Would you dive if you flew out within 24 hours?

[freewillie]

It is going to be a judgment call depending on your tolerance of risk. The more risk averse you are the more conservative your allowance for time.

One of the general rule's of thumb the closer to the cutoff the higher your chance DCI. Is it a big risk? Probably not but is still higher than a more conservative approach.

I am pretty conservative by nature, hence my more conservative recommendations. Others have opined the recommendations are safe at shorter interval.

As with lots of decisions, get advice both sides of the coin then make your own informed decision.

 

[Tigerman]

The OP should make an arbitrary decision, rather than a rational one?

Youre not asking for rationalization, youre asking for a discussion about completely hypothetical, irrelevant scenarios..

 

[japan-diver]

If you have actually read the DAN report on flying after diving you would see that there recommendations have quite a bit of conservationism already in place. The scenario in question exceeds these recommendations by over 6 hours. The 24 hour rule was very loosely based on science and some broad assumptions based on what we knew about DCS at the time - the DAN study was the most complete scientific study done on the subject that I can find anywhere. Go do the dive, enjoy it and relax. You are well over established minimum surface intervals and the risk of the flight causing a problem is miniscule, almost non-existent if you look at the how fast you will completely off gas from a single dive of the type you describe. I would bet that if your dive computer actually has a desat option it will show you clear of all nitrogen in about 10 hours or less on a dive that you describe.

 

[vladimir]

Youre not asking for rationalization, youre asking for a discussion about completely hypothetical, irrelevant scenarios..

I don't want to argue. You should read the very short article I linked to in post 4. It will help you put the risk in perspective and improve your flying-after-diving decision making.

 

[DandyDon]

As per DAN recommendations 24 hours...

Nope, incorrect, not true, changed over a decade ago but the rumor persists.

this answer is right on point

And wrong.

 

[rick00001967]

"a minimum surface interval of 12 hours is required to be reasonably assured a diver will remain symptom free upon ascent to altitude in a commercial jet airliner pressurized to an altitude of 8000 feet"
"a surface interval of 18 to 24 hours is recommended after daily multiple dives over several days or dives that require decompression stops. the greater the surface interval before flight the less likely DCS will occur.
"DAN makes the point that there can never be a flying after diving rule that is garanteed to prevent DCS completely. rather, there can be a guideline that represents the best estimate for a conservative, safe surface interval for the vast majority of divers. there will always be an occasional dive whose physiological makeup or special diving circumstances wil result in DCS."

this was taken directly from my SSI training course material that i am currently studying......decide for your self

i think the bottom line in any diving situation, including this one, is this........first and foremost.......always dive within your training limits and your own comfort zone. never follow someone else recommendations. especially if they are basing those decisions on advanced level training that you yourself have not taken.
is it ok for a fully trained cave diver to enter the "no light zone" to explore an area of a system that is off limits to most of us ?? based on their training and experience, probably "yes". at least they have made a calculated decision on what risk level they are comfortable with. but is it also ok for me as an open water cert diver to follow that same cave diver into that same area if he says to me....."it's ok. just follow me and you will be fine." i would think we could all agree that answering "no" to that scenario is the only answer.
maybe my point is a bit dramatic but the issue is the same. my training up until this point has always been to wait 24 hrs before flying after any diving. and that is what i do. period !! now perhaps once i complete my current training and understand better how nitrogen absorption and off gassing really works at a physiological level, i might decide that i can reduce my no fly time to 18 or even 12 hrs depending on my situation. but as of right now, i am a typical average recreational diver. and my training and comfort level tells me to wait 24hrs. the OP should follow their training and do what is comfortable for them. imo, if they are asking the question, they already know the answer. i say this in my real job at home all the time to the new guy i am training........if you have to ask, "should i be doing this ??"......then the answer is always NO.

so to the more advanced divers here on the boards......i think it is great to share your knowledge and experience with the rest of us so the dive community here benefits from it. but please remember that not every one fully understands the science or theory behind a lot of your decisions. so even though you may be technically correct in advising the OP it is ok for them to have an SI of a shorter duration, keep in mind the point i have tried to make.

 

[robbcayman]

Just because you can't calculate precise odds does not mean that all risk assessment is futile. You can create a hierarchy of risk. If, for example, flying after a single NDL dive and an 18-hour surface interval was less risky than 55-minutes at 60 feet and no flying*, would your view change? Or is that dive too risky for you as well?

*not a claim, just a hypothetical

I never said that risk assessment is futile, but that it is hard to calculate the odds as the variables are unknown. Most agencies also allows for computer diving and many people have followed conservative computer algorithms and still gotten bent. Just because an agency says it's okay or suggested doesn't mean it's a guarantee to not getting bent. Hence, it may be wise to go a little bit further past their suggestions to further safeguard against getting bent, but that decision is up to each diver. It's an inexact science due to the aforementioned reason that everyone's body is different. Some may hold nitrogen in their tissues longer than others while some may off gas extremely quickly. I fail to see the harm in playing it safe and adding a few extra hours before you fly out.

If you want to fly out after however many hours then go for it. I'm not the scuba police and I'm not trying to tell people what to do. I was only giving the OP my opinion and my reasoning for doing so.

