VIP on AL cylinders = stupid $$$ game

[fire_diver]

If you own your own tank and dive say 2 dives a week thats 104 dives a year.....

Here's the problem with your math. you are basing this on owning A tank, not TANKS.
Paying someone else to serice your gear is fine when you own one set. What about when you have 4 single tanks, 3 stage/deco tanks and 2 sets of doubles? Still want to pay someone else 11X what you're paying now? It's been said before, this isn't rocket science. You can do it yourself. Doing your own work also lets you know it was done right, not done by a "tank monkey" or someone in a hurry to go home.

Same thing goes for reg servicing (different thread I know). People who one one reg have little room to complain about people who own 5 or more regs wanting to be able to buy parts and get proper training.

Hmmmm, what should I do? Pay someone $600-700 to service my gear, or learn to service it myself and save tens of thousands over the life of my diving.

FD

 

[Crazy Fingers]

Someone has yet to tell my why I have hundreds of STEEL breathing air cylinders at work, some 70+ years old, that don't get yearly VIPs, are filled hundreds or thousands of times from scores of different compressors (many surely in poor maintenance), that don't seem to have a problem exploding. All they get is a hydro every 5 - 10 years.

 

[Azza]

I have failed 20 or more ali tanks on visuals. Cracks around the necks being the main problem.

 

[captain]

Someone has yet to tell my why I have hundreds of STEEL breathing air cylinders at work, some 70+ years old, that don't get yearly VIPs, are filled hundreds or thousands of times from scores of different compressors (many surely in poor maintenance), that don't seem to have a problem exploding. All they get is a hydro every 5 - 10 years.

Most industral breathing air cylinders are not fill with an air compressor. They are filled by mixing oxygen and nitrogen that has been distilled from the air by a cryogenic process and has zero moisture.

 

[cummings66]

Someone has yet to tell my why I have hundreds of STEEL breathing air cylinders at work, some 70+ years old, that don't get yearly VIPs, are filled hundreds or thousands of times from scores of different compressors (many surely in poor maintenance), that don't seem to have a problem exploding. All they get is a hydro every 5 - 10 years.

Your post is funny. First off you didn't ask about this, second how are we to know?

Now, tell us exactly what usage and environment those cylinders are used in, how much pressure they're under and maybe you would have an answer, we can't read your mind since it's all over the place here.

I.e. you claimed in your first post that you could see why steel has to be VIP'd and now you present evidence that steel cylinders are able to be used for decades without issue. You also are pretty out of the loop for whatever the tanks are used for, i.e. you don't know the compressor history, tank history of how many times they get filled. There's a HUGE difference between hundreds vs thousands, which is it?

Get your facts together and come back and post it and maybe somebody can give you a good answer.

One thing I'd point out is that my O2 tanks for welding are under much less pressure than the Scuba tanks are.

 

[drew52]

Here's the problem with your math. you are basing this on owning A tank, not TANKS.
Paying someone else to serice your gear is fine when you own one set. What about when you have 4 single tanks, 3 stage/deco tanks and 2 sets of doubles? Still want to pay someone else 11X what you're paying now? It's been said before, this isn't rocket science. You can do it yourself. Doing your own work also lets you know it was done right, not done by a "tank monkey" or someone in a hurry to go home.

Same thing goes for reg servicing (different thread I know). People who one one reg have little room to complain about people who own 5 or more regs wanting to be able to buy parts and get proper training.

Hmmmm, what should I do? Pay someone $600-700 to service my gear, or learn to service it myself and save tens of thousands over the life of my diving.

FD

Yearly visual inspection of modern aluminum cylinders is stupid, and yet another dive industry scam to make money. In an aluminum cylinder which does not oxidize beyond a monolayer, "rust" isn't really a concern. I think it's left over from the days when every tank was steel and interior rust could theoretically cause corrosion from the inside and failure of the cylinder. Once the industry moved over (mostly) to aluminum tanks, why stop the requirement if it gets you $15-20 per tank per year?

No one said you had to pay someone to do all that and definatey learning to do it yourself makes sense when you get to that point in diving. Why do you think I've learnt all this stuff. But I guess you didn't come out whining about the cost of servicing a tank as it seems the original poster did. You at least acknowledge the need for doing these things. You've just taken the smarter route by learning it yourself.

For those that do recreational diving and own 1 or maybe 2 tanks and possibly 2 regulators these costs are minimal.

 

[Crazy Fingers]

Here is some information from my pals at DOT...

