Which expert is right? re:Nitrox on air tables

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del_mo

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Being of an "advancing" age, I wondered about getting nitrox certification and then diving air tables to remain ultra conservative. I understand the depth limitations of nitrox, so that doesn't play into this question.

I asked two experts the same basic question. Both experts have enough certifcations to wallpaper the orange bowl. But, they couldn't disagree more on the answer.

One expert said the extra safety of diving air tables on nitrox isn't worth the expense of getting that level of certification. The reason to get nitrox certification is for "more bottom time". The other said it is an excellent idea that will help reduce the chances of getting DCS.

One also went on to say the PADI dive tables for mutiple dives are among the MOST aggressive (as opposed to conservative) tables there are. He recommended using the DCIEM tables or getting a dive computer that uses the DCIEM model (he liked Suunto).

Any other opinions or thoughts?
 
I don't have any medical experience to offer you a definitive answer. But generally I can't see how Nitrox on air tables could hurt, even the doctor who didn't recommend it only seemed to do so on "the expense". As for the PADI tables, the RDP and wheel were developed by PADI DM Dr. Raymond E. Rogers in the early 80's and have their basis in the U.S. Navy tables. Rogers, working with DSAT, tailored the Navy tables (reducing surface intervals, deco times) to creating a more accomodating table for recreational diving. It is therefore more aggressive than the Navy tables but only because recreational divers are not diving to the same profiles as the navy tables would be set for.
 
del_mo:
Being of an "advancing" age, I wondered about getting nitrox certification and then diving air tables to remain ultra conservative. I understand the depth limitations of nitrox, so that doesn't play into this question.

I asked two experts the same basic question. Both experts have enough certifcations to wallpaper the orange bowl. But, they couldn't disagree more on the answer.

One expert said the extra safety of diving air tables on nitrox isn't worth the expense of getting that level of certification. The reason to get nitrox certification is for "more bottom time". The other said it is an excellent idea that will help reduce the chances of getting DCS.

One also went on to say the PADI dive tables for mutiple dives are among the MOST aggressive (as opposed to conservative) tables there are. He recommended using the DCIEM tables or getting a dive computer that uses the DCIEM model (he liked Suunto).

Any other opinions or thoughts?

They are both right (sort of) Diving nitrox on air tables is a way to increase the conservatism of the table. Not a bad idea for us over 40 crowd. You may also use nitrox to increase bottom time but then you loose the conservatism.
The DCIEM table are not used in Suunto computers nor any others that I am aware of. Almost all are using some form of Buhlmann algorith, even though Suunto claims RGBM it is not a true application.
The best nitrox training available in my opinion is the ANDI CSU course. It teaches the most varied applications of nitrox usage up to 50% mix.
Hope that helps and I would definately get some nitrox training and then use the application that suits your needs.
 
del_mo:
Being of an "advancing" age, I wondered about getting nitrox certification and then diving air tables to remain ultra conservative. I understand the depth limitations of nitrox, so that doesn't play into this question.

If you want to dive more conservatively than the tables then dive more conservatively than the tables. Reduce the NDLs by 10%, 20%, whatever, and use that as your limit when planning. That makes much better sense than taking whatever reduction you get from using the wrong table, and it leaves you in a much better position to evaluate the possible consequences if things don't go according to your plan.
 
As a Nitrox Instructor I have come across this issue many times in the past. It has been discussed by many others, and there are a few points I'd like to mention from the concensus reached.

The advantages in diving Nitrox have been mentioned, so I will not repeat them. However, as an older diver, it is a further advantage to breathe an enriched mix that is kinder to your tissues, that will leave you feeling fresher after diving, and will in itself be an aid against DCS.

Using air tables is a common way of increasing conservatism, and if it makes you feel good to do it this way, then do.

US Navy tables had a 6% failure rate, Buehlmann has 1%. DCIEM is also ahead. My advice is go for a table/computer that is based on a rate of ascent of not more than 33ft/min.

If you base your decision, IMHO, to do the Nitrox course purely on economics, then you are denying yourself of a safer option in diving. Bottom line is Nitrox is a safer gas to use, within it's limits.

Instead of using air tables you might try a "middle of the road" approach, and decide on a PPO2 limit of 1.4, as opposed to the usual max. of 1.6. Then you would be gaining maximum advantage, economically as well. If you want to be more conservative, then make it 1.3!

This will dictate the depths and times you can go to, and your feelgood factor should improve as well.

Experts differ in opinions, but should agree on facts.

The fact is, you want safer diving - a built-in safety margin - and Nitrox can offer this.

Enjoy!!

Seadeuce
 
del_mo:
One expert said the extra safety of diving air tables on nitrox isn't worth the expense of getting that level of certification.

Hmmm....Lets see....

The cost of the cert is what...$100?

So, the extra safety isn't worth $100? What about the extra knowledge, the flexibility, etc.

I guess you can tell that I prefer extra knowledge and the flexibility that comes with it.

Get the training...
 
The class is a good on e, it wont hurt it will help.
 
Charlie99:
Slight thread highjack ..... Actually, the Aqualand series of dive computers by Citizen use the DCIEM model. Here's a good summary of DCIEM's series (as opposed to the more common parallel) dissolved gas model.
Thanks Charlie, now I am aware of one.
 
https://www.shearwater.com/products/swift/

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