Vintage Double Hose

- I low-balled a bid on a set of Sportsways Twin 42s with the 1/2" O-Ring valves. Nobody else bid on it and I was suspecting something was wrong or that these tanks had a reputation. I took a shot at it thinking if I pay a low enough price, it would get me a single 42 in the worst case scenario.

- Well, they ARE a matched set and both are undamaged 1/2" O-Ring threaded. Valve and yoke looks very nice. I took off the boots and there's no external rust or pitting.

- However, inspection of the insides reveals one tank is in excellent, brite metal condition and one is in VERY corroded condition. I'm going to check into tumbling the bad one to see if it's in better shape than it looks. BUT, I have a 1/2" O-Ring Sportways 42 I bought from Rob. So, I can make this into a fine set of double 42s even if the corroded tank turns out to be unusable.
Second Look July 11th
- Funny the difference a proper light source can make. I found a little Maglite that I could hang down through the 1/2" opening and get a better look. The stuff I thought were pits were just rust spots with a shiney surface. It now looks like its only surface rust and otherwise no pitting.
- So, maybe I got a bargain afterall. We'll see after cleanup and hydro!

Screwed, Blued, and Tatooed...
- Alas they flunked the Hydro test. So, I got a 1/2" O-Ring Twin Tank Valve and a Twin Tank Back Pack out of the deal... But the tanaks are no good.

Did they do the pre-test procedure for galvanized tanks?

Did they xxx-out the DOT numbers or did they just tell you that it failed?

You should request the hydro test data. The test data is property of the DOT (as in public data) and they are required to provided if requested.

The reason I ask is because I am very suspicious when I hear of two 3AA code tanks failing. Yes, they probably had the same life history, but unless they where in a fire together, the probability of two 3AA tanks failing on the same day is very unlikely... unless they didn't follow the proper pre-test procedures.

Can you tell if the tanks are galvanized under the outer coating? I was thinking that SW galvanized all theirs even when painted. If so, this could be yet another case of a hydro facility not knowing how to properly test a galvanized cylinder.
The required method is slightly different, and is not well known by all testers since they only run into the occasional dive cylinder that is galvanized. 99.99% of the cylinders they test are not. This is a recurring problem that has cost divers a lot of lost cylinders that may have been good if tested properly!

Please check out what is under the paint and let us know.
I sent the hydro testing info for Galvanized Cylinders to VDH several years back, and it is posted in the Manuals and Catalogs section.

If your tanks are galvanized, you should take a "morning-after pill", cause you have probably been screwed! Steel tanks just hardly ever fail hydro.

- Okay, so this is what tanks look like when they come back after failing a hydro test. They didn't XXX out anything... Just didn't add a new test date. The LDS that sent these in said the Hydro guy was on the phone with him during the test and said something like "These tanks a stretching like crazy".
- They are definitely galvanized... I took off the orange paint on one with acetone and steel wool and it is bright galvanized.
- I read the info on preparing Galv cylinders... It sounds like early galvanized cylinders will definitely fail hydro if that procedure is not followed. And BOTH failed. Hmm...
- Question: Could the non-galv hydro procedure damage the tanks?

It sounds like the hydro guy does not know what he is doing. IF the cylinders failed they are required to be xxxx out or stamped "condemned". Spray painting "FAILED" does not stop someone from removing the paint and still using or selling them. All that being said it is standard procedure at my shop to do a "pretest" on ALL steel cylinders. That involves bringing the cylinder to 90% of actual test pressure and taking out some of the stretch.
PST requires a "pretest" on all of their cylinders, Worthington requires two "pretests".
Norris cylinders typically have a lot of stretch on the "pretest" and most pass the actual test if they have not been abused. DOT does not require a "pretest" on any steel cylinders. The only steel cylinders that have different testing procedures authorized by DOT that I know of are Worthington SP14157.

SurfLung wrote:
- Okay, so this is what tanks look like when they come back after failing a hydro test. They didn't XXX out anything...

- Question: Could the non-galv hydro procedure damage the tanks?

This is potentially great news for you since they didn't properly condemn the cylinders. I really don't see how there could be any damage from the test itself... it just shows why the "roundout" procedure must be used on galvanized cylinders before the actual test to full test pressure is applied.

