Need for O2 cleaning and service after 32% Nitrox dives???

[banudemircioglu]

Let's drill down on this.
If you have a modern regulator that has been authorized for Nitrox, it really just means it's been manufactured according to current practice. Virtually ALL current regs are good for Nitrox up to 40% out of the box. The Compressed Gas Association won't commit to acknowledging this, but common practice and lack of liability has made it established fact.

That being the case, you said, "[The dive shop said] I had to service my regulator every time after using Nitrox (not more than 40% O2, I usually use max 32%).
Is it true that I have to service my Aqualung Regulator every time after using Nitrox in order to switch back to normal air dives?"

Your dive shop has things completely backwards, or perhaps you misunderstood what they were saying. At some shops, the air compressor is different (and less rigorously filtered) than the Nitrox system. That gas might contaminate your regs with hydrocarbons that would necessitate an oxygen cleaning if you subsequently wanted to use MORE THAN 40% EAN. Shops don't generally require oxygen clean regs for EAN <= 40%.
So asking you to have your reg "serviced", assuming they mean "oxygen cleaned" to go back to "dirty" air is backwards. And if they truly said "serviced", then they're just scamming you.

So let's assume you misunderstood, and they meant to say you had to have your regs oxygen cleaned if you wanted to go from air to Nitrox.

That may or may not be true. If they "partial pressure blend" their Nitrox, they're adding pure oxygen to a cylinder and then diluting with air. The cylinder needs to be oxygen clean, but once you attach a reg, it doesn't need to be oxygen clean if the final EAN is less than 40%, by common practice (even though the CGA says 23% is the limit).

And if the shop uses a mixing stick and the same compressor system for all their gases, then ALL their gas is oxygen clean, at all concentrations from 21% to 100%.

Perhaps they're concerned that you got your gas elsewhere, and it was contaminated with hydrocarbons. That's YOUR risk, not theirs. If they give you clean gas and your reg is "dirty", you might have some risk with EAN40, though experience says not.

If they're truly telling you that you have to service a reg to go back to air, they're scamming you.

If they're truly telling you that you have to service a reg to go back to Nitrox after air, they're STILL scamming you. Common practice says you're okay to EAN40 without further cleaning, much less a reg "service".

Maybe it's a misunderstanding.

Ask them why...

Wow thank you so much for this it is much clearer now... They said that after Nitrox use there might be a contamination problem because of bad 'oil' accumulation. I'm translating what they said so it might not be completely accurate but this is what I understood. In any case, after many insightful feedbacks I don't think I will service my reg since I only use EAN32...

Also, what do you think about specific Nitrox regulators, are they only for tec dives or how and why are they used in rec dives?

Thank you again for taking the time to answer !

 

[Imla]

Honestly... I don't think you'll find a tech-diver out there using "nitrox regulators". We use normal regulators, and just make sure to clean and lube with proper o2- grease when the need arises.
In my home-area (Norway) scubapro and apeks are quite popular... the go to colour is black...
And while I do believe that Norway should/are? following the m26 valve rule thing I still have not seen anyone using it. And, I have never had an issue bringing my NON-m26 Rebreather O2 bottles in for a fill in France cave-country either. Keep it simple.

The valve/tank needs to stay clean to partial pressure blend O2 on it. To keep the bottle/valve clean, three things need to happen. The reg you connect to it needs to stay clean. The filling whip you connect to it has to stay clean. The gas you fill on it has to be clean.
Needless to say... this is more or less a hopeless task to fulfill... (Pun intended) Your regs might get in contact with hydrocarbons in the bag. In the car. On the boat. The filling whip come in contact with tons of bottles every day. Some belongs to diligent owners. Some don't. The gas might be pure. The filter could malfunction. (Even in the shops with the absolute best of rutines. However, extremely rarely)

What I am trying to say... if you don't have any tanks, and you are not breathing anything over 40%. Then no worries. If you have your own tanks, be mindful of where you fill. Use reputable fillers. If you fill your own o2 tanks, pressurise slowly, and fill slowly.

