VIP Inspectors: Identifiable vs Identified

[rjack321]

Can anyone give 1 example in the last ~5-10 years that a tank was condemned within the 5 years after a hydro (which means the hydro must have been done in the last 5-10 years)? I'm just curious if the VIP that used to be from a safety standpoint has now turned into a "tax" from an LDS?

I have condemned an AL80 for pitting which was still a few years away from hydro. I.e. the pit formed in ~2 years.
Tanks taken underwater do require more frequent inspection, its a harsh environment and salt water is pretty corrosive. Was that pit going to lead to a catastrophic failure right away? Probably not but I don't think waiting another 3 years for the hydroshop VIP to fail it was prudent either.

 

[markmud]

Individuals participating in the VIP system are being viewed with distrust because there is no reciprocity.

Hi Jeremy,

There most certainly is reciprocity. The individuals followed the industry guidelines for successfully getting trained to VIP tanks. RSTC, TDI, and PSI deserve reciprocity for their training services through their individual VIP cert holders. I think it is appropriate for an LDS to perform spot checks on cylinders that are VIPed by an unknown source. But, flat out reject the VIP is ludicrous. Pop the cork and look inside the tank. That's all it takes.

Good point.

It does seem reasonable to put an ID on the sticker that ultimately links to the person who performed the VIP.

How about I just show my VIP cert and tank inspection records instead. Verification of bona fides is OK. The certification system needs to be honored. Holier than thou hot shots making arbitrary decisions, like the soup Nazi on Sienfeld, hurts the industry. Like a dive op who doesn't allow an MSD and a Tech 40 cert holder to dive an intermediate or advanced recreational dive site in optimum conditions. Same issue, different circumstances.

They shop will accept a Nitrox fill by showing a cert card without you sitting one of their exams.

Exactly!

I think too much weight is placed on the Vis inspection as it doesn't prove the cylinder can hold pressure or even that its safe to fill.

It only shows that on the day of inspection nothing problematic was seen

I totally agree. It is a snapshot in time that is no longer valid after the sticker is placed on the tank. A steel tank can suffer lots of damage if salt water finds it way into the tank the day after a VIP. An AL tank may develop cracks the day after a VIS. The only true test is a hydro. However, those are rare cases that prove the rule. 99% of tanks that aren't abused don't need a yearly vis.

That does make some sense to me. Reciprocity requires that both parties not only inspect tanks but also fill tanks.

Your reply to Jeremy Williams is totally correct. A certified inspector that was trained to diving industry standards should be given reciprocity. Being asked to show "your papers" is valid. Having the cork removed from the tank for a quickie VIS is OK. The certification regime that exists in the SCUBA industry must be honored.

Of course, we have been educated in this thread that inspection seems to be less about fill operator safety than it is about making money.

Or something else, maybe undeserved fear or ego.

cheers,
markm

 

[lowviz]

The point is that I don't think passing hydro is necessarily an indication that the tanks will pass a shop VIP.

Interesting. Also very believable as I would expect that there is a 'safety factor' in the determination of pit depths or line pitting or cracks, or whatever. What is the presupposed safety factor? For airline aluminum it is (IIRC) only 3.

In that light, will a visible internal crack at the neck summarily condemn an aluminum tank? Such is why I still believe that I got a real education in what I will dive and what I will retire.

 

[rjack321]

Maybe not relevant to the conversation, but just a quick note that it is possible for a tank that the hydro facility presumably gave a quickie VIP before testing and giving a pass, to then fail the subsequent, presumably more thorough VIP at a dive shop. I bought some older but freshly hydro'd tanks, and when I took them to the dive shop I was informed the rust pitting was pretty bad and the tanks would likely not pass the VIP threshold for pit depth, even after aggressive tumbling. Seems to me that progressive deepening of rust pits and similar damage is more of a concern than cockroaches, etc. I returned the tanks to the seller. The point is that I don't think passing hydro is necessarily an indication that the tanks will pass a shop VIP.

Hydro testers are human like everyone else. But the CGA standard applied at the hydro shop and the dive shop should be the same. If there was pitting greater than allowable, the hydro tester should have failed this tank. The "dive shop standard" is not and should not be anymore rigorous.

Like I said earlier in this thread I mistakenly passed a 3AL2015 cylinder with a pit that I should have failed (PSI's pit depth chart led me astray). The hydro shop caught my mistake and failed it for me.

 

[Diving Dubai]

Question on tumbling

(its bugged me for years)

When a tank is tumbled, is it marked in anyway? Is there a limit to the amount of tumbles you can make or can you do them to your hearts desire until it fails hydro?

Given tumbling reduced by nature the material wall thickness - if you are tumbling to remove pits, are you more concerned with the pit being a stress initiation point or that its a local reduction in material wall thickness?

 

[lowviz]

Like I said earlier in this thread I mistakenly passed a 3AL2015 cylinder with a pit that I should have failed (PSI's pit depth chart led me astray). The hydro shop caught my mistake and failed it for me.

It was -beat into us- that we go to the online updates on a regular basis.

 

[rob.mwpropane]

Question on tumbling

(its bugged me for years)

When a tank is tumbled, is it marked in anyway? Is there a limit to the amount of tumbles you can make or can you do them to your hearts desire until it fails hydro?

Given tumbling reduced by nature the material wall thickness - if you are tumbling to remove pits, are you more concerned with the pit being a stress initiation point or that its a local reduction in material wall thickness?

My experience with steel says tumbling would not remove pits as much as clean them. I don't think any amount of tumbling (within reason) would wear down the walls of a tank (if the correct media is used). It would clean and hopefully prevent the pit from getting worse.

Someone correct me if I'm wrong....

 

[rjack321]

Question on tumbling

(its bugged me for years)

When a tank is tumbled, is it marked in anyway? Is there a limit to the amount of tumbles you can make or can you do them to your hearts desire until it fails hydro?

Given tumbling reduced by nature the material wall thickness - if you are tumbling to remove pits, are you more concerned with the pit being a stress initiation point or that its a local reduction in material wall thickness?

Anything that thins the tank wall is prohibited. Sand blasting paint off is the most obvious example.

Tumbling does not remove intact material, it is removing corrosion / oxidized material yes. Basically if there are pits or corrosion it fails for those (post tumble since you can see them) but you cant tumble a tank so much as to actually remove solid metal to the point of thinning the walls. There are ultrasonic ways to non-destructively measure wall thickness and @Luis H has actually done this for other reasons (he was proving his 72s were suitable for a + rating). But there's no real need to examine wall thickness because tumbling doesn't thin walls

 

[rjack321]

It was -beat into us- that we go to the online updates on a regular basis.

In my case it was an erroneous table not something that changed in the actual standards.

 

[lowviz]

...not something that changed in the actual standards.

Ah, I misunderstood.