You have a second chance to have these done properly, and a good possibility of them passing. The challenge might be finding someone that will actually follow the prescribed test procedure. Maybe there is a forum member in your general area that knows a facility that can and will test your cylinders properly... or maybe if you go direct to the previous tester with the printed info they might be willing to comply if diplomatically educated. (Or you can drive them to north-central Texas where I know two facilities that comply with the proper test).

Sounds like their stupidity of the regulations saved you. You might consider posting who they are to avoid someone else here from experiencing the same thing.

- I've been doing some checking around and thinking before replying to Captain's suggestion. I got a detailed reply from a large cylinder servicing company who said "As far as the galvanized cylinders, there are a lot of people who say that they can be “pre stretched” to 90% of test pressure and then tested. There is no written document in the DOT CFR49 that says that procedure is acceptable, it does state that if you can run a test on the equipment to verify accuracy of equipment by running it up to 90% of test pressure". I had sent him a copy of the Pressed Steel Instructions that referenced DOT 49 CFR 173.34 (e)(4)(y). He changed my wording of "Pre-Test" to "Pre-Stretch" in every reference. He also stated "If we pre-stretched all cylinders, all of them would pass...". Finally, he said a failed cylinder should have the DOT ratings stamped out and the threads rendered useless. The email has a confidentiality notice at the bottom and I will respect that out of appreciation for his honesty in answering my questions... Even though its not the answer I had hoped for.
- The same questions to a local dive shop owner I know pretty well came back with the following:
"I have had 4 tanks fail the hydro test. Three of them I could identify myself, I could see the cracks (aluminum? - Eb). The other one was a 2250 tank and I knew there was nothing wrong with it, so I sent it to a different hydro place and it passed. I’m sure they tested it as a 3000 tank & that’s why it failed at the first place. I guess it’s your call if you want to spend the money. But, they really are trying to get all these odd number psi tanks off the market. They just want the standard tanks to be 2250 or 3000 psi. It’s a lot of work to switch their machines to test these different tanks." (So the industry may be pre-disposed to failing our vintage 1800 and 1880 psi tanks?)
- Rather than post the "Not Recommended" Hydro Testers, I think I will keep searching and post a positive recommended facility when I find one. There ARE some others in MN... Stay Tuned...

At one time I had found a video and can't recall who made it, I think it was XS Scuba but not sure. It gave a very detailed explanation with video graphics how hot dip galvanizing affects the tank and why the pre stretch is needed. I will look again to see if I can find it. The pre strech only applies to hot dipped galvanized tanks, not all tanks. I think the best thing for someone to do with any tank that has been empty for a while and need a hydro is to look inside first, if there is only minor signs of rust, fill it to working pressure with a transfill whip and take it full to the hydro shop. That is what I would do.

Here is the list of testers by state. Bryan, this should be in the downloads section if it isn't already or a sticky at the top of the tank section. I might also add that if the tester doesn't do the pre test to confirm there are no leaks it will also probably fail.

http://www.phmsa.dot.gov/portal/site/PH ... tfmt=print

Just found this.


http://www.xsscuba.com/cylinder_info.html

I have had conversations with DOT several times over the years on various issues relating to tanks. They have always been helpful. You can request a letter of clarification on the hot dipped galvanized cylinder test revisions as to if they apply retroactively to all galvanized cylinders. Send them a email and include your phone number they will either reply by email or call you, usually they called me and discussed the issue and you can ask for a clarification letter.

http://www.phmsa.dot.gov/

The Fear Factor...
- Businesses these days have a lot of fear regarding liability in law suits as well as erroneous interpretation of government regulations. It's easier to say "No" than to stick your neck out to please a customer for so little money.
- I got another email from the big hydrotestor in which he said the 49 CFR 173.34 wording is interpreted erroneously and if I were to read it, I would agree. So, I looked it up and here is what it says:
49 CFR 173.34(e)(4)(v)
(v) Minimum test pressure must be maintained for at least 30 seconds, and as long as necessary for complete expansion of the cylinder. A system check may be performed at or below 90% of test pressure prior to the retest. In the case of a malfunction of the test equipment, the test may be repeated at a pressure increased by 10 percent or 100 psi, whichever is less. This paragraph (e)(4) does not authorize retest of a cylinder otherwise required to be
condemned under paragraph (e)(6) of this section.
- His argument is that this wording is about calibrating his equipment. And, I have to agree it isn't presented as a special procedure for galvanized tanks... It reads as an optional, unrequired "System Check".
- However, the regulation is simply saying the System Check procedure is an acceptable practice. And if the manufacturer recommends using the DOT accepted System Check procedure, why wouldn't the hydro tester just do it that way?