TITLE 49--TRANSPORTATION

CHAPTER I--RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION, DEPARTMENT OF
TRANSPORTATION

PART 180--CONTINUING QUALIFICATION AND MAINTENANCE OF PACKAGINGS
--Table of Contents

Subpart C--Qualification, Maintenance and Use of Cylinders

Sec. 180.205


(f) Visual inspection. Except as otherwise provided in this subpart,
each time a cylinder is pressure tested, it must be given an internal
and external visual inspection.
(1) The visual inspection must be performed in accordance with the
following CGA Pamphlets: C-6 for steel and nickel cylinders
(incorporated by reference; see Sec. 171.7 of this subchapter); C-6.1
for seamless aluminum cylinders (incorporated by reference; see
Sec. 171.7 of this subchapter); C-6.2 for fiber reinforced composite
special permit cylinders (incorporated by reference; see Sec. 171.7 of this
subchapter); C-6.3 for low pressure aluminum cylinders (incorporated by
reference; see Sec. 171.7 of this subchapter); C-8 for DOT 3HT cylinders
(incorporated by reference; see Sec. 171.7 of this subchapter); and C-13
for DOT 8 series cylinders (incorporated by reference; see Sec. 171.7 of
this subchapter).
(2) For each cylinder with a coating or attachments that would
inhibit inspection of the cylinder, the coating or attachments must be
removed before performing the visual inspection.
(3) Each cylinder subject to visual inspection must be approved,
rejected, or condemned according to the criteria in the applicable CGA
pamphlet.
(4) In addition to other requirements prescribed in this paragraph
(f), a DOT specification or special permit cylinder made of aluminum alloy
6351-T6 must be inspected for evidence of sustained load cracking in the
neck and shoulder area in accordance with the cylinder manufacturer's
written recommendations, which must be approved in writing by the
Associate Administrator.

---------------------------

So, DOT doesn't seem to think that we need visuals any more often than the visual which is legally required during hydrostat, which is 5 years in this case. CGA C-6.1 (which I do have on my hard drive but will not quote since it is a copyrighted material), which is hydrostat testing methods and visual inspection of high pressure aluminum cylinders also doesn't require it any more often than during the requalification, although it does note that the SCUBA industry has chosen to regulate itself more strictly than required.

Interestingly enough, it talks about sustained load cracking in AL-6351 cylinders... it says that the visual done during the 5 year requalification period is frequent enough to catch the very slowly developing cracks, provided that the visual is done thoroughly.

 

[Crazy Fingers]

Your post is funny. First off you didn't ask about this, second how are we to know?

Now, tell us exactly what usage and environment those cylinders are used in, how much pressure they're under and maybe you would have an answer, we can't read your mind since it's all over the place here.

I.e. you claimed in your first post that you could see why steel has to be VIP'd and now you present evidence that steel cylinders are able to be used for decades without issue. You also are pretty out of the loop for whatever the tanks are used for, i.e. you don't know the compressor history, tank history of how many times they get filled. There's a HUGE difference between hundreds vs thousands, which is it?

Get your facts together and come back and post it and maybe somebody can give you a good answer.

One thing I'd point out is that my O2 tanks for welding are under much less pressure than the Scuba tanks are.

You're one of the more fun people around here.

If you could read better you would have seen that there were hundreds of cylinders, some made in the 30s, some made post 2000. So how can I generally say how many times they have been filled? You are not required to log cylinder fills unless the cylinder is emptied more than every other day. (DOT requirement). So no, nobody knows how many times they have been filled. But it is extremely probable that a large percentage of them have been filled hundreds or thousands of times.

As for my statement that steel needs yearly VIP, and aluminum only during hydro, I still stand by that. My purpose in pointing out that the above referenced cylinders were steel was to show that over decades and decades of use, with lots of fills, even steel (which is more prone to corrosion than aluminum) is fine without visuals all the time.

 

[Crazy Fingers]

Most industral breathing air cylinders are not fill with an air compressor. They are filled by mixing oxygen and nitrogen that has been distilled from the air by a cryogenic process and has zero moisture.

Fair enough. This sounds like a damn good answer to my question. Thanks.

But I still stand by the DOT and CGA requirements, which is a visual every 5 years during hydro. Because these requirements do not differentiate between cyrogenically distilled air or compressed atmosphere.

 

[JahJahwarrior]

Reading all this again made me think maybe my backpack for school needs a VIP. It'd probably fail, there are some cracks in one of the straps. Honestly, Is hould have gone with the 6061 backpack, instead of the older 6351. My bag is just about due for it's hydro (less than a year left on last hydro) and I don't know if it will pass. My teachers don't seem to care though, they'll make me fill it. Fortunately, books aren't as compressable as air, so if something does crack or it explodes, nobody except me will get hurt.