Scubapro DIN conversion kits: 200 vs 300

[Angelo Farina]

OK I worded that poorly. It's a 3500psi tank that has a 300 bar valve as the 200 bar valve would be insufficient.

Why the 200bar valve would be insufficient? 200bar and 300bar are commercial names, both valves are rated for operational pressures up to 300 bars. And most 232-bars cylinders I have seen are equipped with DIN200 valves, which can also mount yoke regulators, thanks to the insert.
Only a 300-bar cylinder should mount a DIN300 valve, for preventing the risk that one mounts on them a regulator like my old ones (SP Mark5), which are not designed for operating with such an high pressure.
So I think that replacing the yoke, and installing a 200bar DIN adaptor on my regs is fine, as in any case I cannot use them with a true 300 bar bottle, and a 232 bar cylinder usually has a 200bar valve (but not in your case).

 

[JackD342]

Why the 200bar valve would be insufficient? 200bar and 300bar are commercial names, both valves are rated for operational pressures up to 300 bars. And most 232-bars cylinders I have seen are equipped with DIN200 valves, which can also mount yoke regulators, thanks to the insert.
Only a 300-bar cylinder should mount a DIN300 valve, for preventing the risk that one mounts on them a regulator like my old ones (SP Mark5), which are not designed for operating with such an high pressure.
So I think that replacing the yoke, and installing a 200bar DIN adaptor on my regs is fine, as in any case I cannot use them with a true 300 bar bottle, and a 232 bar cylinder usually has a 200bar valve (but not in your case).

At the risk of repeating myself... because in the US the current DOT requirements prohibit the use of yoke regulators on pressures of 3500 psi and higher. Thus any cylinder rated for that pressure or higher has a different neck thread, requiring the use of a DIN 300 bar valve. A DIN 200/232 bar valve will NOT fit that cylinder - it is not a matter of choice.

 

[Angelo Farina]

At the risk of repeating myself... because in the US the current DOT requirements prohibit the use of yoke regulators on pressures of 3500 psi and higher. Thus any cylinder rated for that pressure or higher has a different neck thread, requiring the use of a DIN 300 bar valve. A DIN 200/232 bar valve will NOT fit that cylinder - it is not a matter of choice.

Ah, OK; this is the missing information! So normal 3500 PSI cylinders which here in Europe and in Asia are usually fitted with dual-purpose yoke-Din200 valves are not allowed in the USA, you need to use a DIN300 valve on them....
I suppose this is to prevent the usage of yoke, as the so-called "200bar DIN" valve is actually rated ad 300 bar, when used in DIN mode (according to DIN standard, which of course has no value in the US).
Sorry, but from this side of the Atlantic ocean is difficult to get this kind of technical info. And the usage of different measurement units makes the things even more complex...

 

[Storker]

most 232-bars cylinders I have seen are equipped with DIN200 valves

Because a "200 bar" valve is approved for 232 bar.

I might possibly have mentioned this before.

 

[Bob DBF]

I may perhaps have mentioned this once (or twice, or thrice) before, but it isn't 200 bar. Its 200/232 bar. That's a >30% difference.

In the US the 200 bar DIN fitting is used for 200/232/241 bar, any pressure less than 3500# service. 3500# service pressure, or greater, has to use the 300 bar fitting, although not the pressure. As I said before, the common name of 200 bar is used because that's the initial name in the states, and the US denotes service pressure in psi not bar, so in the US 200 bar DIN denotes the fitting, not the pressure.


Bob

 

[Zef]

The Scubapro universal DIN kit (code 10.045.020) arrived yesterday, today I mounted it on my SP Mark15, and it works perfectly.
I can confirm that, despite being the 200bar version, it fits perfectly all the valves I can see here in our shops.
So I confirm that the 300 bar version is substantially useless, as it is impossible to find cylinders equipped with Din300 valves.

I don't know about Italy but here in Belgium I see folks with 300 bar DIN valves all the time...I am in a local club with some young divers that dive smaller doubles because they can't handle the weight of full size tanks but with twin 300 bar 8 liter tanks they have roughly the same amount of air as 200 bar twin 200 liter tanks.

A 300 bar valve is deeper than a 200 bar valve and while the threaded insert will screw in it will go in too far and yolk 1st stage will not be able to make a proper seal..if the insert is not screwed in all the way the back of the insert will not seal to the back of the valve...this prevents one from attaching a 200/232 bar 1st stage on the HP tank/valve and causing damage to the 1st stage.

-Z

 

[runsongas]

300 bar 8 liter doesn't hold quite as much as 200 bar 12 liter because of gas compressibility issues though.

 

[Luis H]

At the risk of repeating myself... because in the US the current DOT requirements prohibit the use of yoke regulators on pressures of 3500 psi and higher. Thus any cylinder rated for that pressure or higher has a different neck thread, requiring the use of a DIN 300 bar valve. A DIN 200/232 bar valve will NOT fit that cylinder - it is not a matter of choice.

Can you provide a CFR (Code of Federal Regulations) that will talk about this? I have looked and I cannot find anything.

