Nitrox regs and octos

[Dwhite213]

So I'm probably going to learn all this when I take my nitrox class in a couple of weeks, but I wanted to get a head start. Most regs and octos can take up to 40% o2 right out of the box right? I see that for more that you need to have one cleaned and rebuilt for nitrox. Can you convert a reg/octo for nitrox if not previously approved for it, and then can you still use air?

 

[Islandheart]

Yes to both questions...

 

[Dwhite213]

Simple enough. Thanks

 

[halocline]

The only exception 'might' be (it's not really clear) some titanium regulators. Other than that, no problem with any reg for recreational nitrox, no special cleaning needed, etc.

There are, as usual, a few caveats because you might be on a charter or with a dive op that balks at nitrox use with non-O2 clean equipment. For no reason of course, but then again so much about the world is unexplainable. Sooo....what you might do is make sure your reg is rebuilt using PTFE grease instead of silicone lubricant, and make sure the o-rings are either viton or EPDM. The good news is that these materials are actually better than the alternatives; the o-rings last longer and the grease is considered to be a better quality lubricant.

As to what you will learn in your nitrox class about appropriate gear handling, good luck! The same people teaching the class are the ones that seem to have little consensus on gear protocols. I believe this is basically about money; the manufacturers and shops want to make sure the nitrox market is as accessible as possible so they can sell it, but also they're worried about liability in the exceedingly-rare-but-potentially-deadly case of a O2 related fire, and nobody seems to have established a set of clear, concise, universally-accepted protocols. Of course nobody will tell you that, they'll just think whatever they say is 'the rules.'

 

[lindenbruce]

21% to 40% and back again is no problem. But, as my understanding goes, if you have a set of regs serviced for higher percentages and you use air, I believe it is recommended to have them O2 cleaned again before using mixes richer than 40%. B

 

[Aquabot]

21% to 40% and back again is no problem. But, as my understanding goes, if you have a set of regs serviced for higher percentages and you use air, I believe it is recommended to have them O2 cleaned again before using mixes richer than 40%. B

So as long as you don't exceed 40% they don't need to be 02 cleaned, does this apply to tanks as well? I too am hopefully take the class in the near future.


Sent from my iPhone using Tapatalk 2

 

[elan]

That is not 100% accurate. As long as you are using so called "O2 compatibe/safe etc" air you do not need to clean them again. For example the same air that is used for partial pressure blending is fine.

21% to 40% and back again is no problem. But, as my understanding goes, if you have a set of regs serviced for higher percentages and you use air, I believe it is recommended to have them O2 cleaned again before using mixes richer than 40%. B

 

[mac.calder]

So as long as you don't exceed 40% they don't need to be 02 cleaned, does this apply to tanks as well? I too am hopefully take the class in the near future.


Sent from my iPhone using Tapatalk 2

It will be covered in depth in your nitrox class - but there are essentially 2 ways nitrox is "made" - either a set nitrox mix is delivered down the fill whip (ie the stuff coming out the end is the nitrox mix you are after - this could either be from a pre-mixed bank, from a membrane system or from a low-pressure blending stick) or by partial pressure blending - in PP blending, O2 is decanted directly into the cylinder, then it is topped with air to make the mix you require. So since 100% O2 is passing through the valve on the tank - that means your tank needs to be O2 cleaned. Basically - unless PP blending using O2 (or blending using a banked nitrox mix greater than 40% oxygen), your tank does not need to be clean. If your tank is O2 clean, you also need to make sure that if you get it filled, it is filled with O2 safe air, because if it's not, then your O2 clean tank becomes not O2 clean - which can have disastrous consequences to the poor guy who next tries to blend in your tank..

 

[USdiver1]

Keep in mind that 99% of recreational divers using enriched oxygen (Nitrox) use 32% - 36% Oxygen, and therefore do not exceed the 40% capacity of today's standard issue regulators. Having Oxygen clean equipment is really more of a technical diving feature (e.g. using 100% Oxygen during shallow water decompression stops to accelerate the removal of Nitrogen from one's tissues). As mentioned above, Oxygen clean equipment, and especially cylinders, should be kept separate and clearly marked so as not to inadvertently allow non-Oxygen clean equipment to be filled with pure Oxygen (a potentially explosive situation).

 

[Aquabot]

It will be covered in depth in your nitrox class - but there are essentially 2 ways nitrox is "made" - either a set nitrox mix is delivered down the fill whip (ie the stuff coming out the end is the nitrox mix you are after - this could either be from a pre-mixed bank, from a membrane system or from a low-pressure blending stick) or by partial pressure blending - in PP blending, O2 is decanted directly into the cylinder, then it is topped with air to make the mix you require. So since 100% O2 is passing through the valve on the tank - that means your tank needs to be O2 cleaned. Basically - unless PP blending using O2 (or blending using a banked nitrox mix greater than 40% oxygen), your tank does not need to be clean. If your tank is O2 clean, you also need to make sure that if you get it filled, it is filled with O2 safe air, because if it's not, then your O2 clean tank becomes not O2 clean - which can have disastrous consequences to the poor guy who next tries to blend in your tank..

Thank you for this info, it was a interesting read.


Sent from my iPhone using Tapatalk 2