300 bar din fittings

[JamesW]

Hi I have been given 2 x 10lts which are 232 but have been fitted with 300 bar din fittings are these ok to use with standard 232 din 1st stages.
Thanks

[Graham_Pettett]

Probably yes, virtually all regs have 300 bar capable DIN threads. You can do a visual check, if your reg has 5 or 6 threads (depends how you count them) it is only capable of 232bar use. It it has 7 or 8 threads it will do 300bar. It is deliberately designed this way for safety so you can't attach 232 bar rated kit to a 300 bar source. Also, you will easily tell when you turn the cylinder on if air rushes out from the DIN fitting as if it is 232bar it wont have screwed in far enough to make a seal, hence the safety design.

[PeteM]

Probably yes, virtually all regs have 300 bar capable DIN threads. You can do a visual check, if your reg has 5 or 6 threads (depends how you count them) it is only capable of 232bar use. It it has 7 or 8 threads it will do 300bar. It is deliberately designed this way for safety so you can't attach 232 bar rated kit to a 300 bar source. Also, you will easily tell when you turn the cylinder on if air rushes out from the DIN fitting as if it is 232bar it wont have screwed in far enough to make a seal, hence the safety design.

However make sure the shops knows they are 232's - I've seen shops try to pump cylinders like this to 300bar, not in itself dangerous but not a good idea. Most people mark them up clearly as 232

[Steve Pearson]

Hi I have been given 2 x 10lts which are 232 but have been fitted with 300 bar din fittings are these ok to use with standard 232 din 1st stages.
Thanks

The answer to this one if I understand you correctly is NO!!!

Firstly to address the issue of the 232bar rated cylinders fitted with 300bar din fittings, this could be dangerous from a filling stations point of view. The owner of soveriegn divers in the Farnes had an accident last year as a result of someone giving her a cylinder that was exactly the same as yours. she connected it to the 300bar output which resulted in the valve being blown off and causing quite a bit of damage in the shop. She was only slightly hurt, but it could have been much more serious.

The second issue, will a 232bar 1st stage fit.....No, 232bar 1st stages have 5 threads and 300bar has 7 threads, to prevent the 1st stage engaging in the valve and possibly resulting in serious damage.

My recommendation to you is, remove the pillar valve and replace them with the correct ones. After all when dealing with high pressure gases you are putting lives in danger.

Hope this clarifies things

Steve

[Adrian Kelland]

Firstly to address the issue of the 232bar rated cylinders fitted with 300bar din fittings, this could be dangerous from a filling stations point of view. The owner of soveriegn divers in the Farnes had an accident last year as a result of someone giving her a cylinder that was exactly the same as yours. she connected it to the 300bar output which resulted in the valve being blown off and causing quite a bit of damage in the shop. She was only slightly hurt, but it could have been much more serious. Surely this was as a result of not checking the cylinder Steve. It is quite possible to get 150 A clamp cylinders. I would not expect it to be filled to 207/228/232 just because it had an A clamp. Neither would I expect the pressure rating of any other cylinder to be defined by the valve fitted. If the manufacture side of the industry did not want this to happen, they could use different thread so that 300 bar valves could not be fitted to 232 (or whatever).

Adrian

[Graham_Pettett]

Surely this was as a result of not checking the cylinder Steve. It is quite possible to get 150 A clamp cylinders. I would not expect it to be filled to 207/228/232 just because it had an A clamp. Neither would I expect the pressure rating of any other cylinder to be defined by the valve fitted. If the manufacture side of the industry did not want this to happen, they could use different thread so that 300 bar valves could not be fitted to 232 (or whatever).

Adrian

Furthermore, the failed cylinder must surely have been defective, as a 232 bar WP cylinder would have a test pressure of 348 bar, so the expected failure pressure should be significantly above the test pressure.

[Adrian Kelland]

Furthermore, the failed cylinder must surely have been defective, as a 232 bar WP cylinder would have a test pressure of 348 bar, so the expected failure pressure should be significantly above the test pressure. Indeed - probably on over stretched threads if this cylinder had been filled similarly many times.

All the more reason to read the cylinder - OT2 ;)

Adrian

[iain aitchison]

Dear James,

a typical male fitting DIN reg will be set up for 300 bar and will fit either a 200or 300 Bar female fitting cylinder valve. A 200 bar DIN reg will not seal on the 300 bar cylinder valve. Therein lies the inherent safety of the system.

By fitting the wrong valve, as in your set up, it would be possible to accidentely fill to 300 bar as the connection fittings would seal.

Whether the 300 bar valve fittings are structurally adequately fitted into the cylinder (even maybe for 232 bar) is to be very much to be doubted - they are not designed to be compatible.

The previous owner may also have been regularly overfilling the cylinders into the range 232-300 bar causing pernament damage to them and being a danger to all around them in the process.

By fitting combinations not described as compatible in the DIN together, the owner becomes the legal manufacturer of the combination with all the legal consequences that brings. The legal case is damming as the DIN would specifically forbid the combination.

The 232 DIN system is a misnomer: the relevant DIN recognises 200 or 300 bar for diving cylinders only.

You would be well advised not to use the cylinders at all even after changing the valves.

regards
Iain

[Neil_B]

This thread has sprung a few errors based on assumptions. I speak from personal knowledge as the cylinders involved in the Farnes were mine.
Certain observations are correct; 232 Bar equipment is different and will not seal in a 300Bar pillar valve, which avoids accidents with 232 Bar first stages being blown apart by 300Bar air. However, this safety measure does not work in the dive centre as a 300Bar whip will seat perfectly well in a 232Bar valve, allowing the 232Bar cylinder to be charged to excessive pressures.
My cylinders and their valves are of the 232Bar variety, but were attached to the 300Bar whip by one operator (no names, we just need to learn from this) who may have intended to watch the gauge carefully but then left the shop. The filling was then taken over by the owner, who assumed that the cylinders were 300Bar because they were attached to the 300Bar whip and proceeded to charge the cylinders to well over their 232Bar WP. It is not clear how the whip became detached while still pressurised, but it thrashed around like a wild thing and we can all be grateful that no worse injury was sustained than a small cut on the forehead, and no worse damage than a few lumps knocked out of the wall by the flailing hose. The cylinders and pillar valves survived perfectly well apart from one valve sustaining some damage either through excessive pressure or from falling against the wall. I believe we can be thankful for the routine inspection and test to which our cylinders are subjected, as a faulty or damaged cylinder could have produced far worse consequences.
In conclusion, the only certainty is the markings on the cylinder and any operator should check these before assuming responsibility for the filling. The only certain way to prevent this confusion would, as has already been observed, be to have totally different threads for the different working pressures. DIN fittings, as they stand, are safe for us divers but not for filling station operators.

[Nigel Hewitt]

DIN fittings (http://www.nigelhewitt.co.uk/diving/din.html)

HTH