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shamre · 04-28-2004, 06:07 AM,

Just wanted to know the boards opinion on breathing 100% oxygen at a depth of 15 feet or above to help increase the effectiveness of offgasing? Thoughts? Big Grin

04-28-2004, 07:15 AM,

What kinda diving are we talking? If you're thinking of adding the loaded gun to come out a bit cleaner from a rec dive I'd rather suggest doing your deep stops and slow ascent rate. If it's for a 150' range dive I'd rather add the EAN50 (or some kinda trimix with 50% O2) starting at 70ft, which gives you a much cleaner deco curve than using the O2 at 20ft. BTW, O2 is most effective being used at 20ft - shallower than that you loose some of the oxygen window benefit. If you can avoid taking O2 with you, do so - it's like carrying a loaded gun. Most technical divers get killed breathing the wrong gas at the wrong depth, and no gas has as little tolerance for mistakes than O2.

shamre · 04-28-2004, 07:19 AM,

That was exactly the kind of info i was looking for. I just wanted to be able to weigh the benefits vs. the dangers of using O2 to offgas. I had read in several tech diving books about its usage but have never personally used it myself.

DiveCaptDean · 04-28-2004, 02:29 PM,

hey shamra,

I just wanted to mention...you need certifications to use 40% O2 and then another to use 100% You may want to take a nitrox and advanced nitrox course to give you the information you request.
good luck
deano

shamre · 05-03-2004, 08:06 AM,

DiveCaptDean-taking nitrox may 11th, thanks for the info.

DiveCaptDean · 05-03-2004, 08:50 AM,

Excellent!!!! I think you will find that many of your questions will be answered. At least about Nitrox...to 40% O2...Good Luck with it and happy diving
Deano

mwenner · 01-15-2005, 05:21 PM,

Go up to IANTD's website and look through all the deco tables, and you'll see the advantages (less time spent in the water off gasing) of using 75%> O2. As soon as you own a bottle of the stuff, and start cleaning your regulator's and the bottles for O2 use you'll find out about the tip of the iceberg of information that you need to know.
IANTD or TDS (to name a few) have comprehensive Tech. courses to certify you for concentrated O2 use, and I'd highly recommend getting your information there. IANTD's Technical Diver Encyclopedia is a wealth of info in case you're considering the long journey in pursuit of this level of diving.

scubafreak · (This post was last modified: 03-25-2005, 08:20 PM by scubafreak.)

By taking the TDI Advanced Nitrox Course, once certified, you can fill your deco bottles with "up to" 100% oxygen. However, I never get mine filled at 100% oxygen, I normaly shoot for an 80% mix.

You cut down your decompression time immensely. As far as the extra bottle hanging on your BC, 40 cubic foot is a typical deco bottle size. Plenty big to last several dives, yet not to big that it gets in your way.

I do a lot of deeper diving with regular air and always carry a deco bottle.

03-27-2005, 10:41 AM,

I personally think 80 mix is a better option. You can use it a little deeper incase you have trouble with your main cylinders...

Just my 2 cents.

eric

DiverQueen · 03-22-2006, 08:58 PM,

As an Emergency Medical Technician, I would recommend that you keep the 100% O2 at the surface and use only for emergencies as in Decompression Sickness (the Bends) and in transport to your local Recompression Chamber. Breathing compressed O2 below 15-25ft has it's potential for Central Nervous System Toxicity! Yes, that can be fatal!!!! Multiply your oxygen percentage (regular air = 21%) by the number of atmospheres you dive...Anything above 1.4 -1.6 can cause CNS Tox. Use th acronym CONVENTID to look for these signs and symptoms: CONvulsions, tunnel Vision, abnormal hearing or ringing in the Ears, Nausea, Twitching facial muscles, Irritability, or Dizziness. This information is from the International Association of Nitrox and Technical Divers (IANTD) Nitrox Diver Student Manual.