Poll on the use of Nitrox

[Freedive WI]

I use nitrox on all dives less than 90'. It makes a huge difference down in the islands when doing 5+ dives a day. I acutally have energy at the end of the day to go dancing with my wife- and not pass out in my dinner like I used to when diving air all of the time. 8)

Up here I use it on all the shallow training dives that I do with students. Even if your only in 30' of water, you can get really tired, sub-clinical DCS, from all of those out-of-air ascents that you must practice over and over with each set of students. :-[

For dives btween 90'-130' I have switched to TRIOX. That is a nitrox/helium mix. It allows for shorter deco than just standard nitrox or air at those depths, plus it keeps my head clear when entering a wreck with students in tow. I usually dive a 30/30 or a 28/30 mix for these depths and my bottom times can easily go up to an hour- not including deco.

As far as dedicated cylinders go, it really depends upon your shop that you go to. In southern Wisconsin many shops offer BOTH. They will have large banks of 40% premix that the can be diluted down to whater ever you need. Plus, they will partial pressure mix all of your deco gasses with higher than 40% 02 in them. This way they can keep everybody happy. The recreational user can get the added benifits without lots of extra cash invested and the tech-head can get what ever they want in their own dedicated cylinders.

Plus, many of the shops rent any kind of tank that you want- doubles, stages, deco bottles.

Jon

[tbrown]

Joel, I thought that when you PP your own that regular compressor air was not to be used, that you needed hyperclean. Is this just an overprecaution?

[DRE]

Question: is there anyone with experience on welding equipment on this board, and if so what do you do to "oxygen clean" your equipment?

[JoelW]

As far as I know, everyone in town that is doing PP fills is using hyperclean air in the PP fills and the regular air fills. I think that the stores in town probably all fall into the hyperclean, or whatever the other names are, air category. If you had an O2 clean tank and had it filled at a reputable facility I can't see that there is much of a problem. The concern about tank contamination comes from getting air from any Joe on the side of the road with a compressor.

Of course, just because you have an O2 cleaned tank doesn't mean that an idiot who doesn't know what he is doing won't kill you when doing a fill.

JoelW

[JoelW]

I do a bit of welding but the cover gas I use is Argon so it's not a problem. But then, I am doing wire feed welding not oxy-acetylene.

JoelW

[LKunze]

Yeah, I think everyone that does nitrox fills has hyper pure air but my concern is when I get air fills at places that don't have it. I assume all places that don't fill nitrox probably don't have hyper-pure air then in which case my tank will be contaminated which is why I opt for premix.

[tbrown]

Amen to that! That's the biggest reason I like banked nitrox. I don't know enough about making my own to know if someone is doing it right or wrong, and I don't want to be around in case of the later.

[DRE]

I've got two questions for those of you who still believe in the O2 clean fallacy:
1) did you O2 clean your tanks and regs in a sterile environment?
2) Have your regs and inside of tanks been exposed to regular, outside air (ambient pressure) after cleaning?
3) Do you think regular air is O2 clean?
4) What do you need to start an O2 fire?

[LKunze]

Those are good questions DRE but which shops are actually going to give you partial pressure Nitrox fills in a tank that hasn't been O2 cleaned? It's my understanding that if your tank hasn't been O2 cleaned and doesn't have the O2 clean certified sticker on it shops will NOT fill your tank with nitrox unless it is banked premix 40% or below. ???

[Freedive WI]

Hyper-filtered air is great, but not always needed. Dick Boyd, of Global corp., has stated that 85% of the compressors out there are already clean enough to mix PP nitorx fills. IF the shop has a newer, clean compressor they can probably do it without the added expense of a hyper-filter. They just need to have their air checked- which they should be doing anyhow. I have seen some shops with some really old compressors pump high 02 deco fills on a very regular basis and not blow-up. I wouldn't recommednit, but it does seem to work for them.

02 cleaning tanks and regs won't garuntee that you will never have a problem, if you pump gas into a tank too fast you could make almost anything burn, but is sure does give you peace of mind if your the one filling it.

Jon