Help cut Gordian knot - regulators & their technologies, Nitrox and cold water

[DevonDiver]

So what do I do?
I cannot (safely, legally and mechanically) put Nitrox into a cylinder for compressed air, so I definitely need a cylinder for Nitrox.
But then the normal regulators (not explicitly certified for Nitrox or up to 100% oxygen - but maybe officially usable up to EAN 40?) will not fit my cylinder?!?!
How is this solved?!?!

I'm not sure... I left Europe just before the introduction of this ludicrous policy.

To make things worse, the rest of the world doesn't use these fittings - so you won't be able to use your regs with rental cylinders if you go outside of Europe on holiday...

I have seen in another thread that all regulators from Oceanic (document is from December 2008) have a "Nitrox compatibility" of "Standard to 40%".
Can I safely assume this to be true for regulators from other manufacturers as well?

Be aware that some manufacturers do market certain regulators as 'nitrox compatible'... but this is quite spurious, because (other than the valve issue in Europe) there aren't any specific requirements for nitrox use below 40%. Basically, they are charging you for using oxygen compatible components that you don't need for recreational nitrox use.

It also says there that this regulator must be serviced by a certified technician after using it with pressurized air instead of Nitrox.
Why that? Isn't pressurized air just the same as Nitrox with 21% oxygen?

Again... for use with recreational nitrox, this is not a requirement. Only regulators used with >40% oxygen require special cleaning or components.

Basically... if you are using recreational nitrox (<40%) neither your regulator or BCD requires any special cleaning, servicing or components. The only thing that might is your cylinder... and that is only if you have it filled via Partial Pressure blending (because it is first filled with pure O2, then topped up with air).

 

[cosmos]

Hi LarsB,

maybe i can answer some of your questions. but my english is not so good.

in europe you have indeed some special regulations about nitrox and nitrox is all above 21% o2 and that goes up to 100%. that means you need special regulators and equipment which muss be o2-fit and o2-clean.

21% or 40% isn't a great deal and i think the 40%-limit comes from noaa. imho cga says also above 21% must be o2-clean.
but i'm not shure.
what it makes a little bit complicated is that for safety reasons there is another regulator connection (M26x2). the reason is that you can't interchange nitrox with air by accident. so you need some other tank-valve for your nitrox regulator.
and yes, now you have the next problem. at time even in europe this connection isn't common. so when you travel there no bottle for your
regulator.
This all is a little bit complicated and i think the people which comes up with this safety improvement wasn't realy clever.

practical most divers in europe dive nitrox with standart din fittings. they makes their equipment o2-fit and o2-clean like the rest of the world and that was it.

i think the poseidon bcds are nitrox certificated.

cheers christian

 

[LarsB]

Thank you all so much for your answers!

I indeed only intend to use recreational Nitrox <40% O2.

I conclude that the best thing for me to do is to go and see my local dealer and ask him a LOT of questions, in order to make sure I buy the equipment most compatible worldwide...

Since the EN 144-3 fittings are uncommon on a global scale, I need a regulator with "conventional" fittings, e.g. 300 bar DIN or 232 bar INT (yoke).

The question is how do I get an O2-clean cylinder (for partial pressure blending, otherwise I might not be able to fill at some filling stations) with fittings that this regulator fits on...

 

[LarsB]

Dear all,

I just came back from the shop and after posing them a lot of questions things became much clearer.

I came to the conclusion that in order to be usable worldwide, a regulator with DIN fitting and an INT (yoke) adapter is my best choice.

In fact, I just bought the Aqualung Legend LX Supreme ACD with Aqualung Legend Octopus and Suunto console (manometer and depth gauge).

I hope I will never regret this buy and that it will serve me well and long.

BTW, I liked the features of the ACD system and the lip protector.
We'll see how they fare in practice...

With respect to the cylinder, there is only one shop here in the region (for tek diving) which offers partial pressure blending, all other shops use membranes.
An O2-clean cylinder would therefore be overkill. A normal cylinder will do.
This also nicely solves the problem of the incompatible fittings.

Cheers,
LarsB

 

[Hallmac]

for the Aqualung line:
Legend, legend lx, legend glacia = Over balanced Diaphragm 1st stage, balanced 2nd stage, EAN40 out of box. has ACD option
Titan = Balanced Diaphragm 1st stage, unbalanced 2nd stage, EAN40 out of box,
Titan LX =Balanced Diaphragm 1st stage, balanced 2nd stage, EAN40 out of box, has ACD option
Titan LX Supreme = Over balanced 1st stage, balanced 2nd stage, EAN 40 out of box, has ACD option
MiKron = Balanced diaphragm 1st stage, balanced 2nd stage, EAN 4 out of box,
Calypso = Unbalanced, in-line piston 1st stage, unbalanced 2nd stage, EAN 40 out of box
Kronos= balanced diaphragm 1st stage, balanced second stage, back flow exhaust to warm incoming air, ACD, EAN40 out of box.
Kronos Supreme = Over balanced diaphragm 1st stage, second is identical to above.

 

[CPH]

I live just over the boarder in Holland and I have seven sets of mk25 with A700, GV250's, R395's, S555's.
Never had to worry about the new threads yet. Everyone still uses the old threads.
The Apeks or Scubapro's will serve you very well. I hear people all the time complain about Scubapro's free flowing. 99.9999% of the time it is not a free flow, it is a second stage with air in it when they enter the water for the first time. I, and the missus both dive in VERY cold waters and under ice and never had a free flow yet.

 

[Capt.Gene]

Environmentally sealed PISTON regulators often have the spring chamber filled with grease. Grease passes on the ambient pressure just like water but won't freeze hard at the same temp.
Diaphram regulators (you call membrane)by defination, exclude all water inward of the diaphram, and grease is only used as a lube on moving , or dynamic, O rings..
The external spring chamber on a diaphram regulator can freeze and ice can stop the spring from compressing.The sealing diaphram above the spring chamber is designed to prevent this and the accidental air space inside the now sealed off spring chamber becomes the "Overbalanced" gimick you mention when at depth the air volume compresses and pushes a "pressure transmitter" against the spring pad.

 

[DuboisP]

It's not just CE compliance... European regulations now demand a specific DIN connection (M26) for nitrox use. It uses a different thread diameter and cannot be used with air compressors or regulators.

As you might guess... it's a much loathed policy.

not true
it's only in France, and it's mandatory only for new equipment.
but LDS don't know the regulations and sometimes don't want to fill your "old" tank, even it is cleaner than their compressor.

 

[DevonDiver]

Things must have changed since I left Europe then... because there was lots of consternation in the UK about the pending introduction of the M26 thread there. Did it not go ahead?