FO2 and PO2

[Jasoncassanova]

I've been trying to understand these two, i've had a few reads but i'm still a bit confused as to what this really is and what it's for when it's used as a feature in a dive computer?

i'm not the sharpest tool in the shed but i do get practical things easily, so i guess i just need someone to explain this to me in a very simple manner.

 

[SailNaked]

PO2 is the partial pressure of Oxygen, it is generally toxic over 1.6 as a CNS risk. also dives at this level will start to limit your day with the other O2 risk pulmonary Tox. (long term O2 tox). (depending on if you use the 90 min rule or not.)

F02 I think is the computer way of saying fraction of O2 like the percentage of O2 (32% etc.) this is fixed by the mix of the gas and is how you tell your computer what it is. it will then compute PO2 at whatever depth you go and your CNS / OXtox risk from that.

 

[Couv]

DIR-diver.com - Nitrox Class Part 1

DIR-diver.com - Nitrox Class Part 2

 

[ianr33]

FO2 is the fraction of O2 in the gas you are breathing.

Air has an FO2 of 0.21. It will always be that number at any depth.

PO2 is the partial pressure of Oxygen.It changes with depth.
On the surface air has a PO2 of 0.21. At 33 feet (2ATM) it will have a PO2 of 0.42 and so on.

In recreational diving PO2 is kept below 1.4.

 

[ianr33]

PO2 is the partial pressure of Oxygen, it is generally toxic over 1.6 as a CNS risk. also dives at this level will start to limit your day with the other O2 risk pulmonary Tox. (long term O2 tox). (depending on if you use the 90 min rule or not.)

This is a garbled mess.

There is no such thing as "pulmonary Tox". (Tox is divers shorthand for "seizure")
pO2 of less than 1.6 is also a CNS risk,depending on how long you are subjected to it.

Please post more clearly

 

[PfcAJ]

Tox is shorthand for toxicity... what do you call what happens to the lungs when exposed to oxygen for long periods? Seems like everyone else (researchers, dive lit, and even wikipedia (gasp!)) uses the term pulmonary toxicity as well.

 

[ianr33]

So if I say I "toxed" on a dive what type of toxicity am I talking about?

 

[fnfalman]

So if I say I "toxed" on a dive what type of toxicity am I talking about?

If you suffer from ox tox, that means you have received toxicity from eating meat contaminated with Mad Cow Disease.

 

[fire_diver]

Tox is shorthand for toxicity... what do you call what happens to the lungs when exposed to oxygen for long periods? Seems like everyone else (researchers, dive lit, and even wikipedia (gasp!)) uses the term pulmonary toxicity as well.

Pulmonary Oxygen Toxicity is a complete non-issue for divers. You can't dive oxygen long enough to create a problem. Pulm OxTox is a long-term health care issue affecting people who breath O2 all day, every day.

 

[ianr33]

Pulmonary Oxygen Toxicity is a complete non-issue for divers. You can't dive oxygen long enough to create a problem. Pulm OxTox is a long-term health care issue affecting people who breath O2 all day, every day.

While I agree that is true for 99.999% of divers it CAN be a problem for rebreather divers doing long dives day after day.