Heliox...

[PolsVoice]

I've heard that Heliox is sometimes used for really deep dives to decrease nitrogen consumption. Since there is no nitrogen in the mix (Heliox not Heli-air) does that completely eliminate the risk of getting bent? Or does helium pose a similar risk?

If it does eliminate the risk, why doesn't everyone dive Heliox instead of EANx? Is it a cost thing?

Just curious,

- PolsVoice.

 

[MikeFerrara]

Helium carries similar decompression concersns as nitrogen but it is much less narcotic.

One purpose for adding helium is to eliminate or reduce narcosis and the other is the ability to reduce the percentage of oxygen in the mix because oxygen at hight partial pressures is also toxic.

 

[PolsVoice]

Helium carries similar decompression concersns as nitrogen but it is much less narcotic.

One purpose for adding helium is to eliminate or reduce narcosis and the other is the ability to reduce the percentage of oxygen in the mix because oxygen at hight partial pressures is also toxic.

So Helium will boil in the blood also, where can I find tables for this to compare to EANx and Air? Are there any (obviously breathable) gasses that wouldn't bubble? or rather, any that wouldn't be absorbed into the blood at all by the lung tissue...

I'm thinking maybe some the heavier noble gasses might work since they are inert, but again, this is coming from a barcalounger chemist/biologist.

Thankyou, you are very informative,

- PolsVoice

 

[H2Andy]

I'm thinking maybe some the heavier noble gasses might work since they are inert, but again, this is coming from a barcalounger chemist/biologist.

yes, but they have their draw backs. for example, argon might be a good
candidate except it conducts heat like a mother**** so it leaves you cold
and shivering. however, it comes in handy as a drysuit gas for the same
reason.

 

[sheck33]

So Helium will boil in the blood also, where can I find tables for this to compare to EANx and Air? Are there any (obviously breathable) gasses that wouldn't bubble? or rather, any that wouldn't be absorbed into the blood at all by the lung tissue...

I'm thinking maybe some the heavier noble gasses might work since they are inert, but again, this is coming from a barcalounger chemist/biologist.

Thankyou, you are very informative,

- PolsVoice

Any gas will be absorbed to some extent and will bubble. As far as the body is concerned pretty much any gas is inert with regards to metabolism since only oxygen is metabolized. Noble gasses will bubble as does Helium, it really has nothing to do with them being inert.

 

[jonnythan]

yes, but they have their draw backs. for example, argon might be a good
candidate except it conducts heat like a mother**** so it leaves you cold
and shivering. however, it comes in handy as a drysuit gas for the same
reason.

I thought Argon was used as a drysuit gas because it doesn't conduct heat well.

I also thought Argon was significantly more narcotic than Nitrogen.

 

[H2Andy]

yes you are correct.

from NOAA's manual: Argon has narcotic properties and a density that makes it inappropriate for use as a breathing gas. However, it is frequently used for inflation of variable-volume dry suits for warmth, because its higher density reduces the conduction of heat.

i must be misremembering something. i seem to recall reading somewhere that
breathing argon made divers very very cold.

 

[ScubaK-Dawg]

yes, but they have their draw backs. for example, argon might be a good
candidate except it conducts heat like a mother**** so it leaves you cold
and shivering. however, it comes in handy as a drysuit gas for the same
reason.

Argon is also more Narcotic than Nitrogen, from what I hear.

 

[PolsVoice]

does the weight of the gas affect how bubbly (for lack of a better term) it is in your system?

i.e. would Kr36 have a higher/lower rate than He2 or N7?

does an elements boil/freeze point and how it changes under pressure (i.e. water boiling at lower temps at higher altitudes) have anything to do with this? and if you'll permit me to sound like I'm twelve years old... This is so cool!

- PV

 

[Dr Deco]

Hello PolsVoice:

Atomic Weight

Generally, the greater the atomic (or molecular weight in the case of nitrogen), the lower the boiling point of the liquefied gas and the more soluble it will be in water. The least soluble is helium but it diffuses very fast and can find its way into bubbles. The best gas, in the limit, would have a zero solubility. Such does not exist.

Argon

Argon is not a good gas for diving because it is very soluble and produces a great deal of decompression gas bubbles, especially in adipose (= fat) tissue. These are dumped into the venous system and can result in neurological DCS in some cases.

Argon is also quite narcotic.

Dr Deco :doctor: