What's your PO2?

[TSandM]

For a benign dive with little exertion, I'll go to 1.4. If I'm swimming steadily, especially if swimming hard, I prefer 1.2. Because I rarely go below 100 feet without helium, it isn't an issue.

1.6 for deco.

I base those decisions on the fact that there have been very, very few reported cases of toxing at or below 1.4.

 

[Chris Brown Tech]

Seems like a lot of people like the "1.4 PPO bottom, 1.6 PPO on deco". Is that because it's a fairly often used, well known set of parameters with which people are comfortable?

Yes, 1.4 for 'working' and 1.6 for deco is the standard in tech diving. 1.6 is the baseline, above which most agree you are in unknown territory. Even though OxTox has been observed at 0.5ATA, so its not watertight.

IANTD teaches up to 1.5 for shorter/shallower stuff where exposure time is not an issue

Are there any of you that does your loading calculations during the dive and deliberately choose your PPO according to the gradient? I know many advanced dive computers let you plug in your M-values.

On a CCR you mean? You could only do this by gas switching on OC.

Anyway, on the rebreather the setpoint of PP02 is usually constant and often lower than on OC. I can make my ascent time lower if running in manual mode by increasing my average PPO2, but Ill never exceed 1.2 on the bottom and it only saves a few minutes here and there.

I dont know anyone that has a computer where they are adjusting the algorithm underwater by entering m-values.

 

[PfcAJ]

I'm a fan of 1.2-1.4ish (maybe less) for the bottom portion of the dive. This gives me enough wiggle room to go a bit deeper if need be, but a conservative enough ppo2 to up the deco gas % to accelerate the deco to a reasonable time.

DCS is fixable, toxing is not. I'd rather err on the side of conservative with regards to ppo2.

 

[Hollywoodivers]

1.4 to 1.6 for recreational . No Toxing please.

 

[ajduplessis]

Bottom gas PPO2 of 1.5 where there is a physical bottom (floor) for that depth
Bottom gas PPO2 of 1.4 where there is not a physical bottom (floor) for the MOD of the dive
Deco @ 1.6

Subtract 0.2 of the above mentioned PPO2 for cold and high workload dives, deco stays at 1.6

 

[Pullmyfinger]

1.4 and 1.6 for me. This is as I was trained, I'll stick to that. I live in a warm water area.
-Mitch

 

[vladimir]

.....

 

[DeepSeaExplorer]

For recreational dives with no deco, 1.6 on the bottom. 1.4 for deco dives.

 

[Tortuga68]

1.6 for deco

2.0 for bottom

 

[AndrewA]

On the rebreather 1.3.
On OC 1.4 max (but usually 1.2-1.3) with 1.6 for deco.