EANx Gas

[CD_in_Chitown]

EANx32 would be 32% oxygen, etc.

Actually EAN32 would be 32% oxygen. When it's presented as EANx the oxygen is variable or unknown. Therefore it's technically improper to use x and a number, it's either/or.

FYI........

 

[VTernovski]

Learn to dive on air first then "worry" about other gases.

I am sorry, but I am going to haVe to call a BS on this statement. There is nothing wrong with using Nitrox right away.

 

[Green_Manelishi]

I am sorry, but I am going to haVe to call a BS on this statement. There is nothing wrong with using Nitrox right away.

BS? Hardly.

 

[Firediver]

Okok,.. I didn't come for critism about being abeginner diver or and Advanced.. I have only heard of Diving nitrox.. and no matter what level of diver you are.. your always learning.. I never learned about nitrox, so that is why I came here. I guess I will keep my mouth shut when comes to dives.. and certs..

 

[randyjoy]

Actually EAN32 would be 32% oxygen. When it's presented as EANx the oxygen is variable or unknown. Therefore it's technically improper to use x and a number, it's either/or.

FYI........

The EANx means Enriched Air NitroX - the x comes from Nitrox. You MAY drop the "x" label and refer to EAN32, but they are interchangeable. Check BSAC, NOAA, PADI, NAUI, etc. - most do not drop the "x".

 

[Firediver]

Thanks. I appreciate all the help.

 

[Drew Sailbum]

A few terms get tossed around and they do have slightly different meanings.

Nitrox = A gas mixture of Nitrogen and Oxygen, regardless of percentage of either. Plain old air is "nitrox". We tend to disregard the small percentage of other gas (Carbon Dioxide, Argon, and other trace gases) in the mixture and just refer to the oxygen and everything else is assumed to be nitrogen.

EANx = Enriched Air Nitrox, which is a nitrox mixture created by adding oxygen to another gas mixture (usually air). Depending upon method used during the fill, the cylinder may be exposed to high concentrations of oxygen and may need to be specially cleaned.

DNAx = De-nitrogenated Air nitrox, which is a nitrox mixture created by removing nitrogen from another gas mixture (usually air). This is a term commonly associated with membrane gas blending systems and this method of gas blending does not require specially cleaned tanks.


To the diver, it makes little difference other than whether or not your LDS will require you to specially clean your tanks.

 

[Kim]

BS? Hardly.

It's quite interesting to see that you appear to be somewhat anti - nitrox. Might I enquire why? I ask because sometime ago there was another thread on Nitrox where the general consensus was that especially for older divers (I'm 52) it was definately a benefit.

 

[RichLockyer]

I am listed as a beginner diver on here.. But I have 41 dives, 25 of those in a dry suit, 3 of them are wreck dives

That is a beginner diver.
You may be more advanced than SOME divers with only 41 dives, and are certainly more advanced than someone who has ONLY done 41 tropical dives to 50ft, but 41 dives is not a lot of experience.

If we were to meet, I'd still dive with you though, unless your attitude on the boat indicated otherwise

 

[RichLockyer]

It's quite interesting to see that you appear to be somewhat anti - nitrox. Might I enquire why?

There are a few practical drawbacks to nitrox.

Among the impractical drawbacks, I'd consider OTU/CNS issues. A typical recreational diver is not going to run into issues with them, except perhaps on a 10-day liveaboard. The bottom time limitations of an 80 and the relatively conservative max PO2 pretty much nullify these issues. They DO become critical for deco divers who may spend an hour on pure O2.
That said, do not ignore them, as they can kill. Track your OTUs and CNS exposure if you're doing more than 8-10 dives over a 5 day period or if you're pushing your MODs.

Okay... practical drawbacks:

1 - Cost.
Air is cheap. Air-compatible tanks are cheap.
Some will argue that tanks need not be O2 cleaned, but regardless, that call is up to your shop. If your shop requires an O2 clean tank and a bumper sticker, you're going to need it.

2 - Availability.
There are only a few sources of nitrox in my GENERAL area (by general, I mean within 40 miles). One is the wrong way from my buddy's boat. One is right around the corner, but I refuse to spend my money at that particular shop. One can't fill beyond 3000 (and it's always a hot fill too!). One charges DOUBLE what everyone else charges (trying to pay for the membrane system?). Another requires an overnight stay for all nitrox fills "to let the gasses mix together for a proper analysis"... ya... the BS detector hit the roof with them.

3 - MOD.
This is where OTU/CNS can become issues REEEEL quickly if you're not careful. Why not dive below 130 on air? Well... narcosis, NDL limits, tank capacity... ya... there's a lot of very good reasons for staying above 130, but none of them, in and of themselves, life-threatening (they may lead to a bad situation though).
Bring nitrox into the picture. Why not dive below 130 on EAN32? You stand a high probability of dying. Analyze your gas, and know the two important depths... PO2 1.4 and 1.6... plan your dive, dive your plan, and DO NOT violate the 1.4 MOD unless an emergency requires your presence, and in that case, NEVER violate the 1.6 MOD.
A diver who has a difficult time controlling his buoyancy has no business diving nitrox mixes within 30 feet of their MOD.

4 - "PITA factor"
Properly diving nitrox can be a bit of a chore. You SHOULD own your own analyzer, and it needs to be used before every dive. I even analyze tanks that I know to have air in them. I'd rather a) be sure that it's really air and b) not break the habit. I don't care what the duct tape on the valve says, all of my tanks are analyzed as soon as the reg is mounted, and before they are mounted to my BC.
Of course, the analyzer is not free (though you CAN build one for $100 if you know which end of a soldering iron not to touch), and it needs to be cared for and maintained. It goes without saying that electronic equipment must be carefully cared for around salt water

5 - Benefit
Not really a drawback, but the above 4 items may not be worth the hassle for certain profiles. Your greatest benefit from nitrox is in the 60-90 foot range. Above 60ft, your bottom time is going to be limited by your air supply. Even on air, it is unlikely that you will bump up against your NDL except perhaps on a 3rd or 4th repetitive dive.
Deeper than 90 feet, you're only looking at a few extra minutes advantage offered by nitrox.

6 - Best Mix Fallacy
Some instructors/shops/divers follow a "best mix" rule. If the dive is planned to 80ft, then a mix that carries an MOD of 80ft is selected. If the dive is planned to 110ft, then a mix that carries an MOD of 110ft is selected.
Why is this problematic?
Refer to #5. Given the limited supply of gas available, will running EAN40 give ANY bottom time advantage over EAN32? I'd be willing to bet that many divers would run out of gas before they bump up against either NDL, and the NDL is not THAT different. The advantage of EAN32 is that it reduces the O2 exposure, reducing CNS/OTU concerns.
I used to dive "best mix", but it got expensive... I'd head out with a tank of air, a tank of 32, and a tank of 36 or 40. For some reason, the shallow dive would get called and I'd go home with a tank of 36 or 40. Next weekend, my buddy would call up and want to plan a trip where the most shallow dive could not be done safely on 36 or 40. Do I leave the tank at home and tell him I'm only doing 2 dives? No... I dump $10 down the toilet and refill the tank with 32.