What happens when you use the wrong sealing materials on your tank

[breg]

I posted this on MCB, it needs to be shared

Tank failure thread on MCB

[my automag]

Thank you for sharing this, very important...

I for sure think twice and check twice when using the Shoebox on my HPA tanks, since I fill them myself now, I would not want this to happen somehow with second hand gear.

D.K.

[zondo]

Did the guy say what he used to seal the gauge??

Wow! judging by the hole in the wall, your guy is lucky to have a knot on his forehead!!

[BiNumber3]

He's guessing the owner of the tank used a petroleum based sealant or something on the gauge threads, or any of the threads for that matter.... i'd imagine the tech could have a fracture, pinpoint high velocity impact hopefully it's just a bump though

[GEE TEE]

Very nasty accident

[Ando]

"Looks" like liquid tap sealant.

[Beemer]

I posted this on MCB, it needs to be shared

Tank failure thread on MCB

The reg seperated from the tank moments OR minutes AFTER a fill. Why?

The tank went one way the reg another correct?

What do we know? What is the history of the TANK and REG. How do you know it wasnt a thread or torque failure? If it wasn't torqued to spec it could have spun it self off. Air bearing effect. Especially if the THREADS were damaged from a Reg removal[over torqued with loctite] for a hydro.

Thanks for the heads up post. The best we can do is to be informed and educated.

[athomas]

I am posting the same thing here as I posted on MCB.

A proper slow fill reduces heat produced. If there is no heat, then there is no ignition of petroleum contaminants.

I would like to see the tank threads. From the explanation, I am guessing that the ignition of petroleum contaminants caused expansion of the tank contents, which expanded the neck of the tank itself so that the threads between the regulator and tank were no longer in contact. The heat from the fill may not have produced a hot enough value to ignite the fuel, but may have gotten close. A bump on the regulator at the counter may have caused the extra heat at the point of contact to reach the ignition level and start combustion.

The purge holes in the threads are not designed to relieve this kind of pressure effect. They are only designed to relieve pressure is the tank starts to unscrew from the regulator, which is a slower event.

[my automag]

I am posting the same thing here as I posted on MCB.

A proper slow fill reduces heat produced. If there is no heat, then there is no ignition of petroleum contaminants.

---( so does this mean that the heat build up inside the tank gets to a point where it is intense enough to cause ignition and or combustion, but not pressure rise? )

I would like to see the tank threads. From the explanation, I am guessing that the ignition of petroleum contaminants caused expansion of the tank contents, which expanded the neck of the tank itself so that the threads between the regulator and tank were no longer in contact. The heat from the fill may not have produced a hot enough value to ignite the fuel, but may have gotten close.

---( I was thinking that by this point there would be some kind of pressure rise in order for the tank to be forced to expand...more than under normal conditions. )

A bump on the regulator at the counter may have caused the extra heat at the point of contact to reach the ignition level and start combustion.

The purge holes in the threads are not designed to relieve this kind of pressure effect. They are only designed to relieve pressure if the tank starts to unscrew from the regulator, which is a slower event.

---( this to me in a weary way says..." there goes the idea of SAFETY burst discs really being fail proof. )

There should be more care take flash filling especially...no thank you.

D.K.

[Ando]

Did i read it wrong? The reg popped off? I thought it was the whole tank that went flying

[kcombs9]

---( so does this mean that the heat build up inside the tank gets to a point where it is intense enough to cause ignition and or combustion, but not pressure rise? )

when you fill your tank fast the pressure wont rise over time from the heat of the fill its already at a higher pressure, unless the tank continues to have heat applied to it. if you don't use your tank as it cools you can check your gauge you will actually have less pressure in your tank then right after it was filled.

[athomas]

---( so does this mean that the heat build up inside the tank gets to a point where it is intense enough to cause ignition and or combustion, but not pressure rise? )

The heat by itself will cause a slight pressure increase, but not enough to exceed even the burst disk. If there is ignition, it becomes an explosion, where there is significant heat and a rapid increase in pressure. The fuel source may not ignite at that temperature in normal situations but in high pressure, the required ignition temperature is reduced. That is why diesel engines work so well without a spark plug, but diesel fuel doesn't explode when you light it with a match.

---( I was thinking that by this point there would be some kind of pressure rise in order for the tank to be forced to expand...more than under normal conditions. )

See above. The expansion would be due to the increase in pressure due to the explosion.

---( this to me in a weary way says..." there goes the idea of SAFETY burst discs really being fail proof. )

Safety burst disks are designed to prevent overfilling or gradual increases in pressure due to an external heat source. They will burst and relieve the pressure. An explosion happens too fast and there is no way to exhaust that amount of pressure out through a small hole as fast as the explosion happens.


They were actually lucky that the regulator blew off. If the pressure hadn't been released, the tank may have exploded into shrapnel. I would say the tank itself must have been well constructed.