Should you be diving NITROX if you can not answer these questions?

[ScubaSteve]

Steve, we might have to agree to disagree here. I made no assumptions about the person's dive plan and whether they were following it or not. The first post me gave a depth and a PPO2 for that depth for the mix he was using. Which is enough to figure out what mix he was using. You may be be interpreting it differently which is fine. Regardless though the rest of the questions from the second post should be something that someone trained in using using nitrox should know. Which is really my point.

Deal. Interpereted that way I agree that you have what you need.

 

[TheScubaBOB]

I understand how the formulas work.

In the few hour course they really didn't hammer the physics of it into our heads. I'm the kind of person who always seeks more than I'm given when I'm interested in a subject.

I will get myself a better understanding of it all in due time. I agree that it's always better to fully understand the "why" behind the limits than to just know that if you exceed then you'll likely succumb to Oxygen Toxicity.

Having said that, I'm not rushing out to dive Nitrox but I do have the knowledge to fixure what Mix I should get based on the dive plan and if the mix tests differently then will I need to adjust the dive plan to be safe.

Finally, the "Special Program" is simply a back-up to the formulas & tables. I can "do the math" pull up the software and check the resulting numbers quickly. I would never dive a Mix/Plan where 2 of the 3 (formulas/table/software) didn't agree (by that I mean use one method and verify it with the other not that 2 would agree and the 3rd didn't have to)...

kyphur,

If you were taught properly you should be able to figure things out without a special program. If you understand things it should just all make sense. It is not about memorizing formulas. I never remember the formulas. I remember the physics behind it and create the formulas from that knowledge.

If the formulas don't just make sense you should go back to your manuals or instructor and figure it all out. It really is easy to remember if you understand why things are the way they are.

Darrell

 

[lamont]

Ah, context... I only think in terms of recreational diving because that is the limit of my skills. Tech divers do all kinds of strange things. Far above my pay grade...

Well, GUE has a recreational curriculum and is trying to develop it more, and I think they may come out with a recommendation for 1.2 for recreational dives. There is a larger context there ( they error on the side of consistency between recreational and technical training with technical training taking preference ).

I recall the 2.0 number from my NAUI training in '88. It put a depth limit on diving with air - somewhere around 280 feet. I wasn't planning to dive that deep so I put the number in the 'I don't need to know this' bin.

Richard

Yep.

I'm just trying to point out that the OP shouldn't necessarily assume ignorance of nitrox, but it could just be older training. The 1.8/2.0 limits I'd be willing to argue with an "older" diver that the "newer" ways were better and that those limits are an unacceptable risk. With someone trained for 1.6 @ 130 fsw on 32%, its probably not as clear. At those depths in rec diving you're not running 1.6 for very long and its similar to what tech divers do on decompression, so if your workloads on the bottom are reasonably low, then it is arguable that its still within acceptable risk limits -- but nobody teaches 1.6 as MOD on the bottom anymore. And I wouldn't recommend it, but divers that make that choice aren't necessarily just ignorant.

 

[scubadiver888]

I understand how the formulas work.

In the few hour course they really didn't hammer the physics of it into our heads. I'm the kind of person who always seeks more than I'm given when I'm interested in a subject.

I will get myself a better understanding of it all in due time. I agree that it's always better to fully understand the "why" behind the limits than to just know that if you exceed then you'll likely succumb to Oxygen Toxicity.

Having said that, I'm not rushing out to dive Nitrox but I do have the knowledge to fixure what Mix I should get based on the dive plan and if the mix tests differently then will I need to adjust the dive plan to be safe.

Finally, the "Special Program" is simply a back-up to the formulas & tables. I can "do the math" pull up the software and check the resulting numbers quickly. I would never dive a Mix/Plan where 2 of the 3 (formulas/table/software) didn't agree (by that I mean use one method and verify it with the other not that 2 would agree and the 3rd didn't have to)...

I'm just saying, when I read the book it just had the formulas and a little understanding of WHY. Asking a lot of questions during the course made the instructor explain a lot more and relating back to the stuff I learned in Open Water (many years ago). Once I fully understood everything it was like a light coming on. Everything just was so easy. Up until that moment it just hurt my brain.

 

[Anti-Hero]

I'm hoping you're just trolling.

If you don't select an appropriate mix it could easily be your last dive.

Terry

25/25 is a perfect mix for 150'. And by most recreational definitions, if the 02 component is > 20.9% then it's Nitrox. (Semantics I know)

 

[elan]

Some snippets from another thread - all posts were made by three different people all of which are NITROX certified. The third post is mine which is combination of two posts.


First Post - "I was diving ... at 1.6 ppo (130?)"

Second Post - " ... what where YOU doing at 130 ft on NITROX? What was your %? If you planned on going THAT deep, why use nitrox? What was the benefit of nitrox at that depth?

Third Post - "Do the math, the first post contains all of the information needed to figure out the mix. As for using NITROX at 130 feet there is nothing wrong with it and the benefits to diving NITROX at 130 feet are the same and more as diving it at 60 feet. If you do not know this or can not do the math you should not be diving NITROX"

Several people did not get my post - what I found odd was that these posts were part of a larger accident discussion on this board where many people were stressing personal responsibility in the context of a person who had some knowledge but perhaps not enough to not keep/get themselves out of trouble. Yet IMHO the second post shows someone who has had the training yet still fails to have the knowledge.

So if you are nitrox certified could you answer the questions to the second post without looking them up? Please do not post the answers as they are not german to the thread and might prevent someone from realizing they need a refresher course.

I did not get your question well. The third post pretty much answered the second correct. The only thing is according to my training 1.6 ppo is too much. Other than then I see no prob diving appropriate mix even deeper. For me it looks like the second poster only have 2 (32 & 36)mixes in mind or even 1 (32).

 

[elan]

PADI Nitrox wiz-bang doesn't count.

What's wrong with PADI course ? I took it and got pretty good understanding about when I can use nitrox and when I cannot. ppo and corresponding max depth, oxygen max load and equivalent depths are pretty much covered, I can analyze the mix. what else do you need to know ?

Can you elaborate on your comment please ?

 

[Web Monkey]

25/25 is a perfect mix for 150'. And by most recreational definitions, if the 02 component is > 20.9% then it's Nitrox. (Semantics I know)

And you're telling me this why?

I'm not having any trouble selecting the right mix.

Terry

 

[pittyyofool]

PPO limits are different for every one. I can run 1.8 all day and be fine, at almost 2.0 I start getting a few small signs of TOX and I know it is time to back off a bit. On the other hand I know someone that starts having TOX symptoms at 1.6 and anther that is 2.1

ps. _____% mix is a PPO2 of 1.6 at 130fsw. did he really have that custom of a mix?

 

[Anti-Hero]

And you're telling me this why?

I'm not having any trouble selecting the right mix.

Terry

You seemed to have some kind of opposition to a 150' dive on Nitrox. A person mentioned diving to 150' on Nitrox and you asked if they were trolling, when in fact 150' dives on Nitrox is fairly common.

So why then would that poster be trolling?