VIP Criteria for Steel Tanks

[Ed Palma]

Hello there!

I'd like to know what the criteria for condemning steel tanks are - short of signing up for a PSI class or ordering the CGA C-6 pamphlet. I just want to do a quick run through to make sure that my tank was properly viz-ed by the inspector (nothing against inspectors, but I just want to be thorough anyway).

I remember there was a thread somewhere here that listed some criteria:
1. pits not deeper than 0.06 inches
2. line corrosion not longer than 6 inches
3. corrosion not covering more than 25% of the tank
4. signs of overheating (scorch or arc marks)
etc. etc. etc.

I can't seem to find the thread anymore!

Thanks

 

[cobaltblue]

First, VIP is a scuba industry thing. You won't find anything with the CGA. The CGA only cares that the hydro is up to date.

Oh, by the way, the hydro is really only for transporting. There are no laws that govern the filling of scuba cylinders like the LDS's would like you to think there is.

Thank God my compressor is on the way.

 

[Ed Palma]

Oh, I was under the assumption that the inspections as per the Navy Diving manual indicated inspections were to be done in accordance with CGA C-6. Anyway, not having access to it, thanks for that bit of info didn't know what was in it.
Still, I'd like to know what can condemn my tank...

 

[captain]

Oh, I was under the assumption that the inspections as per the Navy Diving manual indicated inspections were to be done in accordance with CGA C-6. Anyway, not having access to it, thanks for that bit of info didn't know what was in it.
Still, I'd like to know what can condemn my tank...

The most likely thing to condemn your tank is an incompetant inspector.

 

[Ed Palma]

The most likely thing to condemn your tank is an incompetant inspector.

Hehehe! :lol:

I'd actually prefer that. What's more worrisome is letting an incompetent inspector PASS it! Wouldn't want to use an unsafe tank.

 

[rjack321]

CGA and the manufacturers do set criteria for pits and corrosion. E.g. the scuba industry has not specified allowable pit depth. Without looking at my notes, the 4 you listed are close. However, I think the pit depth you've listed is for AL80s though, not steels. Allowable depth in E9791s is definately shallower than in 3AAs.

You also need a min # threads (varys) + a bell like tone when struck. Oh and no neck cracks.

If you don't trust your inspector, get another one.

 

[Ed Palma]

At any rate, the reason I'm also asking is to get your opinion on this:

This is a picture of the inside of my tank - i know its not the best, but it shows flash rust and some pop-corn rust. There are some pits though, and I'd just like to be sure.

 

[Ed Palma]

Okay, thing refused to edit. Anyway, here's the picture again:

 

[Hoyden]

First, VIP is a scuba industry thing. You won't find anything with the CGA. The CGA only cares that the hydro is up to date.

Oh, by the way, the hydro is really only for transporting. There are no laws that govern the filling of scuba cylinders like the LDS's would like you to think there is.

Thank God my compressor is on the way.

Where are you getting your information? The visual inspection is required every 5 years with hydro by the DOT (see 49CFR178 and 49CFR180). The Compressed Gas Association publishes CGA 6 "Standards for Visual Inspection of Steel Compressed Gas Cylinders" and CGA 6.1 "Standards for Visual Inspection of High Pressure Aluminum Compressed Gas Cylinders". In CGA pamphlet P-5 "Suggestions for the Care of High Pressure Air Cylinders for Underwater Breathing" the CGA recommends an annual visual inspection for scuba cylinders. The scuba industry is following the CGA's recommendation, not making it up on their own.

As fas as hydro being only for transporting and whether or not it applies to you, I guess you have no worries if you own your own fill station and you do not transport your filled cylinders on public streets/highways.

The standards for steel tanks for line or broadspread corrosion is condemnation for one or more pits greater than .020" deep - for isolated corrosion in 3AAs the pit depth is .040" - I don't have the numbers handy for other steel tanks.

 

[gitterdun]

You could always have the tank vis'd again by someone else.. I wish I would have done that when I purchased mine... I got lucky, but have learned my lesson...