44 replies to this topic

[drbill]

Nitrox is at an infinite premium for me. Air is free. I'm used to it, I dive it to 180-200 ft. Nitrox is at about the same rates as Jamie quoted. I can't dive it to the depths I dive air unless it is a mix less than 21%. I do 250-350 dives a year. Nitrox would require me to have a real job, air does not. Besides, I'm not even nitrox certified so I can't dive Nitrox anyway... but will get certified eventually and carry it as my emergency (but not regular) deco gas.

Edited by drbill, 18 August 2006 - 03:03 PM.

[gcbryan]

Nitrox is at an infinite premium for me. Air is free. I'm used to it, I dive it to 180-200 ft. Nitrox is at about the same rates as Jamie quoted. I can't dive it to the depths I dive air unless it is a mix less than 21%. I do 250-350 dives a year. Nitrox would require me to have a real job, air does not. Besides, I'm not even nitrox certified so I can't dive Nitrox anyway... but will get certified eventually and carry it as my emergency (but not regular) deco gas.

If it's less than 21% it's not Nitrox.

[BradfordNC]

whats wrong with air?

not sure about any of you, but i've been breathing it my whole life.
doing fairly well with it.

don't see the need in suddenly going against eons of evolution.

[jextract]

Not to mention the PITA factor. My nitrox tank is O2 clean, because the primary place I get it filled does partial pressure (SSA in Woodland Hills, the other PP-fill is Malibu Divers courtesy of our own Grant Graves). Other places that fill it are banked, like Hollywoodivers. Now if I take it out on a boat that has it banked, I'm screwed at my primary LDS. If it's easy and not that much of a premium and is appropriate for my diving, I'll do it; if it's a lot more or a PITA I won't.

[PerroneFord]

Not to mention the PITA factor. My nitrox tank is O2 clean, because the primary place I get it filled does partial pressure (SSA in Woodland Hills, the other PP-fill is Malibu Divers courtesy of our own Grant Graves). Other places that fill it are banked, like Hollywoodivers. Now if I take it out on a boat that has it banked, I'm screwed at my primary LDS. If it's easy and not that much of a premium and is appropriate for my diving, I'll do it; if it's a lot more or a PITA I won't.

What are you talking about? Why can't you put banked EAN in your tank and then take it back to your local shop? This makes no sense to me.

[drbill]

Nitrox is at an infinite premium for me. Air is free. I'm used to it, I dive it to 180-200 ft. Nitrox is at about the same rates as Jamie quoted. I can't dive it to the depths I dive air unless it is a mix less than 21%. I do 250-350 dives a year. Nitrox would require me to have a real job, air does not. Besides, I'm not even nitrox certified so I can't dive Nitrox anyway... but will get certified eventually and carry it as my emergency (but not regular) deco gas.

If it's less than 21% it's not Nitrox.

The AAUS defines Nitrox this way: Nitrox is defined for these guidelines as breathing mixtures composed predominately of nitrogen and oxygen, most commonly produced by the addition of oxygen or the removal of nitrogen from air.

RXScuba.com states: Looking at the above definitions we see that nitrox is a combination of Oxygen and Nitrogen -- to be specific, any combination of Oxygen and Nitrogen results in Nitrox.

Most definitions I've seen simply state Nitrox is a gas mixture predominantly composed of nitrogen and oxygen. Those definitions do not state the mix must be higher than 21% (air). Some of the professional divers here state they dive EAN21.


So these do not preclude Nitrox mixes being 21% or less. Your mileage may vary.

Edited by drbill, 18 August 2006 - 05:34 PM.

[gcbryan]

Nitrox is at an infinite premium for me. Air is free. I'm used to it, I dive it to 180-200 ft. Nitrox is at about the same rates as Jamie quoted. I can't dive it to the depths I dive air unless it is a mix less than 21%. I do 250-350 dives a year. Nitrox would require me to have a real job, air does not. Besides, I'm not even nitrox certified so I can't dive Nitrox anyway... but will get certified eventually and carry it as my emergency (but not regular) deco gas.

If it's less than 21% it's not Nitrox.

The AAUS defines Nitrox this way: Nitrox is defined for these guidelines as breathing mixtures composed predominately of nitrogen and oxygen, most commonly produced by the addition of oxygen or the removal of nitrogen from air.

RXScuba.com states: Looking at the above definitions we see that nitrox is a combination of Oxygen and Nitrogen -- to be specific, any combination of Oxygen and Nitrogen results in Nitrox.

Most definitions I've seen simply state Nitrox is a gas mixture predominantly composed of nitrogen and oxygen. Those definitions do not state the mix must be higher than 21% (air). Some of the professional divers here state they dive EAN21.


So these do not preclude Nitrox mixes being 21% or less. Your mileage may vary.

