EAN32 usually.. When to use EAN36

[Tom Winters]

When I read this post, I was thinking what was mentioned above - didn't the class cover the benefits of different mixtures? This is the kindofa question that given the depths involved...uh, you ought to know the damn answer if you took the course.

 

[imjustdave]

How many shops bank vs custom fill? One of my lds partial fills tanks and will blend what ever I want. They do lots of tri mix gas as well. The other banks 32 and will blend from there. Another place that I avoid banks 40 then blends but they require 24 hrs to fill a nitrox tank as they want the tank to sit before analyzing. Which just kills travel time.

 

[sportxlh]

I am fairly new and have always dove 30-70ft (other than in my AOW course) and have always just got EAN32, but I saw someone on my boat with EAN36 the other day. Possibly going to get yelled at for this but can someone just give me a quick rundown of when I would use EAN36 vs EAN32?

For me, it is anytime I'm diving above 95 feet in salt water (I want to stay at a partial pressure of oxygen or PPO2 of 1.4 or less). Most of the Jupiter sites I dive are shallower than 95 feet, but if I know I'm going to a deeper site like the deep ledge, I'll get a more appropriate mix. If I find I'm at a site that is deeper than the MOD of my nitrox mix, I realize I need to watch depth carefully while diving. I also carry a 19 cf pony bottle filled with regular air.

Quick math.......
1.4/.36 = 3.889 Desired PPO2/nitrox mix= total atmospheres

3.889 -1 = 2.889 Total atmospheres - surface atmosphere = atmospheres underwater

2.889*33 = 95.33 Atmospheres underwater X feet per one atmosphere = maximum operating depth

33 feet is one atmoshere in salt water

Hopefully you know this from your nitrox class. If not, retake the class or re-read your training manual


---------- Post added July 9th, 2014 at 11:09 AM ----------

How many shops bank vs custom fill? One of my lds partial fills tanks and will blend what ever I want. They do lots of tri mix gas as well. The other banks 32 and will blend from there. Another place that I avoid banks 40 then blends but they require 24 hrs to fill a nitrox tank as they want the tank to sit before analyzing. Which just kills travel time.

Some of the local shops like Force-E will blend any mix for you: same price no matter what (up to 40% I think). I generally use Jupiter Dive Center which banks its nitrox. Fills are usually 34-36% nitrox though the shop will raise or lower that if one desires: it just takes a couple extra minutes.

Obviously the mix in all tanks should be checked all of the time!

 

[djtimmy77]

It really isn't a big deal to get whatever mix you want at any of the local dive shops I frequent.

 

[kelemvor]

. Another place that I avoid banks 40 then blends but they require 24 hrs to fill a nitrox tank as they want the tank to sit before analyzing. Which just kills travel time.

When I go for a blend, we take the boot off and kick the tank back and fourth on the ground. Blender seems to think this helps the gas mix. It's only really a concern for my analysis since it's easy enough for him to know how much o2 he put in, and also easy enough for him to know how much air he added.

I also retest the gas with my analyzer at the dive site just to be sure. Always a good idea to know exactly what gas you're breathing.

 

[PatW]

I rarely go as deep as 95'. I have only used 32. For one thing, it is what the shops had. But the dives were boat dives with hour limits with an ascending profile so even with air I was never pushing limits. I was doing 4 dives per day and my wife chides me less when I use nitrox.

 

[taymag]

Thanks for all the answers. I reviewed my whole nitrox class last night as well as a lot on online info to clear everything up. To everyone that only answered "you should know the answer if you took the course" you contributed nothing, I don't even know why you answered. Every time I post on any forum on any subject I always learn a few things including preference based on different reasons for different situations which most of you provided. Great forum, thanks again for the replies

 

[drrich2]

I have no way of knowing why someone else does something. In the interest of perhaps helping sow some good will, I'll speculate a bit. In some places nitrox is pretty easy to get, and a lot of people consider it really benign. On the other hand, it is 'special' enough vs. air that a person ideally ought to have a knowledge base so as to have the capacity for informed consent to use it.

I think when some people saw your post, they thought you might not. Perhaps not nitrox certified, or got the cert. without really learning the material, etc..., and that you might just endanger yourslef if you didn't remedy that (e.g.: not analyzing, violating MOD & having a seizure at depth). I did not make that assumption, and tried to consider an alternative scenario where you might've simply been curious as to why someone in the real world, as opposed to in a book, might bother getting a mix that might be a bit more bother in some places.

I've seen this happen before on the forum; for some reason basic questions about nitrox tend to trigger this response. I think the intent is good, even if sometimes the delivery is not exactly warm & fuzzy.

Richard.

 

[boulderjohn]

I've seen this happen before on the forum; for some reason basic questions about nitrox tend to trigger this response. I think the intent is good, even if sometimes the delivery is not exactly warm & fuzzy.

It is actually something of a reflex among a percentage of people who use this kind of forum in general. That is one of the reasons that the New Divers and the Basic Diving forums (and now even the Advanced Diver forum) were made into what we all Green Zones. New and inexperienced divers were asking questions in hope of getting some helpful information, and they were then blasted with attacks on their mental capacity, their training, or both. It was getting quite ugly, the opposite of the friendly, helpful place that the ScubaBoard staff wants this place to be.

Several years ago, when I was still a new tech diving student, I asked a question related to technical issues with a regulator in a different forum, one that focuses more on technical diving. The regulator technicians in my shop did not know the answer, so I figured that was a good place to ask. Most of the responses were pretty insulting, and one of them, from a very well known technical diver, was about as condescending as it gets. I am now a technical instructor, and I still think it is a good question, but the know-it-alls on that other forum had to make sure that they displayed their superiority by ripping me good and hard. That experience is one of the reasons I never use that other forum any more, and I only visit it when I hear there is some interesting conversation happening there, which is less than once a year.

The regional forums are not green zones, so we do not have as much of a protective nature about them, but I hope people will remember that no one remembers everything that they were taught, and sometimes people will have a momentary lapse that leads them to ask questions they would not have had to ask if they had thought it through more carefully. As an instructor, I see this sort of thing all the time, and I sure don't blast my students for asking such questions. I try to encourage such questions instead. I hope people will think about how they would feel if they were on the receiving end of a post before they submit their responses.

 

[drrich2]

Alert - Preachy sounding post follows...

With that in mind, I have a question, again speaking generally and making no claims regarding this original poster's knowledge, training or intent.

Say someone comes to ScubaBoard, fairly new, and asks a basic question about an important matter (e.g.: how to pick a nitrox mix, deep air, solo diving early without proper training, exploring caverns with an OW buddy or doing minor wreck penetrations untrained, take your pick) which he or she should, by virtue of training, know the answer to yet obviously does not.

Say the response is hard-nosed and critical; the basic message is if you're that ignorant, you have no business seeking guidance on the matter here, shouldn't be doing that kind of diving, and need to either take the relevant course or report your instructor to his agency for lousy teaching. Oh, and you sound like a fool.

The assumption seems to be that this chastened person will actually take the course or re-train and proceed prudently.

The question: What are the odds of that, vs. just muddling along in ignorance, or asking a buddy, getting some informal and limited info. and going with that?

If there's serious doubt, what is our reaction? Darwin's gotta have somebody to play with? I can be pretty snarky and sarcastic, but these are people, not characters in a video game.

Richard.