Hydro Testing? what do they look for?

Matster22 · 07-15-2010, 10:05 AM

I'm about to buy a used HPA tank. It's out of hydro and I was wondering what kind of damamge people look for when hydro the tank.

uranjack · 07-15-2010, 11:26 AM

To pass a hydro test the tank must not be unraveling. (If it carbon fiber.) There shouldn't be any huge chunks of plaster gone (IE: Invert tanks have a white plaster covering them) To pass a tank though the tank must not expand passed its limits. They pipe water into the tank then air, they check to see how much it expand then if it passes they put a new label on it and give it back. If it fails they drill holes into it so it can never be used again. If the tank you are buying is not a Carbon fiber Blank/4,500 Tank it is not worth getting it hydro tested.

Jeremy @ Ninja · 07-15-2010, 01:31 PM

Quote:

Originally Posted by uranjack

To pass a hydro test the tank must not be unraveling. (If it carbon fiber.) There shouldn't be any huge chunks of plaster gone (IE: Invert tanks have a white plaster covering them) To pass a tank though the tank must not expand passed its limits. They pipe water into the tank then air, they check to see how much it expand then if it passes they put a new label on it and give it back. If it fails they drill holes into it so it can never be used again. If the tank you are buying is not a Carbon fiber Blank/4,500 Tank it is not worth getting it hydro tested.

That's close. We never use air in hydrotesting though, only water pressurized to the correct test pressure. And also, a hydrotesting facility needs your approval to render the cylinder incapable of holding air. You can request they simply label the tank Condemned instead of drilling the hole. Although the drilling is kind of fun...

The main thing to watch for is any visual damage. Look for scratches, abrasions, cuts or anything externally that may damage the fiber layer. Now the damage does have to go into the fiber layer for it to be of any concern, the gel coat over the tank can be in horrible condition and it will still be fine. For aluminum tanks, same thing. Any cuts, dents or scratches can cause the bottle to fail, depending on the depth.

The other main problem which cause tanks to fail is the bottle threading. If the threads are damaged in anyway, there's pretty much no hope for the bottle. And depending on who installed the reg, they may have used loctite and that can cause issues when removing the reg. 99% of the time, they come out fine, but there is the occasion where a reg will lock up and not come out.

As far as worrying about the expansion, I don't think we've ever failed a tank due to it not passing the actual hydrotest.

canemaster · 07-21-2010, 12:13 PM

Yea I've been playing with a tank that's been out of hydro for 4 years now. As long as there is no damage to the bottle or threads, should be fine

Tabris17 · 07-21-2010, 12:21 PM

Quote:

Originally Posted by canemaster

Yea I've been playing with a tank that's been out of hydro for 4 years now. As long as there is no damage to the bottle or threads, should be fine

What? Are you seriously that inconsiderate of the federal law and the safety of yourself and others that you would do this? I honestly can't begin to fathom the thought process that lets you believe it's totally okay to do this.
The hydro test is to ensure that the structural integrity of the tank is still intact and the expansion and contraction is within the safety limits. How many times have you heard that a bridge was 'okay' based on a visual inspection and then it collapsed months later because of 'unseen internal damage'?

killerWGP212 · 07-21-2010, 12:28 PM

Quote:

Originally Posted by Tabris17

What? Are you seriously that inconsiderate of the federal law and the safety of yourself and others that you would do this? I honestly can't begin to fathom the thought process that lets you believe it's totally okay to do this.
The hydro test is to ensure that the structural integrity of the tank is still intact and the expansion and contraction is within the safety limits. How many times have you heard that a bridge was 'okay' based on a visual inspection and then it collapsed months later because of 'unseen internal damage'?

Down Tabby, just let natural selection run its course and weed out the weak and stupid that fail to evolve into something productive

f8user · 07-21-2010, 12:43 PM

Quote:

Originally Posted by killerWGP212

Down Tabby, just let natural selection run its course and weed out the weak and stupid that fail to evolve into something productive

this is sigable

canemaster · 07-21-2010, 01:09 PM

Structural integerty is fine as long a no visible damage is apparent.
It is possible that the expansion and contractions could be severe enough to fail the test but unlikely. Even more unlikely is that it would be severe enough to compromise the tank's structural strength. So yea, let nature run it's course and leave more money in my pocket and not wasted..

Tabris17 · 07-21-2010, 01:22 PM

You seem to be missing my point that there can be damage even if there is nothing visible, hence the test to ensure it.
Do what you want though, you obviously have absolutely no regard for your safety and the safety of others around you over the sake of a few dollars every five years. That's an inexcusable compromise and I sincerely hope you never get somebody injured or killed due to your willful negligence as I find it disturbing and disgusting you would gamble with others safety and be so casual about it.

