I don't "administer" anything.
To
buy O2 depends on what KIND of O2 you wish to buy. Aviator's Breathing O2 is not regulated. Oxygen USP is regulated - you need a prescription for it. The two come out of the same cryo flask, but have different labels on the cylinders. They are functionally the same gas, however.
Buying a DAN O2 kit requires only money. Other suppliers may have different requirements. Filling the DAN O2 cylinders requires only a dive shop that has the proper adapter, or a friend who does and mixes his own gas. The only thing to be aware of with the DAN O2 cylinders (or any other medical-style cylinder) is that if it has an "Oxygen USP" tag on it you
must remove it before putting Aviator's O2 in there, or you are technically guilty of "unauthorized manufacturing of a prescription drug" - a federal felony! :boom: My cylinders do NOT have the tag on them
The O2-provider course is pretty much a joke, but it does have useful info contained in it - mostly centered around the precautions associated with handling Oxygen. Smoking around it is a bad idea, just as one example
If you can handle assembling hardware that is pretty obvious in its method of assembly you should be ok putting together an O2 bottle, reg, hoses and such without the class.
As for going back in the water Arnaud, that depends on the circumstances. I don't pretend to make decisions for others, but I can tell you what
my criteria is:
1. If I am diving a computer, and grabbed the O2 because I was just too close to the margins for my comfort, and after a couple of hours I'm both ok and the computers says I'm ok, then I might do another dive. In that case I breathed the O2 simply for safety margin, and not because I had "deserved" a hit due to my conduct. I do indeed add the OTUs for the Oxygen to my total exposure for the day (they're minimal, all things considered, but you should keep track.)
2. If I blew an ascent or committed some other more serious "sin" in my dive profile (e.g. blew off what was supposed to be mandatory deco underwater due to gas supply, etc) then I'm done for a couple of days. (I've never been in that situation.) In that case I had a "deserved" hit that I avoided - and in that case I am unwilling to take the chance that I might get the hit anyway while underwater!
In the one case that someone HAS grabbed the O2 bottle on my boat in the last year, it was due to a situation where he miscomputed his RNT on the tables and thought he had more bottom time available on a repetitive dive than he really did. The consequence, according to the air table (which he was using), was that he had omitted a good 10 minutes of mandatory deco - depending on who's table you were using (PADIs or SSIs) he was over the NDL on that second dive by anywhere from 6 to 15 minutes!!
In truth he was breathing 30% Nitrox on that second dive (but not the first), and when we looked at the profile with a VERY critical eye later, back on shore (from his buddy's computer - and they were nailed to each other during the dive) he was JUST inside the NDL on that second dive under the PADI tables (but still over on the SSI ones), when accounting for the EAD of the 30% Nitrox mix. "Just" meaning that he had ONE minute left (!)
But on the boat, post-dive, when questioned about his profile and SI (it just didn't sound right to a couple of us on board) he went back and re-ran the tables and said "oh $hit", shortly thereafter followed by his personal decision to grab and consume the O2. On the boat we did not have the ability to look critically at the first dive's profile and determine his ACTUAL bottom time (a minute or two makes a difference; all he had was a dive watch with a moveable bezel, which is not accurate to the minute) nor could we be that precise on the SI (again, small increments matter on the PADI tables.)
The computer review later, on shore, said that he was within the NDLs, but just barely.
What PROBABLY kept him from getting hit was a combination of:
1. VERY slow, good, ascents during both dives, along with extended "safety stops" and a very slow final ascent (on the second dive he was diving with me - but not on the first.)
2. Breathing the 30% Nitrox (intentionally, although he was diving it as if it was air) on the second dive likely was the most important factor. If he had been breathing air on that second dive, he would have been grossly in excess of the NDL.
3. Looking at the ACTUAL profiles later, and looking at VPlan later, it also appeared that even on air, using the actual profiles dove (including the deep stop, safety stops, etc) he omitted about 2 minutes at 10', with no conservatism. Not good, but not nearly as bad as it looked on the boat, where a quick "table check" indicated that he had omitted at least 10 minutes of deco!
4. The O2 washout could not have possibly hurt, and may have kept a chamber ride away. The cost of the O2 fill is miniscule, of course, while the price of chamber ride is extreme, even with DAN insurance (in trouble if not in money)
THe irony of this is that if he had been on a charter boat he would have been strongly discouraged from grabbing that O2 for himself, as such is considered an "emergency" and triggers the entire "chain of care" nonsense. Yet the O2, which he self-administered, may well have kept him from taking a hit that he arguably had coming for his mistake.
This is
the reason that I am opposed to the "standard of care" nonsense that comes with operating commercially or even when a person operates under the aegis of "administering" O2 (or anything else.) It is also why I believe that when diving in a non-commercial environment, where O2 is available, divers should make
their own decision on such matters, and
consume on their own, rather than be administered O2.
This avoids the "standard of care" issues, as nobody is administering anything to anyone - a diver is, in that scenario, consuming a breathable gas on their own in completing their decompression on the surface.
Encouraging people to do that when there is doubt as to need is not harmful - the gas is cheap - and may keep you out of the chamber some day.
(If you're uncomfortable with the idea of carrying around DAN-style O2 bottles, then get an O2-clean regulator, clean an AL40 or AL80, fill it with pure O2, and use THAT on the surface! Label it as a deco bottle - then there is no question as to "administering", as its not "medical-style" gear....) I personally like the DAN kit simlpy because it comes in a nice waterproof Pelican case and that keeps all the gear easily at hand, contamination-free, and ready for immediate use.