 

[vladimir]

From that one-page article that nobody wants to read:

You could decide to wait for 12 hours before your flight, and have an estimated 1 percent risk of Definite DCS and approximately 2 percent risk of Ambiguous DCS. If you want to keep your level of risk at zero, then don't dive or don't fly. Every time you dive, you are subjecting yourself to a risk of DCS. No tables guarantee absolute safety.

In making decisions about risk, you can look to existing guidelines and practical experience for clues, such as the 12-hour flying-after-diving guideline. The estimated DCS probability for this surface interval is about 1 percent. Another clue is the estimated probability for a 55-minute dive to 60 feet. The estimated risk of DCS is 0.5-1.0 percent for this dive. We have far to go before we are comfortable with our estimates of DCS probability, but the information we've gathered thus far is already making decompression safety less mysterious.

 

[GrumpyOldGuy]

From that one-page article that nobody wants to read:

I read it, it was informative but I found it difficult to tie directly to my diving style. 1% is a risky number for me, I am not comfortable with it, but I also don't dive right to the table limits either. If I am pushing NDL, I jump to Nitrox (I am old enough not to push the limits).

What I did find interesting was this statement "Ten-, 11- and 12-hour surface intervals, however, were considered acceptable according to the acceptance/rejection rules described above. The 10-hour surface interval produced one ambiguous symptom in 23 trials, but the 11- and 12-hour surface intervals had no symptoms in 23 and 27 exposures."

Basically, I read it as they has no incidents at 12 hours. Since I don't push the NDL and I don't even push 12 hours, I feel safe. Maybe its not statistically 0 because the sample size limits, but its in the neighborhood, a small fraction of 1%. If you do the the math combining the 11 and 12 hour intervals you have 50 samples, no incidents (ambiguous or real).

 

[lv2dive]

The actual science of Decompression Illness is not well understood. One diver can get away with a 12 hr window, another diver might get bent with 18 hrs. Certain factors like age, physical fitness, hydration, cold, time and depth all play a role. It's not an exact science so you won't know until you try, but sitting on an airplane is not good time to find out you made the wrong choice.

As per DAN recommendations 24 hours best but 18 to 12 hours are the minimum.

On vacation I always give full 24 hours until fly. Gives me one full day before we leave and wife likes when spend extra time with kids.

this answer is right on point

"a minimum surface interval of 12 hours is required to be reasonably assured a diver will remain symptom free upon ascent to altitude in a commercial jet airliner pressurized to an altitude of 8000 feet"
"a surface interval of 18 to 24 hours is recommended after daily multiple dives over several days or dives that require decompression stops. the greater the surface interval before flight the less likely DCS will occur.
"DAN makes the point that there can never be a flying after diving rule that is garanteed to prevent DCS completely. rather, there can be a guideline that represents the best estimate for a conservative, safe surface interval for the vast majority of divers. there will always be an occasional dive whose physiological makeup or special diving circumstances wil result in DCS."

this was taken directly from my SSI training course material that i am currently studying......decide for your self

i think the bottom line in any diving situation, including this one, is this........first and foremost.......always dive within your training limits and your own comfort zone. never follow someone else recommendations. especially if they are basing those decisions on advanced level training that you yourself have not taken.
is it ok for a fully trained cave diver to enter the "no light zone" to explore an area of a system that is off limits to most of us ?? based on their training and experience, probably "yes". at least they have made a calculated decision on what risk level they are comfortable with. but is it also ok for me as an open water cert diver to follow that same cave diver into that same area if he says to me....."it's ok. just follow me and you will be fine." i would think we could all agree that answering "no" to that scenario is the only answer.
maybe my point is a bit dramatic but the issue is the same. my training up until this point has always been to wait 24 hrs before flying after any diving. and that is what i do. period !! now perhaps once i complete my current training and understand better how nitrogen absorption and off gassing really works at a physiological level, i might decide that i can reduce my no fly time to 18 or even 12 hrs depending on my situation. but as of right now, i am a typical average recreational diver. and my training and comfort level tells me to wait 24hrs. the OP should follow their training and do what is comfortable for them. imo, if they are asking the question, they already know the answer. i say this in my real job at home all the time to the new guy i am training........if you have to ask, "should i be doing this ??"......then the answer is always NO.

so to the more advanced divers here on the boards......i think it is great to share your knowledge and experience with the rest of us so the dive community here benefits from it. but please remember that not every one fully understands the science or theory behind a lot of your decisions. so even though you may be technically correct in advising the OP it is ok for them to have an SI of a shorter duration, keep in mind the point i have tried to make.

I'm not going to link to the article others have already linked to and discussed - DAN recommendations are 12 hours for single dives and 18-24 hours for multiple. Why this 24 hour thing persists I do not understand?!?! At any rate...

In this case... dives on Wed weren't even close to NDL's then a full day off on Thursday pretty much resets the clock... so we are looking at DAN's single day recommendations. 12 hours. And the OP is way more than exceeding that. I personally would have no concern in this case.

With regards to "the more advanced divers" advising people... this is not advanced decompression theory, this is basic OW stuff. And to clarify - I haven't seen anything in this thread that is remotely inappropriate regarding decompression theory, and can't imagine that most tech divers would get into that kind of detail in basic scuba discussions - any more than a certified cave diver is going to provide inappropriate advice here (I don't know where that came from but wanted to reference it). Most of us recognize that you need to get the training in a class.