for those with Steel 72s...

[Couv]

....But finding a hydro shop that can get the REE number, and will take the time to do this, and will issue a plus rating, is tough, at least in my experience.

Attached is the PST REE document-it may help.

 

[apenland01]

Unfortunately, my Norris tank has an unlisted REE, so it will never have a plus outside of it's original plus rating at the date of initial hydro...

 

[runsongas]

can check with @Luis H if he calculated it out for norris, iirc he did the actual math for some of the vintage tank types

 

[captain]

can check with @Luis H if he calculated it out for norris, iirc he did the actual math for some of the vintage tank types

Having the number is one thing, having the hydro facility accept it without official documentation from the is the problem. I personally know Luis but telling a shop this is the REE my friend Luis calculated ain't going to fly very far.
I fill my own tanks and know how to calculate if my tanks qualify for the plus using the results of the hydro so having a + stamped into the tank is not an issue.

 

[rjack321]

Those are seen as 3K tanks anywhere on the East Coast (USA) that I have ever come in contact with. Give me one reliable example of one of them asploding due to the 750 psi overfill. One of my treasured 72's is stamped EBD. (The first woman on the Doria.) I can't imagine how many times that tank has been filled to 3k cold.

I'm only limited to a 2250 fill for pure O2 and have absolutely no issue with that whatsoever.

A young nitwit at Dutch Springs took delight in limiting me to 2250 on air. I live in Delaware. Ever since then, I drive north the same distance to dive. But now I turn in the other direction to one of the ocean's back bays to solo watch the critters with a full fill from my new LDS instead of soaking in a carnival pisshole quarry.

72s are the only steel tanks I have seen split (explode). Not due to a 3k fill, more due to thin walls not providing much reserve for corrosion. Combined with the old epoxy liners and even the plastic bladders of yesteryear, poor filters and fill practices, and sometimes sitting for decades with moisture inside - they seem to be the only steel tanks reported to have catastrophically failed.

In hydro in vis I fill mine to 2800ish. If an unknown ever showed up at my home fill station I would probably peek inside before filling unless I knew it was recently opened and vized

 

[lowviz]

72s are the only steel tanks I have seen split (explode).

When/Where/Pics?

Not due to a 3k fill, more due to thin walls not providing much reserve for corrosion.

IMHO you are being a bit unfair to these tanks. The wall thickness does provide a very good reserve for corrosion. Are pitting (spot, area, line) specs reduced for steel 72's?

Combined with the old epoxy liners and even the plastic bladders of yesteryear, poor filters and fill practices, and sometimes sitting for decades with moisture inside - they seem to be the only steel tanks reported to have catastrophically failed.

"They seem to be" is a bit too vague for me. All the above is taken into account by anyone who is both certified to perform VIPs and takes his or her obligation seriously.

In hydro in vis I fill mine to 2800ish.

OK, fine. How high does your compressor go?

 

[rjack321]

When/Where/Pics?

Are you saying these failures don't exist? One was in the shop at PSI where i took my VIP course 15 yrs ago.

The pit limits for 72s are not reduced compared to other 3AA cylinders, but the wall thickness is less. The reality is that these cylinders have been around and often stored with moisture in them far longer than any other steel scuba cylinders - so its not some amazing revelation that in 60+ years of service there have been more failures in 72s than in 3442psi exemption tanks that have only been in existence for 20 years - an era with far more modern compressor filtration standards.

 

[runsongas]

Having the number is one thing, having the hydro facility accept it without official documentation from the is the problem. I personally know Luis but telling a shop this is the REE my friend Luis calculated ain't going to fly very far.
I fill my own tanks and know how to calculate if my tanks qualify for the plus using the results of the hydro so having a + stamped into the tank is not an issue.

the specifications for + rating determination are published and if you show the long form calculations, a good hydro facility can quickly verify the numbers. they don't have to be from the OEM as they are baked into the 3AA specification, it is just convenience that they are boiled down to the REE

 

[lowviz]

Are you saying these failures don't exist? One was in the shop at PSI where i took my VIP course 15 yrs ago.

My point. How many 72's passed through there before and since?

The pit limits for 72s are not reduced compared to other 3AA cylinders, but the wall thickness is less.

Agree. Annnnnnnd??? Design always involves strength of materials...

The reality is that these cylinders have been around and often stored with moisture in them far longer than any other steel scuba cylinders - so its not some amazing revelation that in 60+ years of service there have been more failures in 72s than in 3442psi exemption tanks that have only been in existence for 20 years - an era with far more modern compressor filtration standards.

I see the above as a bit of a deflection from the subject in question, but you and I (doing our jobs VIP'ing cylinders) keep this issue under control enough that our sport is very lightly federally regulated.

 

[lowviz]

@rjack321, final thought. We both know this but the idea needs to be kept fresh in our community:

NOBODY (other than a hydro site) doing a VIP can either condemn or stamp anyone's tank. However, we can 'reject'.

That means you get your tank/cylinder back alive, but the person who did the VIP refuses to pass it. No problem, send it to hydro...