Are there formulas for Blending Nitrox and how to achieve a certain percentages?

[lowviz]

baue has a handy z factor table available if you want to calculate it out by hand. i imagine the software packages already compensate for it automatically though.

BAUE Z Factor Table

It is a continuous function of absolute pressure. Lots of look-ups and single point approximations, but nobody (but the Navy) seems to have it.

Do the calcs, the correction is significant. In fact it is so significant that it is keeping Kev silent...

OK, in retrospect, I'll give runsongas full credit for that table. Running it through TableCurve2D produces an equation that is damn close. Close enough that I'm using it...

 

[kr2y5]

There is no reason to know how to do this unless you plan to blend your own nitrox.

Hmmm, by following this line of reasoning, there's no reason to watch news on TV unless you plan to change the course of world events... to the contrary, I think intellectual curiosity and thirst for knowledge, even if detached from an immediate application, are generally a good thing. I always find it strange how on ScubaBoard people are discouraged from asking questions...

 

[RJP]

Hmmm, by following this line of reasoning, there's no reason to watch news on TV unless you plan to change the course of world events... to the contrary, I think intellectual curiosity and thirst for knowledge, even if detached from an immediate application, are generally a good thing. I always find it strange how on ScubaBoard people are discouraged from asking questions...

Pretty sure John simply meant "don't sweat it if you don't get it" rather than "this information is shared on a need-to-know basis only."

 

[Kevrumbo]

You certainly glossed over that one, sir. So exactly what compressibility factor are you using for nature's second element???


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If compressibility is that important for your applications, then you Sir may use whatever significant "fudge" factor you need, like for example, say 10% less the ideal gas calculation calls for (see bottom p.35 of Vance Harlow's Oxygen Hacker's Companion as it applies to adding O2 first in mixing a Trimix Blend).

 

[kr2y5]

Pretty sure John simply meant "don't sweat it if you don't get it" rather than "this information is shared on a need-to-know basis only."

I'm not here to crucify John, especially as I consider John a wonderfully positive character, it is just worrisome that a lot of well-intended posts, driven by a concern for safety, add up to this unfortunate "don't ask, take a class or seek advice from a professional" vibe. I had expected that as an educator, John would rather say something along the lines of "I'm glad you asked...", and I felt disappointed that this was not the case.

I wholeheartedly second the recommendation of Oxygen Hacker's Companion, I felt it was much more informative, and fun, than any of the Nitrox courses I've taken.

 

[MaxBottomtime]

Technical Diving and Recreational - Nitrox Calculator

Nitrox Blending Calculator

 

[NAM001]

Personally I hate all the formulas expecially for nitrox. I had to find my own way to do it so i could remember it. but i am a visual guy and can draw a picture/graph representation of mixing and know it beter than the formulas.

 

[lowviz]

I like the visual approach, too.

Doing it all with a calculator gets annoying when transfilling as the order of fill is important, lots of trials have to be made to find the very best way to get what you want. The program I wrote allows you to just spin the dials using the mouse. The solution is dynamic and you can immediately see how changes affect the result. Easy.

Trouble is, it runs on one of the really old LV engines, 8.2 I really need to update it so others can use it...

 

[SubAquatix]

Dive Shop Utility Software

 

[boulderjohn]

Hmmm, by following this line of reasoning, there's no reason to watch news on TV unless you plan to change the course of world events... to the contrary, I think intellectual curiosity and thirst for knowledge, even if detached from an immediate application, are generally a good thing. I always find it strange how on ScubaBoard people are discouraged from asking questions...

Pretty sure John simply meant "don't sweat it if you don't get it" rather than "this information is shared on a need-to-know basis only."

I'm not here to crucify John, especially as I consider John a wonderfully positive character, it is just worrisome that a lot of well-intended posts, driven by a concern for safety, add up to this unfortunate "don't ask, take a class or seek advice from a professional" vibe. I had expected that as an educator, John would rather say something along the lines of "I'm glad you asked...", and I felt disappointed that this was not the case.

I wholeheartedly second the recommendation of Oxygen Hacker's Companion, I felt it was much more informative, and fun, than any of the Nitrox courses I've taken.

It is true that my response was intended as Ray took it--there is no more need for the average nitrox user to know these formulas than it is for the average automobile driver to know how the blend of gasoline is made.

On the other hand, a little learning can be a dangerous thing. If someone looks up the formulas, rents an oxygen supply bottle, and attempts to make his own nitrox without understanding the need for oxygen clean equipment and proper technique for handling the oxygen, the results can be quite unpleasant.