narcosis

In it, subjects were chamber tested with a variety of gases under pressure. Turns out that Oxygen is observably narcotic in and of itself. If I didn't dive standardized gases, I'd include it in my END calcs.



They didn't address hydrogen, and I don't expect to ever see such a study.

 

[Rainer]

I'd agree with that. Until we get some decent nuclear fusion reactors (EFDA-JET, the world's largest nuclear fusion research experiment) up and running, there's a fixed amount of Helium in this world and every time it's breathed out, it's gone....

To think that recreational (including "technical") divers have any real impact on He reserves (and subsequent pricing) is laughable. Breathe away with impunity.

 

[ltw123]

I'm currently taking a rec helium class and my outlook on the gas has changed, but not how I thought it would.

I was looking for a gas to use where 32% leaves off, from 100 - 130'. Unfortunately, no stop times are so short with this gas in that range, that it's hard to justify the expense for such a short dive.

I can still see it being useful in the 80 - 110' range to take the edge off on hard working, high CO2 dives, but those are few and far between.

For that 100 - 130' range you really need to do some O2 deco to get a good amount of bottom time. I'd say to go ahead and take adv nitrox and deco classes too. Then you have the tools to do a nice dive at that range.

Or accept that you're not going to remember the dive well and do a short dive on nitrox.

my $.02

 

[Bismark]

If I didn't dive standardized gases, I'd include it in my END calcs.

I think you are allowing for this anyways if you are calculating END as = (1-Fraction HE)x ATA. For example, for 21/35 at 150 ft (5.5 ATA) is .65 x 5.5 ATA or 3.6 ATA or 86'. You are assuming in this calculation that the 02 and N2 are equally narcotic.

 

[Blackwood]

I think you are allowing for this anyways if you are calculating END as = (1-Fraction HE)x ATA. For example, for 21/35 at 150 ft (5.5 ATA) is .65 x 5.5 ATA or 3.6 ATA or 86'. You are assuming in this calculation that the 02 and N2 are equally narcotic.

Correct. If I didn't dive standard gases (thus making the calc irrelevant) and if I didn't believe O₂ to be narcotic, I wouldn't calculate it that way

I'd do FN₂ only, not FN₂+FO₂ (aka 1-FHe).

 

[Bismark]

Correct. If I didn't dive standard gases (thus making the calc irrelevant) and if I didn't believe O₂ to be narcotic, I wouldn't calculate it that way

I'd do FN₂ only, not FN₂+FO₂ (aka 1-FHe).

I don't think it makes a difference whether you are using standard gases or not. Just that you are assuming 02 and N2 are both equally narcotic. That same calc would work for a great mix of 24/32 or equally impressive 16/42...........Might be time to get a new analyzer......

 

[Rick Inman]

To think that recreational (including "technical") divers have any real impact on He reserves (and subsequent pricing) is laughable. Breathe away with impunity.

OK, if you say so!

I was thinking, if supplies are really getting so low, we must have a good portion of it in our garage!

 

[Blackwood]

I don't think it makes a difference whether you are using standard gases or not. Just that you are assuming 02 and N2 are both equally narcotic. That same calc would work for a great mix of 24/32 or equally impressive 16/42...........Might be time to get a new analyzer......

What I'm saying is that I never calculate it.