Did you watch the video, perhaps the hydro shop should also watch it.http://vimeo.com/32271440

The DOT agrees that hot dip galvanizing affects cylinders in regard in how the usual test results may be inaccurate. The question now is will they make it a blanket retroactive change in test procedure or only in the case of Worthington cylinders. The change requires knowledge of the REE value which may be a problem. By my reading of the change it basically throws out the 10% rule and goes strictly by REE.

SurfLung wrote:-Finally, he said a failed cylinder should have the DOT ratings stamped out and the threads rendered useless.

The statement above is only partially correct.
If by “failed” he means the cylinder must be condemned in accordance to 49 CFR Ch. I, 180.205, Nt.:

(1) A cylinder
must be condemned when—

(iv) For a DOT specification cylinder,
other than a DOT 4E aluminum cylinder
or a special permit cylinder, permanent
expansion exceeds 10 percent of
total expansion.

Then the following applies:

(2) When a cylinder must be condemned,
the requalifier must—
(i) Stamp a series of X’s over the
DOT specification number and the
marked pressure or stamp ‘‘CONDEMNED’’
on the shoulder, top head,
or neck using a steel stamp;

(iii) As an alternative to the stamping
or labeling as described in this
paragraph (i)(2), at the direction of the
owner, the requalifier may render the
cylinder incapable of holding pressure.

Notice the bolded portion of the last paragraph. If a requalifier does this: “the threads rendered useless” without the “the direction of the owner”, he in essence has destroyed property without the owners authorization.

The DOT numbers belong to the DOT and therefore can be revoked (destroyed) by the DOT, but destroying the tank threads requires the owner’s authorization and it should be obtained in writing.

CFRs can be a bit confusing, but a hydro test operator should know better than talking about destroying cylinder threads without owners permission... that is inexcusable.

Note: there is a distinct difference between a cylinder that must be “condemned” from a “cylinder rejection”. Cylinder rejection is covered in 49 CFR Ch. I, 180.205 (h).

SurfLung wrote: - The same questions to a local dive shop owner I know pretty well came back with the following:
"I have had 4 tanks fail the hydro test. Three of them I could identify myself, I could see the cracks (aluminum? - Eb). The other one was a 2250 tank and I knew there was nothing wrong with it, so I sent it to a different hydro place and it passed. I’m sure they tested it as a 3000 tank & that’s why it failed at the first place. I guess it’s your call if you want to spend the money. But, they really are trying to get all these odd number psi tanks off the market. They just want the standard tanks to be 2250 or 3000 psi. It’s a lot of work to switch their machines to test these different tanks." (So the industry may be pre-disposed to failing our vintage 1800 and 1880 psi tanks?)

Your local dive shop owner has no clue of what he is talking about.

A professional hydro station (that does more than just Scuba tanks) will test cylinders of many different pressures (fire extinguishers, life raft cylinders, O2 cylinders, CO2 cylinders, argon, helium, nitrogen, etc.). Most type 3AA O2 cylinders have a stamped pressure of 2015 psi (with the + then 2216 psi). I think most CO2 cylinders are stamped 1800 psi.

From this statement: “It’s a lot of work to switch their machines to test these different tanks”, I can tell you that he has never seen how a hydro test is done. There is nothing to switch. The operator only needs to determine the test pressure for the particular tank and then he takes up to that pressure (he has to record all that information). Most hydro stations that I have dealt with have a posted table (right on the console) with all the common tank pressures with the test pressure next to it.

captain wrote:Did you watch the video, perhaps the hydro shop should also watch it.http://vimeo.com/32271440

The DOT agrees that hot dip galvanizing affects cylinders in regard in how the usual test results may be inaccurate. The question now is will they make it a blanket retroactive change in test procedure or only in the case of Worthington cylinders. The change requires knowledge of the REE value which may be a problem. By my reading of the change it basically throws out the 10% rule and goes strictly by REE.

That (highlighted in bold) only applies to the Special Permit cylinders manufactured by Worthington.

For 3AA cylinders the test procedure has not changed (the REE is only needed for the + stamping) and I don't think it will change anytime soon. I have heard of talk about revising the test procedure for 3AA cylinders to always include the 10% overfill (+ stamping), but I don't think that talk has gone anywhere.