 

[JMBL]

Diving in living in France, so knowing the damned local regulation about Nitrox, I can confirm your LDS told you a fat load of BS.

Concerning Nitrox ready regulators : buying one in France will imply it's M26 fitted, not at all convenient when travelling like you do, so avoid them like the plague.

I've got one, but only to dive Nitrox above 40% O2 for deco. I got my self an old Aqualung Calypso Nitrox in perfect condition on fleabay, dirt cheap. A very basic regulator, but who needs something better while using for 20m max up to topside ?

Concerning what @Imla told us : having no problem to get is non 26 O2 rebreather bottle filled. It's possible indeed but not everywhere, you have to be sure before getting to the filling station. To avoid that problem my deco tank and my rebreather tank are M26 fitted.

 

[Wibble]

@JMBL - Are there France-specific cylinder testing rules which might affect 'foreigners' coming to France?

 

[JMBL]

@JMBL - Are there France-specific cylinder testing rules which might affect 'foreigners' coming to France?

Yeah I fear.

In France, any tank must be tested every 2 year, unless it is registered to a FFESSM club, and IV at least once a year, and tested every 6 year. You cannot get it filled if you don't comply with these rules.

 

[rsingler]

Well, I just talked with Mark Gresham of PSI-PCI.
I may have to eat crow.
It could be that you have a shop that is really by the book, because Mark says that legally, what you were told is correct by U.S. standards (even if it makes no sense as long as the gas has been oxygen clean at whatever EAN).

According to CGA C-10 (I'm waiting for the actual text now), a visual inspection must be performed any time you switch class of OSHA-defined gas, EVEN IF YOUR SUPPLY HAS BEEN Modified Grade E or better throughout. Class 1 gas is EAN 23.5-EAN100. Class 2 gas is Air, defined as with an oxygen content of from 19.5% to 23.5%.

It makes no sense, but that's the law. And Mark implied that it applies to first stages as well as cylinders, although that may be a pretty expansive interpretation of the CGA standards, which are incorporated by reference into much of the Code of Federal Regulations.

Obviously it was intended to prevent introduction of hydrocarbons into oxygen equipment, but ignores that shops that hyperfilter all their gas aren't going to have hydrocarbon issues just by going back to EAN21 (which Mark points out doesn't legally exist). Once your gas is below 23.5% O2, it's a Class 2 gas, invoking the CGA standard, and the requirement for an inspection exists even going the safe way: from EAN to Air (i.e., clean gas to "dirty"). Like I said, it makes no sense.

Since many shops create their Nitrox by partial pressure blending with pure oxygen, you can see where the problem would arise. But why the standard requires an inspection when going back to Air is bewildering.

The shop could be paranoid about OSHA enforcement actions, or they could be using the law as a profit generator. But legally, it turns out that they're certainly correct when it comes to cylinders, and may be correct when it comes to regs. I'll know more when I see the actual text of the standard.

 

[L13]

...
The shop could be paranoid about OSHA enforcement actions, or they could be using the law as a profit generator.
...

In either case, you want to find a new shop.

 

[Jens Bölte]

Hello,

so you dive regularly in Egypt and get your regulators serviced in France? The US-regulation do not apply in Europe but there might be similar regulations in Europe. I never heard or read of such regulations in Europe. So, it might be nice if your shop gave you the reason for its suggestion to get the regulator serviced when going from Nx32 to air.

Best wishes Jens

 

[Jens Bölte]

Yeah I fear.

In France, any tank must be tested every 2 year, unless it is registered to a FFESSM club, and IV at least once a year, and tested every 6 year. You cannot get it filled if you don't comply with these rules.

How do you checked that there has been an IV? You get a sticker on the tank?

Best wishes Jens

 

[JMBL]

How do you checked that there has been an IV? You get a sticker on the tank?

Best wishes Jens

The sticker was the solution for years. Now evey IVed tank is registered on a national data base, run by the FFESSM and you get a pdf sheet for it. Any filling station can check the data base as well.