PADI Enriched Air Certification.... a little fishy.

[billgraham]

That is true but playing devils advocate a bit, how deep can you actually breathe a 100% mix......i'd be willing to bet you can make a switch from your back gas to 100% at 30ft and make it to 20ft without incident. But then again if im being very conservative maybe my MOD for oxygen would not be 20 because I maybe want to keep a pp02 of 1.2 or less.

You can breathe any gas at any depth........doesn't really mean its a good idea.....the MOD is really just a guideline that experiments in diving has told us is possibly a safe depth (i say possibly because since everyone is different, what works for me may ox tox or bend someone else)

IMHO conservative is the best way to go but when the $**t hits that fan, im not gonna feel bad about breathing a gas a few feet below its marked MOD



at the end of the day i guess what Im trying to say is you have to have an understanding of how the gas works and why MODs are what they are.....not just following a chart blindly

Yeah, I'm talking more about the protocol for marking tanks, most use the 1.6 number.

 

[FoxHound]

yeah 1.6 is pretty well the standard.....im pretty sure industry wide recognizes 1.6 as a pretty safe ppo2 for the majority.

 

[rhwestfall]

actually NAUI uses 1.4 as the standard for calculations, and a 1.6 contingency - yes its conservative, but the agency tables are too in comparison to the US Navy set....

 

[mala]

anywhere from 1 to 1.4 for bottom gas.

1.6 for deco .

 

[boulderjohn]

yeah 1.6 is pretty well the standard.....im pretty sure industry wide recognizes 1.6 as a pretty safe ppo2 for the majority.

That's not my experience.

I have dealt with several agencies. Each one recognizes 1.2-1.4 as the limit for active diving and 1.6 as the limit for decompression.

 

[FoxHound]

i like 1.2 for back gas,......deco gas is 1.6 and yes you are right, i meant to mention 1.6 for deco and 1.4 for back gas, guess that's what happens when the wife rushes me out the door to go get paint while im writing

 

[gcarter]

Yeah, I'm talking more about the protocol for marking tanks, most use the 1.6 number.

I was taught to mark the tank 1.4 MOD / 1.6 MOD, or planned MOD / contingency MOD. Example for EAN32 would be 111/132 or 34/40 in metric.

 

[CaveMD]

I was taught to plan my dive with cns% in mind and reduce the ppO2 as necessary for the profile. For example, doing a 30-45 min dive at 100ffw on 32% is fine. If I do one of my 2hr+ bottom time dives in little river cave at 100' on 32% that is just too hot for me and I will dial the o2% back accordingly. I would rather save my cns for 100% o2 deco.

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[hypertech]

I was taught to plan my dive with cns% in mind and reduce the ppO2 as necessary for the profile. For example, doing a 30-45 min dive at 100ffw on 32% is fine. If I do one of my 2hr+ bottom time dives in little river cave at 100' on 32% that is just too hot for me and I will dial the o2% back accordingly. I would rather save my cns for 100% o2 deco.

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2 hr bottom times at 100' is well beyond recreational nitrox, which is where I think this discussion has been centered.

 

[CaveMD]

2 hr bottom times at 100' is well beyond recreational nitrox, which is where I think this discussion has been centered.

The last 10 or so posts have mentioned deco.


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