CE stamping Carbon Fiber Tanks in Europe

Brainx3

Hi guys,


I got a nice source of carbon fiber hier pressure tanks but the company who makes them does not get them CE certified even though they have been in business for years and that's something I don't understand why exactly. My question is, if I want to buy a couple of tanks and use them within the EU, is it possible to get them tested and certified? I would appreciate some info, links, references, etc. I know the CE issue has been discussed before but I still couldn't find out where and how and if this new materials is accepted to be used within Europe as I couldn't find anyone selling them around.


Best Regards. Wael

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Doorduijn, Niels

Wael,

The situation in Holland with tanks is as follows and I expect this to be more or less the same for Sweden. Scuba tanks, like any consumer product, need to have a CE certification, which is something that the manufacturer or the importer arranges for. Certification is a self-evaluation thing for the manufacturer and I understand that some manufacturers outside the EU do not want to do it for costs reasons (this is usally the case for products with a limit market within the EU, like some type of rebreathers).

You cannot take an item and arrange for CE testing yourself. In practice, all tanks sold in Holland are CE tested, except for a small quantity of DOT certified alu stages which some people import themselves. Whether or not a tank is CE certified (as apposed to only DOT certified) is - as far as I understand it - from a divers point of view mainly relevant when you are teaching or otherwise commercially involved in diving.

In addition, tanks need to be hydrotested from time to time. When you buy a normal tank, it has a hydro-test stamp with a date, which means it needs to be re-tested by then. In Holland, the stamp is normally from a Dutch organisation, I forgot the name. Some imported tanks lack the original Dutch hydro-testing stamp to start with and then the re-testing (usually after 5 years I think) can be tricky, but apparently if you know your way around the system it can be done.

Hope this helps.

Rgs,
Niels Doorduijn

Dutchy

Niels,

It's perfectly fine to use a non CE tank and in fact you can have some of them hydro tested and re-stamped perfectly fine. I wrote a response some time ago that detailed what to do with some of the DOT tested tanks.
There's nothing difficult about it and it doesn't have to be epensive especially when it is a 'known' tank. It's just that some shops would much rather sell you new tanks than go the extra mile.
I'll add a link to the previous post it is in Dutch but I provided a translation (for everyone but him)...http://www.rebreatherworld.com/rebre...tml#post171765

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Brainx3

Hi,


Thanks guys for the reply. So in other words, if the tank was never been tested in Europe then in theory it can be tested and stamped then used as other tanks? I also wonder if the pressure test method used is the same for all types of tanks? Anyone has any idea about the new carbon fiber tanks?


Best Regards. Wael

__________________
The depth of life cannot be measured in Bars, nor can the sea of lies, that lies within.

I don't take crap for an answer...

AD_ward9

We have been trying to get CE carbon SCUBA tanks for quite a while. There a few things to look out for:

1. The tanks with a plastic liner are not O2 compatible, at all.
2. The tanks with an aluminium liner corrode severely in sea water, very fast: the aluminium is not protected.
3. They normally have 18mm tank threads.

Very few companies make pillar valves to fit 18mm that are any good for SCUBA applications, and those that do make poor quality valves (we tried 3 manufacturers' valves, all leaked within a week, and two were obviously not O2 compatible). Just now we are doing an NRE contract with Poseidon: they make very good quality valves, the NRE bit is to get them with an 18mm thread - you would be astonished at how expensive such a simple change is, on what is already an expensive valve. One has to do it twice because the new G5/8 and 26mm Nitrox regulations in Europe.

We tried to overcome the corrosion problem by doing an NRE contract with a major US tank manufacturer, to put a diamond like carbon coating on the liner before wrapping it with carbon. The first 12 of these 300 bar O2 certified tanks arrived yesterday: diamond like carbon everywhere except the threads and top of the neck, where we need it. We explained in writing that we had to have the coating on the threads, but some manufacturers are better at reading email and letters than others. That was expensive!

We will try again ... if they still speak to us after getting a snottogram advising them of the utility of what we received.

So unless you have deep pockets and even deeper patience, my advice is to just use aluminium cylinders.

Once you have got cylinders that work, they need to be properly tested and certified. One of the little problems with certification is the tanks need marking. You cannot use a punch with a carbon cylinder to mark test dates, so you have to add a ring to the neck with this information.

