Safe to store in the garage?

[halocline]

So let me get this straight; you're concerned about storing a steel tank wet enough on the inside to have actual water pooling inside, or possibly in a corrosive enough environment so that the exterior of the tank, which BTW is designed to be used-guess where- underwater- is at risk, and you actually think standing it up makes a difference?

 

[tadawson]

You don't need a pool inside - moisture is heavier than air, and well tend to head for the low end. And externally, ground contact with god knows what can cause issues as well.

It *DOES* make a difference . . . but likely, you won't care . . . And even Luxfer cautions against damp concrete, which will trigger the exact issue I discuss . . .

- Tim

 

[halocline]

My point is that if the tank is wet enough on the inside or on a wet enough surface to actually cause damage, that's a serious problem for which simply standing it up is not a solution. Just store the tank with dry air inside and on/in a dry environment.

 

[tadawson]

I think you grossly misestimate how little moisture it takes to cause problems over enough time . . . just because you can't see it, doesn't mean it isn't there . . .

- Tim

 

[halocline]

I'm not "misestimating" anything. It's really simple; wet air inside the tank will cause corrosion, dry air won't. I realize nobody intentionally gets a wet fill. But if you store a tank with a wet fill, you're going to have corrosion regardless of the orientation of the tank, and a corrosion pit of "X" depth or size will cause the tank to fail inspection regardless of it's location in the tank. So, you have to take care to make sure your tank has nice dry air in it before putting it up for storage.

The exterior is even simpler; just don't store your tank where it's wet enough to damage the finish, period. (I don't know how wet that would be) If you're in such a questionable location that you think it's "better" for the tank that only the bottom is contacting the surface, you're in the wrong place.

 

[tadawson]

I and a corrosion pit of "X" depth or size will cause the tank to fail inspection regardless of it's location in the tank.

I take exception to that statement . . . corrosion in the base will be a far smaller percentage of overall thickness, and most mfgs. give a far higher tolerance for pits there than on the sidewalls. Now whether the average vis monkey will know or care about that is another thing altogether . . .

And you aren't actually trying to claim that the bottom of a tank, with it's much greater wall thickness than the sides is the same strength are you? If not, the discussion is over - you just agreed with me . . . The issue is whether anyone in the "real world" cares . . .

- Tim

 

[halocline]

Do you have some evidence that the depth or size of corrosion pits that is considered acceptable varies due to location? Here's the Luxfer language on it for exterior and interior:

CONDEMN all cylinders with one or more external corrosion pits over 0.060
inch (1.53 mm) deep in the sidewall,crown,and/or base.

CONDEMN all cylinders with any interior sidewall,crown,or base isolated pit
estimated to be over 0.060 inch (1.53 mm) deep.

So, they don't differentiate between pitting in the sidewall and in the base. I have not taken the PSI course, but I strongly suspect that their guidelines don't either. If you can find anything that contradicts this, knock yourself out.

We could keep arguing about this as long as you want, you're never going to convince me that storing a cylinder upright or on it's side makes a difference; it's just another bit of dive shop lore I suppose. What makes a difference is the quality of air in the cylinder and the environmental conditions in which it is stored.