Diving Nitrox with Computers?

[syntaxerrorsix]

Thanks for the english lesson. I wasn't aware that anyone had stated that 'max meant only'.

What had been said was that divers could make a "personal decision on allowable ppo2". That, to me, seems like a very different statement to making a "personal decision on conservatism within recommended ppo2 limits".

Other than randomly adding conservatism...exactly how is a recreational diver educated to calculate a personal max ppo2?

By using a fixed set point and reducing the pO2 based on conditions of the diver and the water. That to me says there is flexibility in the diver's use of a lower pO2 and NAUI does in fact teach it.

After re-reading the posts I do agree with your assessment in regards to "allowable ppO2" if it equates to increasing the range passed a 1.6 and I noted that exception in my previous post. That's not how I interpretted the post you were referring to however.

 

[DevonDiver]

Really?

In what increments? On what scale?

Are you making this up? Or is this an agency advocated system?

 

[Jax]

driebel, I do not know why your computer specifically shows the O2%, but I can say that ever computer I've looked at also displays the O2%.

I surmise it is because it (okay, the programmer) wants YOU to know your parameter is set at that O2%. As a diver, you are expected to KNOW your mod . . . knowing that the computer is set to a certain O2% reassures you that all the calculations and alarms are set for that O2.

Again, my SWAG on the 'why'.

 

[Jax]

By using a fixed set point and reducing the pO2 based on conditions of the diver and the water. That to me says there is flexibility in the diver's use of a lower pO2 and NAUI does in fact teach it.

After re-reading the posts I do agree with your assessment in regards to "allowable ppO2" if it equates to increasing the range passed a 1.6 and I noted that exception in my previous post. That's not how I interpretted the post you were referring to however.

Really?

In what increments? On what scale?

Are you making this up? Or is this an agency advocated system?

 

[syntaxerrorsix]

Really?

In what increments? On what scale?

Are you making this up? Or is this an agency advocated system?

Chapter 4 NAUI NITROX Manual states "For recreational nitrox diving, the MOD should be derived from the recommended maximum oxygen partial pressure of 1.4 ata but it can be calculated for other partial pressures as well.


Example 2 "You receive a cylinder that contains EAN33 and you choose to dive a more conservative partial pressure of a 1.3 ata. to find your MOD read across........"

So yes, it discusses building in conservatism, a well known and specific example is the nitrox diver using air tables. The scale printed in the book ranges from 1.2-1.6 for a quick reference but it teaches all the basic calculations.

No I'm not making it up, thanks though.

 

[DevonDiver]

I think we're talking at cross purposes..

Obviously, the book/table will give a variety of PPo2 options. Every agency does that.

I was asking (in line with earlier posts) if there was a scale that enabled divers to calculate a specific reduced ppo2. THAT is what I thought you were alluding that NAUI did...

for example:

Normal = 1.4ppo2

For each factor, reduce 0.1 ppo2; cold, exertion, obesity, fatigue, current, bad viz etc etc

 

[Mr Carcharodon]

The FO2% is there to tell you if you have entered the values correctly or not. It is very common for people to be diving nitrox and leave the computer set to 21%. Max depth is there since some people still dive tables and you need that bit of information. I agree that it would be nice if some of the fields were user settable. That may have to wait for version 2.0.

 

[syntaxerrorsix]

I think we're talking at cross purposes..

Obviously, the book/table will give a variety of PPo2 options. Every agency does that.

I was asking (in line with earlier posts) if there was a scale that enabled divers to calculate a specific reduced ppo2. THAT is what I thought you were alluding that NAUI did...

for example:

Normal = 1.4ppo2

For each factor, reduce 0.1 ppo2; cold, exertion, obesity, fatigue, current, bad viz etc etc

No, just basic rules of conservatism and when to apply them which in my opinion allows for the flexibility we were discussing. Nothing more.

Without getting in a semantic debate about personal freedom... I don't think any agency teaches a flexible system of ppo2.

 

[Damselfish]

The Vyper in Nitrox mode will revert from whatever you're really diving to 21% if you haven't been diving enough. The purpose of the % display is so you can notice during your dive that the @!#&$ thing has changed back on you (again) and there's not a darn thing you can do about it. (tongue firmly in cheek)

 

[Mr Carcharodon]

Deleted duplicate post (stupid mobile devices).