In general it is the CGA (Compress Gas Association) that writes all the codes about the valves, but they are not a regulatory agency. They are a industry association. The CFR in some cases do invoke the CGA documents which in turn it makes them legally binding, but I have not found any CFR document that actually talks about valve fittings.

The CGA does have some different valve-regulator fitting standards for different air pressures (like the ones used on SCBA, but I have never seen requirements for the cylinder neck size. And again, the CGA is not a regulatory agency.

Again if you know of any actual document numbers (CFR or CGA), I would really appreciate it.

From what I can tell the 7/8” threads for higher pressure cylinders was a passing fad and hopefully it will go away and never return.



BTW, this statement down here is not really accurate.

At least in the US, you cannot use a 300 bar DIN valve on a 200/230 bar cylinder - the cylinder neck threads are different.

It is not hard to find 300 BAR DIN valves with 3/4”-14 NPS neck threads.

Here is just one example:

Thermo 300 Bar Din Valve -3/4

2601C - Thermo 300 Bar Din Valve -3/4" x 14 Thread

• Dedicated 300 bar DIN outlet
• Attachment of DIN first stages only
• 3/4”-14 NPSM standard inlet threads
• Air service only
• 3000 PSI Service Pressure

There are also several older cylinders that are still perfectly acceptable (and very legal) that are higher pressure (4400 PSI) that use the 3/4” -14 NPS valve standards.

An example are the Heiser 190. They are stamped DOT-3AA- 4400. Those are not even special permit cylinders, they are just plain 3AA standard cylinders made under CFR49, paragraph 178.37 (Specification 3AA and 3AAX seamless steel cylinders).


I should also add, the document from Dive Gear Express is a great resource (that seem to grow every time I read it) and for the most part it is accurate (some of it is quoting some good back-up documents), but not all of it. From what I recall, some of the write-up have a few assumptions that are not accurate, but they are minor.
SCUBA Valves | Dive Gear Express®

 

[JackD342]

Can you provide a CFR (Code of Federal Regulations) that will talk about this? I have looked and I cannot find anything.

In general it is the CGA (Compress Gas Association) that writes all the codes about the valves, but they are not a regulatory agency. They are a industry association. The CFR in some cases do invoke the CGA documents which in turn it makes them legally binding, but I have not found any CFR document that actually talks about valve fittings.

The CGA does have some different valve-regulator fitting standards for different air pressures (like the ones used on SCBA, but I have never seen requirements for the cylinder neck size. And again, the CGA is not a regulatory agency.

Again if you know of any actual document numbers (CFR or CGA), I would really appreciate it.

From what I can tell the 7/8” threads for higher pressure cylinders was a passing fad and hopefully it will go away and never return.



BTW, this statement down here is not really accurate.



It is not hard to find 300 BAR DIN valves with 3/4”-14 NPS neck threads.

Here is just one example:

Thermo 300 Bar Din Valve -3/4

2601C - Thermo 300 Bar Din Valve -3/4" x 14 Thread

• Dedicated 300 bar DIN outlet
• Attachment of DIN first stages only
• 3/4”-14 NPSM standard inlet threads
• Air service only
• 3000 PSI Service Pressure

There are also several older cylinders that are still perfectly acceptable (and very legal) that are higher pressure (4400 PSI) that use the 3/4” -14 NPS valve standards.

An example are the Heiser 190. They are stamped DOT-3AA- 4400. Those are not even special permit cylinders, they are just plain 3AA standard cylinders made under CFR49, paragraph 178.37 (Specification 3AA and 3AAX seamless steel cylinders).


I should also add, the document from Dive Gear Express is a great resource (that seem to grow every time I read it) and for the most part it is accurate (some of it is quoting some good back-up documents), but not all of it. From what I recall, some of the write-up have a few assumptions that are not accurate, but they are minor.
SCUBA Valves | Dive Gear Express®

Sorry, I don’t have a reference source for you. I based my comments on recent conversations with XS Scuba regarding Thermo valves. I believe that <3500 psi limitation on yoke pressure is not long standing, but more recent. (Maybe 10 or so years, give or take 5?). So no surprise there are some older higher pressure 3/4” thread tanks out there. And yes, I know you can get 300 bar valves for the common 3/4” neck thread, what you can’t find in production today is any valve that allows you to put a yoke on a 7/8” neck thread, which usually are the old 3500 psi tanks.
For a new valve in those, you need this:
XS Scuba 7/8-14 UNF DIN Valve — XS Scuba

I don’t see any current Faber cylinders listed for 3500 or higher in the US, so no current 7/8” threads there.
The one current/recent cylinder in the US that I am aware of with a higher service pressure does use a 7/8” valve, and so is still consistent with the forced use of DIN and not yoke.
Luxfer Limited 106 Composite Cylinder — XS Scuba

 

[Storker]

300 bar 8 liter doesn't hold quite as much as 200 bar 12 liter because of gas compressibility issues though.

My 10x300s hold pretty exactly as much gas as the 12x232s I see all the time around here. 10*300=3000 and 12*232=2784, but rule of thumb is that a 300 bar tank holds about 10% less gas than nominal capacity.

twin 300 bar 8 liter tanks

Can't say I've ever seen a D8x300 set. D7x300 and D8.5x232, though, are rather popular around here.