DSDM · 07-21-2010, 01:44 PM

Quote:

Originally Posted by Tabris17

You seem to be missing my point that there can be damage even if there is nothing visible, hence the test to ensure it.
Do what you want though, you obviously have absolutely no regard for your safety and the safety of others around you over the sake of a few dollars every five years. That's an inexcusable compromise and I sincerely hope you never get somebody injured or killed due to your willful negligence as I find it disturbing and disgusting you would gamble with others safety and be so casual about it.

What is more disturbing than all of that is that the fields are letting this kind of thing go. If they only knew/cared about the fines they face if they get caught or an accident happens.

canemaster · 07-21-2010, 01:50 PM

I appreciate your concern and I assure you if anything were to happen, it would be to me and no one else..

I planned on hydro testing it soon but it's not high on my priority list.

I understand you are very knowledgeable on this subject and I respect that but I've had some scuba experience.
Carbon fiber tanks have a service of about 15-16 years. They are stronger that steel tanks and we tested our steel tanks every 5 years.

The main step for longevity is to fill your tank slowly and I have always filled every single one of my tanks very slowly.

I wasn't encouraging the OP to not get his tank tested. I was merely showing him that modern tanks are very strong and safe.

And I find it funny that you used the adverb "disgusting" haha. Really? Is it really disgusting?

Jeremy @ Ninja · 07-21-2010, 01:52 PM

Quote:

Originally Posted by canemaster

Structural integerty is fine as long a no visible damage is apparent.
It is possible that the expansion and contractions could be severe enough to fail the test but unlikely. Even more unlikely is that it would be severe enough to compromise the tank's structural strength. So yea, let nature run it's course and leave more money in my pocket and not wasted..

So what happens when your field gets caught filling an out of date tank and they now owe D.O.T. $10,000? What happens if someone else is filling your tank and it injures or kills them? Is saving 30 bucks that important to you? D.O.T. has reasons for their testing schedule and that's why it is a federal law, not a suggestion.

canemaster · 07-21-2010, 02:09 PM

First off you are making the assumption that I use this tank regularly at my field. You are also assuming that other people fill my tank...

I am the only one who fills my tanks. I fill them myself at home (scuba) or myself at the field (self serve station).
And the last time I took this tank to my local field was almost 2 years ago.

DSDM · 07-21-2010, 02:25 PM

Quote:

Originally Posted by canemaster

Yea I've been playing with a tank that's been out of hydro for 4 years now.

+

Quote:

Originally Posted by canemaster

First off you are making the assumption that I use this tank.... at my field......the last time I took this tank to my local field was almost 2 years ago.

= Assumption confirmed

Just let me know what field you use so I can make sure I never play there.

Quote:

Originally Posted by Jeremy @ Ninja

So what happens when your field gets caught filling an out of date tank and they now owe D.O.T. $10,000? What happens if someone else is filling your tank and it injures or kills them? Is saving 30 bucks that important to you? D.O.T. has reasons for their testing schedule and that's why it is a federal law, not a suggestion.

Jeremy you are bouncing your head off the wall. It is the "Me" generation that you are talking to; It will always be about "Me" with them.

Tabris17 · 07-21-2010, 04:33 PM

Quote:

Originally Posted by canemaster

I appreciate your concern and I assure you if anything were to happen, it would be to me and no one else..

I planned on hydro testing it soon but it's not high on my priority list.

I understand you are very knowledgeable on this subject and I respect that but I've had some scuba experience.
Carbon fiber tanks have a service of about 15-16 years. They are stronger that steel tanks and we tested our steel tanks every 5 years.

The main step for longevity is to fill your tank slowly and I have always filled every single one of my tanks very slowly.

I wasn't encouraging the OP to not get his tank tested. I was merely showing him that modern tanks are very strong and safe.

And I find it funny that you used the adverb "disgusting" haha. Really? Is it really disgusting?

Can you give the same assurance that if you're handling a grenade or a bomb or anything else that stores potential energy that you would be the only one harmed if something were to go wrong? No, I really doubt you can. These tanks hold 3000-4500 psi in a very small cubic area, that is a lot of stored energy just waiting to come out; it is a bomb in that regard.
And yes, I do find it disgusting you would put not only yourself but others around you at the fill station and the field at such a risk over a $30 fee that pops up every five years. You can make every excuse and come with every reason you want but the bottom line is that your actions are improper, unsafe, and wrong.