Got a Nitrox question...?

[DandyDon]

I if I Understand DAN's suggestions about flying after diving correctly:
(1) Wait at least 12 hours - more would be better;
(2) After multiple dives, days of diving, wait at least 18 - more would be better; but
(3) None of these are guarantees - more would be better.

Okay, if I'm looking at a last dive of a trip, say 25 hours before my plane is due to take off, and my dive is planned to no more than 60 feet, would Nitrox be better than air? Would the less loading of nitrogen give me a better safety margin, and if so - would it be very significant? :huh:

Thanks, D-Don

 

[Windwalker]

Always plan for Worse case. Lets say that you want to dive Nitrox, and your max depth is 60 feet. If you were to Dive EAN40 then you would have an Air table equiv of 40 feet. your 02 loading with EAN 40 at 60 feet would be less then 1.2. 40 feet on the air tables would increase your safety margine as opposed to diving Air at 60 feet. As you would have less Nitrogen exposure. MOD for EAN 40 for a 1.4 load is 82 and for a 1.6 is 99 feet.

Even Diving Nitrox personally I would take the standard precautions, and wait the requisite time. Your adding safety.

But yea, Nitrox helps increase your safety margine by reducing your Nitrogen exposure.

The significance of diving Nitrox is 20 feet on the air tables. Now, Chances are, you won't be able to get EAN40, you will probably be stuck with EAN32 or EAN36, The latter of course would be better but your air equivelancy depth would be 50 feet.

Since your talking about using Nitrox, I am making an assumption that you have taken a course in it, and you know that exceeding the hard limit of Nitrox can lead to convulsions and death. (explaination of danger is for people who haven't taken course)

 

[DandyDon]

Windwalker once bubbled...
Since your talking about using Nitrox, I am making an assumption that you have taken a course in it, and you know that exceeding the hard limit of Nitrox can lead to convulsions and death. (explaination of danger is for people who haven't taken course)

Nitrox certified, two Nitrox computers at all times, got my own tester. :grad: The safety question is a trade-off, for while one acquires less nitrogen loading, one has to be careful of oxygen toxidity and oxygen loading. :huh: Don't understand all of it, but I respect it. If my computers - same brand - ever disagree, I go with the more conservative.

Thanks, D-Don

:iwagima:

 

[Woolf78]

I am thinking along the same lines at the moment. My problem is that my company has a new policy whereby I am not allowed to fly (as a heli pilot) for 48h after diving deeper then 10m (33ft).

We don't fly any higher than 6000ft and I always wait for 24h after diving one or two non deco dives. With these new regulations in place I can no longer dive on weekends wich is really annoying so I thought that nitrox might help with this.

My thoughts are that if I can stay at the equivalent air depth of 10m on Nitrox I can at least maybe get down to 15 or 20m without breaking the rules (too much). This combined with a 24h wait should give me all the comfort I need to go flying again and also keep the company happy.

Any thoughts, flaws or comments?

Thankx!

Woolf

 

[Doppler]

Use nitrox and yes it may make a significant difference.

The "science" of it is that you will be breathing a lower partial pressure of nitrogen compared to the same dive breathing air. Less nitrogen means a lessened risk of critical tissue loading. Of course you have to keep the oxygen loading well within the acceptable depth and time limits (NOAA seems to be the standard).

If you get the chance, another "technique" is to breath 100% oxygen on the surface immediately following the dive... 30 minutes to 45 minutes. Thinking is that this too helps off-gassing. Of course, with training, one might also add 100% oxygen to the diving toolkit and breath it on an extended safety stop at 4 to 5 meters

Doppler

 

[Windwalker]

dandydon once bubbled...


Nitrox certified, two Nitrox computers at all times, got my own tester. :grad: The safety question is a trade-off, for while one acquires less nitrogen loading, one has to be careful of oxygen toxidity and oxygen loading. :huh: Don't understand all of it, but I respect it. If my computers - same brand - ever disagree, I go with the more conservative.

Thanks, D-Don

:iwagima:

Good idea.. I would imagine that with 1.2 ata of oxygen pressure(at depth), that you should not have any problems at the surface. 1.4 is considered somewhat conservative, 1.6 is the limit (and it is considered a hard limit) because exposure to 2.0 ata of oxygen does different things to different people under different conditions. In my case, given the overall situation.. Depth of 60 feet, breathing EAN40, single dive, flight in <24 hours. Any risks of Nitrogen related issues would be significantly reduced, and any risk of Oxygen related issues would not be bad enough to be concerned about.

As for the Helicopter problem.. SUCK!! What is the Basis of the decision to limit for 48 Hours?? I was under the "Impression" based on DAN research and Navy research, that for Non-Decompression Diving 24 hours was enough to Off gas for many flights?? Also, What is the Cieling for a Helecopter? 12,000 feet? Thats what 7PSI of Air Pressure? What do commercial airlines pressurize the cabin too?

When I take the Corporate jet, the only requirement is that haven't dove for 24 hours.

 

[Dr Deco]

Dear Dandydon:

DCS and Flying

I personally believe that one truly under appreciated problems of off gassing on the surface is strenuous activity and bubble nucleation. In a laboratory, you can do wicked things with exercise to people who have all been exposed to the same profile. We have seen this time and again in our NASA studies.

Since you cannot change the dive profiles, my suggestion would be to go easy as possible when exiting the water and afterwards (for a few hours). Try and have someone help you onto the boat and take your gear. Try to avoid climbing the ladders with all of gear. Do not engage in strenuous activities following the dive (swimming, volleyball, etc).

In addition, move about some to promote blood flow, and gas washout, to the tissues.

Dr Deco :doctor:

 

[DandyDon]

I don't think I've ever read anything about avoiding strenuous exercise after diving, other than your postings. Maybe, but I don't think so.

Climbing out of the water with full gear at the end of a dive has always been a noticable challenge, and handling weights and tanks at the dock can be. I gotta' remember to avoid both when I can. The approach that comes to mind is give the ladder mate a short excuse (doesn't even have to be the true one) and an upfront tip. Of course, we see Dive Masters doing all this and more after diving with the rest of us, but (1) they're younger and in better shape, which would matter, I think, and (2) it still doesn't make it right.

I am looking to stay within DAN guidelines, plus add additional safety. I feared that my initial posting might seem silly, but now I'm glad I asked!

Thanks y'all! D-Don