oxygen tank death

[rjack321]

No. 54 in-lbs * 12 is 648 in-lbs. 54 in-lbs / 12 ft-lbs/in-lbs is 4.2 ft lbs. I don't know where that chart came from that you referenced, but I put most screw pipe at 1 star torque, that is, I tighten it until I see one star. Cylinder valves are at 2 star torque, that is, put the cylinder in a air operated cylinder vice and tighten it until you see 2 stars. Removing valves takes many stars. I can't find an actual torque spec for cylinder valves aside from handle torque.

You're right my brain fart
4 ft/lbs is way under torqued but I can't find a source for installation either. Digging into this, I think the reason is because NGT/NPT requires a minimum number of engaged threads regardless of torque. And to not leak.

 

[TrimixToo]

You're right my brain fart
4 ft/lbs is way under torqued but I can't find a source for installation either. Digging into this, I think the reason is because NGT/NPT requires a minimum number of engaged threads regardless of torque. And to not leak.

Yup. ^^^

If I recall correctly, it's *x* turns past hand tight. I don't recall the value of *x*, and I am not looking it up tonight, but suffice it to say that I get out a Large Posterior Wrench(tm) when I need to valve or devalve a T bottle. I strap the tank to a trailer hitch on my SUV or motorhome because nothing else I have will hold it securely enough to prevent it from rotating unless I use a tree.

I entirely agree that nobody human will loosen one by hand, even if the tank is not pressurized.

To go off on a tangent, when you're done tightening the valve (and nursing the resulting hernia and rotator cuff tear), there is a specification for the minimum number of exposed threads on the valve. If it falls below the minimum, you order a valve with threads that are bit larger in diameter. I don't recall how many oversize valves are available, but they are used to compensate for tank thread wear.

 

[Wookie]

Yup. ^^^

If I recall correctly, it's *x* turns past hand tight. I don't recall the value of *x*, and I am not looking it up tonight, but suffice it to say that I get out a Large Posterior Wrench(tm) when I need to valve or devalve a T bottle. I strap the tank to a trailer hitch on my SUV or motorhome because nothing else I have will hold it securely enough to prevent it from rotating unless I use a tree.

I entirely agree that nobody human will loosen one by hand, even if the tank is not pressurized.

To go off on a tangent, when you're done tightening the valve (and nursing the resulting hernia and rotator cuff tear), there is a specification for the minimum number of exposed threads on the valve. If it falls below the minimum, you order a valve with threads that are bit larger in diameter. I don't recall how many oversize valves are available, but they are used to compensate for tank thread wear.

I have that wrench, and I put a 4 foot piece of 1 1/2" stainless pipe on it to save the rotator cuff.

 

[abnfrog]

they are usually put in and taken out hydraulically or with air guns

 

[PBcatfish]

It is absolutely common & standard practice in industry to spin tanks across a flat floor the way that was described. I've done it thousands of times. Pretty much everyone that handles industrial tanks above 122cf does it.

I don't see how the valve could have unscrewed. If it was even a little loose, the gas would have been hissing out big time.

The caps on the bigger industrial tanks can have a few different threads. There are at least 3 different pitches & at least 2 different diameters that I am aware of. It is (unfortunately) common for caps to get switched from the original tank where they fit well, to another tank where they fit very poorly or almost not at all.

I've seen a valve break off of a tank that was dropped 20 feet, but I've never know one to separate while being hand rolled. This is a very unusual event. The story was a bit scant on details of how exactly the valve separated. I would like to have more & better information on that detail. Simply saying that "corrosion is suspected" does not provide much real information.

 

[Bob DBF]

It is absolutely common & standard practice in industry to spin tanks across a flat floor the way that was described.

That is the method of moving cylenders by hand, except the cylender is supposed to be capped.


From OSHA, selected applicable regulations.

1926.350(a) Transporting, moving, and storing compressed gas cylinders.

1926.350(a)(1) Valve protection caps shall be in place and secured.


1926.350(a)(3) Cylinders shall be moved by tilting and rolling them on their bottom edges. They shall not be intentionally dropped, struck, or permitted to strike each other violently.

Simply saying that "corrosion is suspected" does not provide much real information.

From what I read they found corrosion around the valve, but I don't know whether the accident is still being investigated for the cause.


As I mentioned earlier, I'd like to know where that warehouse is, from the picture it is a poster child for poor practices.


Bob

 

[grf88]

The photo would suggest that it is not located in a first world country.

 

[Wookie]

The photo would suggest that it is not located in a first world country.

This is what I keep thinking. Anyone who has traveled elsewhere is not shocked by any of this.

OSHA and DOT are wonderful, but don't apply elsewhere.

 

[Miyaru]

The caps on my air and helium buffers can stay in place when connected, except for my oxygen buffer.
Never even thought about transporting one uncapped, the weight of the buffer is large enough to easily damage an unprotected valve.

 

[Bob DBF]

The photo would suggest that it is not located in a first world country.

This is what I keep thinking. Anyone who has traveled elsewhere is not shocked by any of this.

That was my thought earlier in the thread. It's interesting that the article does not mention where it happened, which is usually one of the first things mentioned in a report of an accident. I certainly can't think of a reason to leave it out.


Bob