EAD Formulas

[Teller]

I came across a Nitrox exam and I decided to take it myself to see if it was comparable to the SSI Nitrox class I took a few years ago and to see how much I retained from the class. I came across a question asking which formula is used to calculate EAD. The formula I use was not one of the options though. I tried the three that were given and I couldnt get any of them to work out properly for me. Can someone tell me if I am missing something or is the test wrong.

Here is the formula I use to calculate EAD

(depth + 33) x FN2 / 0.79 -33 , this is how I was tought and it seems to work out just fine every time I use it.

Here are the three formulas that were possible answers on the test

((FN2 / .79) X(D / 33)) - 33

((FN2 / .79) X (Dfswa)) - 33

( (FN2) X (D/33) ) - 33
-----------------
.79

or all of the above

Can any of these be used to calculate EAD? Thanks

 

[MX727]

Your formula is correct.

The first and third formulas are the exact same and are incorrect.

The second formula is correct if Dfswa = (D+33). In this case then, Dfswa is Depth feet sea water absolute. That may be defined in the text of the source from which you gathered the quiz.

 

[Simon-]

For metric, substitute the 33 for 10

(D+10) x FN2 / 0.79 -10

 

[DevonDiver]

EAD Formula:

 

[Sir Barfalot]

In relation to the original post on formulas I recently decided to go online to complete a TDI advanced nitrox course thinking i would save some time and even a bit of cash only to drive myself nuts trying to make sense of some of the calculation errors on the site
Never again i will stick to the classroom the feedback from a live instructor is of far more value than the few bucks saved and errors in the system can be solved on the spot