Alex

Tino de Rijk

Uhm..... at least 7, 10 and 12 liter carbonfiber tanks (as in: thinner steel or alu tanks with carbon wrapping around it for inforcement; If memory serves me well from austrian's Worthington), with normal M25x2 neck thread, have been available on the Dutch market for quite a while now, WITH CE rating, so I don't understand the problem really.....

This is a quote from a Worthington brochure on what they call "composite" cylinders:
" A composite cylinder consists of two or more physically distinct and different materials that are combined to achieve a product having superior properties than the original materials alone. Composite cylinders typically are a steel or aluminium liner cylinder wrapped with carbon fibre, thus allowing it to withstand higher pressures at a reduced weight.

If I read Alex' reply well, maybe he is talking about all-carbon cylinders (so no steel inside)...? Because the ones I saw (and my mates use, and I have currently on order to replace my 7 liter alu sidemounts) do have normal stampings in the (non-wrapped) thicker steel/alu neck part.

Problem is there are also other types of carbon tanks (e.g. Drager) that were made for non-diving purposes (e.f. for fire brigade) and as such very rightfully so will not get a CE-rating as a diving cilinder. The wrapping used on those is not water-resistant, to put it overly simplistic.

ciao,

Tino.

Tino de Rijk

Hmm..... did you actually try it yourself? The nasty word here is "known".
I tried to get my 3 liter Faber cilinders from my Inspo tested a few years ago, before they carried the CE marking (now it shouldn't be a problem anymore, carrying CE).
It involved quite a lot:
- getting APD to send me the production papers from Faber on production method, actual batch wall thickness, etc. (as usual they were very forthcoming);
- going to Lloyds in Rotterdam, present it all in a formal request, with pictures of cylinders and stampings;
- paying quite some money (don't know exactly anymore);
- having my cylinders downgraded from 232 bar to 200 bar, as the wall thickness was deemed just too thin (see if I care....!);
- finally getting a formal paper with which you need to go to the actual pressure testing house to get them do the testing (re)stamping.

Cynically enough, my oxygen cylinder returned with "oxygen" stamped on it (o.k.) - and a 10 (TEN) year approval, which is normal for -industrial- oxygen cylinders... Needless to say I ignored that, and had them retested as per normal in Holland, after 5 years (the 10 year has now been abandonded also for "consumer" cylinders).

In the end I succeeded, but it took quite some trouble. And Faber is a European (Italian?) manufacturer.

so getting it labeled "known" for a non-CE rated cylinder is not that easy.... (although doable). Others after me could benefit from my action at the time.

Ciao,

Tino.

Brainx3

Hi,


Tino, I really thank you for the information you provided as that was very useful. I have tried to search online for the Carbon Fiber cylinders that you referred to "Worthington Cylinders" but they didn't specify anything on their website the carbon fiber materials they are making for diving purposes. I would appreciate some links and/or a reseller's link to where they are sold and some more information about their products of such kind.


Best Regards. Wael

__________________
The depth of life cannot be measured in Bars, nor can the sea of lies, that lies within.

I don't take crap for an answer...

Dutchy

I think that is the key factor here. You went through the trouble yourself. Now it is 'known'

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AD_ward9

The cylinders we bought had aluminium liners, wound with carbon, manufactured by SCI (Harco). Hence the corrosion problem: the same as for the Worthington cylinders. Without protection, we wrote the cylinders off in a week of diving.

The Worthington cylinders are not CE rated for SCUBA use, at least last time I checked they were not (about 9 months ago). As military cylinders, they do not have to be CE rated: they are exempt. They are DOT rated, and marked for 300 bar, just like the SCI cylinders. The SCI cylinders are rated for 300 bar of O2, rather than air. Both have the problem of an unprotected aluminium liner, which is very much thinner than for a normal aluminium tank so tiny amounts of corrosion are terminal.

The large 5+ litre Worthington cylinders are indeed 25mm thread, but the small ones for rebreathers (e.g. 2 litre cylinders), are 18mm thread, just like SCI's.

If there is a source of reliable light small diving cylinders that can get through CE testing as is, I would be very interested and would buy a pallet load tomorrow.

Cheers

Alex