Well, if they say EAN21 then they are clearly wrong since EAN stands for Enriched Air Nitrox. It's not enriched if it's 21%. I suppose if you simply call it Nitrox as you did in your initial post you could be technically correct, certainly 21% is nitrox but it's certainly not enriched. Since you mentioned less than 21% that would involve removing oxygen from air and I don't know of anyone doing that. You would go to Heliox or Trimix before doing that I would think.

[drbill]

[Well, if they say EAN21 then they are clearly wrong since EAN stands for Enriched Air Nitrox. It's not enriched if it's 21%. I suppose if you simply call it Nitrox as you did in your initial post you could be technically correct, certainly 21% is nitrox but it's certainly not enriched. Since you mentioned less than 21% that would involve removing oxygen from air and I don't know of anyone doing that. You would go to Heliox or Trimix before doing that I would think.

They're joking about EAN21.

However, there are deep divers that dive mixes with O-2 < 21% to avoid oxygen toxicity at depth. Most do Trimix or Heliox as you suggest.

Edited by drbill, 18 August 2006 - 11:11 PM.

[Walter]

You're both right. Nitrox is any mixture of oxygen and nitrogen, although it is only EAN if the oxygen per centage is higher than 21. Typically when referring to nitrox, divers mean EAN.

[gcbryan]

You're both right. Nitrox is any mixture of oxygen and nitrogen, although it is only EAN if the oxygen per centage is higher than 21. Typically when referring to nitrox, divers mean EAN.

I know I'm right. My point was in referring to the statement of Dr.Bill:

"So these do not preclude Nitrox mixes being 21% or less. Your mileage may vary."

To my knowledge there are no Nitrox mixes less than 21% since that would require the removal of oxygen from air. At that point one would use Heliox or Trimix.

[6Gill]

Sorry about you diving air. But hey, if you like it...

Rumor has it that Walter has a tattoo that reads "Air...is just not for tires"

I use whatever efficiency on the dive calls for: air, EANx, Trimix and/or oxygen. (I might even start to use Heliox in my diluent tank for the CCR.) However, it has been only on an extremely rare occasion that I have used air in the last five years.

I'm in the same position as SDM but I understand earlier post about cost and hassel of diving something other than air(aka God's trox).We get our gases(O2 and helium) at rates better than the diveshops here plus don't have alot of the neccery overhead.We have access to multiple compressors and tanks(so if I mix up say a 18/45 but can't do the dive it no worries.If I need tanks for a 32% or 21/35 there is always a set around I can use.)So for me diving something other than air easy relitivly easy.The only time I'm diving below 30ft I'm doing deco(thus a gas other than air) or practicing skills(we just use left over gas from the dives 'cuse we would just be draining them anyhow)

You're both right. Nitrox is any mixture of oxygen and nitrogen, although it is only EAN if the oxygen per centage is higher than 21. Typically when referring to nitrox, divers mean EAN.

I know I'm right. My point was in referring to the statement of Dr.Bill:

"So these do not preclude Nitrox mixes being 21% or less. Your mileage may vary."

To my knowledge there are no Nitrox mixes less than 21% since that would require the removal of oxygen from air. At that point one would use Heliox or Trimix.

Neon is suppose to make a good inert gas to use.....

Edited by 6Gill, 18 August 2006 - 10:09 PM.

[PerroneFord]

Neon is suppose to make a good inert gas to use.....

Gives you that warm glow all over eh?


I'll take Hydrogen. But only when I'm chasin Sheck's records.

[6Gill]

Neon is suppose to make a good inert gas to use.....

Gives you that warm glow all over eh?


I'll take Hydrogen. But only when I'm chasin Sheck's records.

My understanding is that breathing quality neon is expensive(not much call for it).
If you choose to use hydrogen,being a non-smoker that's one less worry.COMEX(French commercial dive company has done lots of research in the use of hydrogen as an inert gas)

[drbill]

To my knowledge there are no Nitrox mixes less than 21% since that would require the removal of oxygen from air. At that point one would use Heliox or Trimix.

There are divers that do mixes < 21% for deep diving. Perhaps not commonly, but it is done by some.

[gcbryan]

To my knowledge there are no Nitrox mixes less than 21% since that would require the removal of oxygen from air. At that point one would use Heliox or Trimix.

There are divers that do mixes < 21% for deep diving. Perhaps not commonly, but it is done by some.

Sorry to be so argumentative Bill. There are many divers that do mixes with less than 21% oxygen. Trimix with less than 21% oxygen is referred to as a hypoxic mix. My point (which at this point doesn't matter) is that no one is using Nitrox with less than 21 %. At depth they are using less than 21% but no one is adding more nitrogen. They are either just using less than 21% oxygen with helium only (Heliox) or Trimix with less than 21 % oxygen and the rest being some helium and the rest nitrogen. It's just not Nitrox.