Certification Needed For pure O2????

[Lorenzoid]

What cert would I need to carry a O2 pony bottle and more importantly Be able to get it filled? I read where some divers breath O2 at the safety stops and they swear by it. And no not just deco divers mentioned this. although deco diving is something I want more info on.

I'm curious as to what purpose you see in it. Is it because you heard divers mention that it makes them feel better? Or is the idea that it might provide extra protection against DCS? If the idea is that it might help you feel better--less tired, for example--then consider experimenting with breathing O2 on the surface. I have heard of people doing that. Lugging along an O2 bottle on a dive for no reason than to use on a safety stop with the idea that it might make you feel better seems like a lot of work to me. Granted, it should be more effective at 20 feet than on the surface, but weighing the annoyance versus the benefit, I know which way I would go. If the idea is to add extra protection against DCS, it seems to me that lugging along an O2 bottle to guard against you taking that one-in-10000-dives "undeserved" hit is likewise not worth it. But maybe you actually like the idea of carrying a bottle. Me, I aim to carry nothing that I don't need.

 

[kafkaland]

I'm curious as to what purpose you see in it. Is it because you heard divers mention that it makes them feel better? Or is the idea that it might provide extra protection against DCS? If the idea is that it might help you feel better--less tired, for example--then consider experimenting with breathing O2 on the surface. I have heard of people doing that. Lugging along an O2 bottle on a dive for no reason than to use on a safety stop with the idea that it might make you feel better seems like a lot of work to me. Granted, it should be more effective at 20 feet than on the surface, but weighing the annoyance versus the benefit, I know which way I would go. If the idea is to add extra protection against DCS, it seems to me that lugging along an O2 bottle to guard against you taking that one-in-10000-dives "undeserved" hit is likewise not worth it. But maybe you actually like the idea of carrying a bottle. Me, I aim to carry nothing that I don't need.

I would think that the increase in risk from accidentally breathing the O2 below its MOD is larger than the reduction in risk of an undeserved DCS hit that you'd get from breathing O2 at your safety stop. So from a risk management perspective, taking an O2 bottle on dive within recreational limits where you don't need it for accelerated deco doesn't make much sense.

 

[boulderjohn]

I would think that the increase in risk from accidentally breathing the O2 below its MOD is larger than the reduction in risk of an undeserved DCS hit that you'd get from breathing O2 at your safety stop. So from a risk management perspective, taking an O2 bottle on dive within recreational limits where you don't need it for accelerated deco doesn't make much sense.

I agree. I believe the overall DCS rate is about 0.002%. You have to figure that those few cases include people who were not following standard dive procedures or who may have a physiological problem like a PFO. The odds are therefore already very much in your favor by just following standard dive procedures and not having a PFO. If that is not good enough for you, then you can extend the stop to 5 minutes to get some extra benefit. It's a lot cheaper and easier than carrying around an O2 bottle.

 

[kr2y5]

To be fair, this seems a little bit of a blanket statement... some people dive with super aggressive settings and push their NDL... others stay well within NDL. Does the DCS rate apply to the former group? Perhaps in those cases, doing extra O2 has some merit. I am not advocating it, anyhow... I personally would rather set my computer (or cut tables) with a very conservative setting, and do O2 as calculated, as opposed to padding it with a few minutes just in case... but the latter does not seem completely unjustified and unreasonable. (Of course, I'm not defending the approach end-to-end... cutting tables with aggressive parameters just so they are nominally NDL, is deco diving in disguise, and one would be well advised to treat it as deco diving rather than pretending it's not, and do it properly...)

 

[Basking Ridge Diver]

The only other usage that I can imagine for 100% is IWR. Which is a bit on the hairy side and should be avoided if you are headed that way.

Why not just use 50% O2? Much safer and about the same benefit (a few minutes difference depending on your profile) if you are using it for deco.

 

[Lorenzoid]

Why not just use 50% O2? Much safer and about the same benefit (a few minutes difference depending on your profile) if you are using it for deco.

As I understand it, 40% and up requires the same certification, so it wouldn't matter as far as the OP's question of what cert is needed.

And if 50%, then why not 36%? Or less. Or, to take this full circle, just keep breathing your back gas and spend a few more minutes at the safety stop.

 

[Mscdex]

I like the idea mentioned earlier about breathing O2 on the surface after the actual dive. For that, I think you can get a DAN bottle and fill it with an O2 Provider cert

 

[The Chairman]

To be fair, this seems a little bit of a blanket statement... some people dive with super aggressive settings and push their NDL...

The NDLs don't cover every contingency. Fatigue, lack of hydration, age and more all add to a person's predilection to sustaining a DCS hit. I'll gladly carry oxygen if I am going to go into deco, or if I suspect that I could. If it's the latter, then you can be sure that I will be doing my safety stop on O2 if it's there.

 

[kr2y5]

The NDLs don't cover every contingency.

I wasn't suggesting otherwise... I was just saying that DCS rate for people who push the NDLs with aggressive settings could be higher than the one cited.

 

[Jim Lapenta]

I have a friend who took a hit a couple years ago on a dive way within rec limits. Ever since he carries an O2 bottle on every dive and goes to it at the 15 ft stop. As for the cert while Adv Nitrox really should be done in conjunction with deco procedures it is not required it be. The cautions are covered in the course (at least in the TDI class I teach) and the content of it would certainly allow for one to use it as my friend does. It is not a technical decompression dive with mandatory deco. Rather a choice to switch to it within recreational limits. It may also be more convenient in some cases to go on O2 in the water rather than waiting until you get out.

Lastly in some areas you can't get an O2 fill without it. In Ohio it's actually easier to get a deco bottle filled than a surface O2 bottle. One of the things that is covered in the SEI DRAM rescue course is O2 provider. Some rescue courses don't cover that. If you don't have an O2 provider card or if the Rescue course is not recognized as having a valid O2 provider component you need a doctors script to get an O2 fill in your DAN bottle. The Ohio Council of Skin and Scuba Diving has been working with some legislators for years to get this changed.