Old Steel 72 Numbers ?

[JohnAC]

Today I picked up an old steel 72 for beach diving at the LDS. The numbers on the tank read as follows.

ICC-3AA 2250 XG

HJ 171356.........................................7 c2 95
.........................................................82
9 68+ ..............................................3 02 02
.........................................................82
5 73 ................................................1 D2 07
..........................................................82
5 73

10 89
77

I understand the IIC-3AA is pre DOT, and 2250 is working pressure, HJ were tanks made by PST. Just curious about the other stuff?

 

[Gombessa]

I'm no expert, but ...

+10% is 2475, so it's at 72CF at 2475psi, 68cf at its current rated pressure of 2250.

Seems like the original hydro date (with plus rating) was in September 1968. Hydro'd again in May 1973. Then in July 1995. Then in march 2002. Then again in January 2007. Could have been hydro'd sometime in 1989 (month indicator is missing - should be a big number in front of the last 10/77).

 

[DA Aquamaster]

ICC stood for Interstate Commerce Commission before it became the DOT (dept of Transportation)in 1967 or 68.

3AA designates an engineering standard for steel tanks, meaning they are cetrified under that standard and not a special permit.

2250 is the service pressure. With a "+" rating and the allowed 10% overfill to 2475 psi, a generic steel 72 held 71.2 cu ft. At 2250 psi it is 65.1 cu ft.

HJ 171356 is the serial number. 9 X 68+ is the oroiginal certification date and the whatever is in place of the "X" is the stamp of the manufacturer that certified the tank.

If memory serves, PST made tanks in an HJ series for Healthways.

The other numbers will be test dates in a month and two digit year format with a code for the test facility in the middle. That usually consists of a letter and 3 numbers arraned in a sqaure.
For example:

C2
00

 

[JohnAC]

Thanks for the info, this tank has an old Scubapro k valve that i'm thinking of up grading. Any brand recommendations?

 

[captain]

Unless you want to change to a DIN valve I see nothing you will gain by changing the valve. Either it leaks or it doesn't, there really nothing to else that can happen. You should change the tank to valve O ring.

 

[JohnAC]

Will do Captain, thanks for your advice! Hopefully I will be doing a beach dive w/new-old tank at Refugio state beaches east side reef on friday.

 

[phrog]

I'm new here, so I have what you may think is a silly question.. I too have just recently picked up an old steel 72 tank that has similiar markings to what is listed above (ICC3AA2250) - does this mean that my tank can only be filled to 2250PSI? I could've sworn that the guy I picked it up from had it listed as a 3000PSI tank? Can somebody clear this up for me please?

 

[herman]

I'm new here, so I have what you may think is a silly question.. I too have just recently picked up an old steel 72 tank that has similiar markings to what is listed above (ICC3AA2250) - does this mean that my tank can only be filled to 2250PSI? I could've sworn that the guy I picked it up from had it listed as a 3000PSI tank? Can somebody clear this up for me please?

Yep,you pretty much have it. 3000 is not likely to explode it but it's a really bad idea. There is nothing wrong with using a 2250 tank....

 

[phrog]

Thanks for the quick reply.. that being said, this is an older tank.. and it was accidentially over filled (greater than the +10% stated on it) and now the burst disk has a leak.. this is an older healthways tank from the 60's - anybody know where I can get replacement parts for this tank and valve? I've removed the burst disk and found that there a small copper looking disk behind the burst disk screw that has a hole in it - anybody know anything about this older style burst disk? it appears to be serviceable - instead of simply replacing it like the newer types.

 

[Luis H]

Any good dive shop should be able to help you with a replacement burst disc. Some dive shops may not have the properly rated disc in stock, but they can order it.

Once removed you don’t want to reinstall the old burst disc…it can let go at a lower pressure since the thin metal disc will now have two different cutting lines.

The disc and the screw should be replaced as a matched pair. In the old days we used to only replace the disc, but since the screw is the cutter for the burst disc you don’t get a consistent relief pressure if you don’t replace it as a matched pair.

Also the old screws that only had one hole in the center are not used any longer. The new ones have a hex head with three holes to balance the air steam force so the tank doesn’t start spinning around if the burst disc lets go.

The cost of replacing the burst disc assembly is not much.

Make sure they torque it properly or again it will be unreliable.

When the tank is re-hydro they can add the “+” again. Even with out it many LDS will fill them the designed pressure of 2475 psi (2250 + 10%).

Good luck