EAN versus "no-Fly" delay

[caseywilson]

I already have one full layover day before flying planned into my next dive trip so please don't bother hassling me about safety — as some are wont to do.

I am planning on doing an EAN certification sometime in the future. I've read only a bit about it so far. I find it interesting that a major reason for EAN is actually to displace nitrogen in the breathing mix. That in turn reduces the risk for DCS and, under the right conditions, 'could' even make the safety stop unnecessary.

So, my question is, could it shorten, or even eliminate the no-fly restriction?

Casey

 

[redacted]

Yes, but nobody knows how much.

 

[tbone1004]

it won't eliminate, but basically nitrox can be used in one of two ways. It can be used to extend your NDL times by some amount, or it can be used to increase your "safety" by diving as if it were air. If you go to your NDL, it doesn't matter what mix you are diving, your tissues are saturated to the same level so flying after diving time isn't changed. If you dive nitrox as if it were air, you are basically diving to a shallower equivalent depth so you come out with less tissue loading and that will reduce your no fly time, but that can only be determined if you know your theoretical tissue loading and most computers don't tell you that.

 

[Chris12day]

The "safety stop" is a decompression stop. Why do we do a "safety stop"? To reduce the chance of having a DCS hit. Why do we wait 24 hours prior to flying? To reduce the chance of having a DCS hit. Why dive EAN? To reduce the chance of having a DCS hit.

Diving is all about risk management. YOU MANAGE YOUR RISK. Most of us do everything we can to reduce the risk of a DCS hit.

 

[tbone1004]

Why dive EAN? To reduce the chance of having a DCS hit.

NO
it does nothing to reduce the chance of a DCS hit if you are setting your computer to that mix. If you tell your computer that you are diving nitrox 32, and you are diving nitrox 32, and dive to NDL it has the same risk as if you were diving air and told it you were diving air. It only helps to reduce the risk if you dive EAN and tell the computer that you are diving air, or some mix that is less enriched

 

[BoltSnap]

NO
it does nothing to reduce the chance of a DCS hit if you are setting your computer to that mix. If you tell your computer that you are diving nitrox 32, and you are diving nitrox 32, and dive to NDL it has the same risk as if you were diving air and told it you were diving air. It only helps to reduce the risk if you dive EAN and tell the computer that you are diving air, or some mix that is less enriched

No, you don't have to lie to your computer and tell it that you are using a different mix, you just have to end your dive before your NDL based on Nitrox. This will give you an added safety margin against the NDL but won't guarantee anything.

 

[tbone1004]

No, you don't have to lie to your computer and tell it that you are using a different mix, you just have to end your dive before your NDL based on Nitrox. This will give you an added safety margin against the NDL but won't guarantee anything.

and how do you determine "before your NDL based on Nitrox"? you have to lie to something in some ratio of how much O2 otherwise you are just ending your dive early and diving EAN vs. air has nothing to do with that

 

[matt_w]

and how do you determine "before your NDL based on Nitrox"? you have to lie to something in some ratio of how much O2 otherwise you are just ending your dive early and diving EAN vs. air has nothing to do with that

I believe he was saying no-one is forcing you to dive to the NDL. If you set your computer to the correct mix and ascend before you reach the NDL that is adding a safety margin in a manner similar to setting your computer to the wrong gas.

 

[BoltSnap]

and how do you determine "before your NDL based on Nitrox"? you have to lie to something in some ratio of how much O2 otherwise you are just ending your dive early and diving EAN vs. air has nothing to do with that

You have to decide on how much "safety factor" you want in your dive. Most computers allow you to adjust your "conservatism" setting. With Nitrox, you can set your computer to the most conservative setting and you will have a much higher safety margin.

 

[tbone1004]

You have to decide on how much "safety factor" you want in your dive. Most computers allow you to adjust your "conservatism" setting. With Nitrox, you can set your computer to the most conservative setting and you will have a much higher safety margin.

but no more conservative than doing that same dive with the same conservatism settings on air. Conservatism settings don't care what mix you are diving. The only way to make EANx more conservative than air, is to tell your computer you are diving air, and dive nitrox. Conservatism is then increased by the difference in FO2 of your mix and air. OP specifically asked about EANx being more conservative than air, if everything is equal except the mix, i.e. same depth, same dive time, then yes it is more conservative, but if you dive to the same depth and you dive to your NDL, then it is no more conservative you just have the advantage of being able to dive longer. Nitrox 101....