Steel tank help needed

[DawsonDownUnder]

Hi team

I'm relatively new to the sport and have just picked up a tank and need some help identifying it.

The guy I bought it off said it was a 12.2L.tank but I'm not so sure.

The photo is of all the markings on the top.

The tank is tagged so still in service. More interested in understanding the capacity.

 

[-JD-]

Not a ton of info, dimensions would be helpful.

Looks like a US spec tank "DOT 3AA"
2250 PSI base working pressure. +10% if current hydro is plus rated (at least here in the US) for 2475psi
Original hydro date is 09-1972 and was plus rated from the factory at that time.

If WC on your paper is the measured water capacity expressed in weight, then it would seem to be a 12L. 12L of water is just over 26lbs. https://www.thecalculatorsite.com/conversions/common/water-weight.php

2475psi = 170.6bar
12L * 170.6 = 2047L = 72.4.cuft

And I'm assuming TW is tare weight with the valve?

Maybe an old LP72?

From: Steel LP72 2250psi tank spec

Is this what you're looking for?

72 cu ft Standard
Service pressure: 2250 psi
Working pressure: 2475 psi (2250 psi +10%)
Actual air capacity: 71.2 ft3 (at a working pressure of 2475 psi)
Outer diameter: 6.9 in
Length without valve: 25.1 in
Empty weight: 26 lbs (w/o valve)
Buoyancy Empty: 0 lbs (w/valve)
Buoyancy Full: -5.4 lbs (w/valve)

Capacity at:
2500 71.9
2600 74.7
2700 77.6
2800 80.5
2900 83.4
3000 86.3

and

from: Specs on the old 72cf steel tanks?

This data came from one of my US divers 1970's maintenance and repair manuals:

72 cu ft Standard

Service pressure, psi : 2250
Actual air capacity, ft3 (at 2475 psi): 71.55
Outer diameter, in: 6.81
Length without valve, in: 25.12
Empty weight, lbs (w/o valve): 26
Buoyancy Empty, lbs (w/valve): 0
Buoyancy Full, lbs (w/valve): -5.4

They are not all the same. As mentioned above, there were at least two manufacturers of this cylinders, and they were built for many years. They came with 1/2" tapered pipe thread, 3/4" straight pipe thread, and some even had 1/2" straight pipe threads (mostly Sportsways).
Out of all my 72's one in particular is taller than the rest. There are also other smaller variations.

 

[DawsonDownUnder]

Wow. Thanks for that feedback.

I measured the tank and it's 65cm X 17cm (6.7x25 inch)

Also included a photo for context.

I take it a dive store will be able to confirm this for me too?

 

[Luis H]

Wow, that quote (from @-JD- ) is from a post from 2006.

I look at the data from that manual and when I see the capacity shown as 71.55 cu.ft., I have laugh. Showing that kind of precision is right down ridiculous. Since that post I have actually measured most of my steel 72 and not a single one has that capacity. The majority (and the average) are actually under 71 cu.ft.

 

[Pressurehead]

LP72 , is it in test and stamped? I see you are in Australia, the rules for testing cylinders in Australia are not the the same as USA or Europe.
Here is mine [a 1972- 72] half full of air but now out of test. buy a new 12.2 steel and be done with it, they are not that expensive for what you get and if [when] the 72 fails [if you can find a test station to test it] you will not be out of pocket and have brand new cylinder, remember it's "LIFE SUPPORT" not an add on .

 

[DawsonDownUnder]

Yep the Tank is in test.. until April 2021 Just trying to confirm the capacity which is looking more and more likely to be a 12Ltr

 

[Pressurehead]

Ok, good, where did the previous owner have the test done , also can you do a close up of the test stamp please?

 

[Julius SCHMIDT]

If a 12.2l Faber is a 100cft what is a 72cft tank
I would try answer but my fingers are all seized up from work this morning and my brain hurts with numbers

 

[DawsonDownUnder]

Ok, good, where did the previous owner have the test done , also can you do a close up of the test stamp please?

There is a small stamp with the test date on it with 01/04/20 What other additional information should I be looking for on the tank? The diveshop used was a local (Western Australian) shop. All other information that's on the tank is provided in the photo in my first post.

 

[Julius SCHMIDT]

Yeah but he asked for a photo please and providing photos of the markings on tanks necks is the standard and usually yields better results and people like pertinent photos especially from those requesting information as a common courtesy and I bought two tanks recently that had been repainted with home printed stickers and forged stamped test stamps that's all