Regulator's pressure meter of 15 ltr. LP gas cylinder showing RED!!!

Here in Australia (and I assume elsewhere) all LPG cylinders are fitted with a pressure relief valve to prevent tanks bursting. They can often be seen venting in house fires.

Mike.

i went to a .50BMG shoot here in Colorado s few years back, and the local fire department that sponsored the event had several hundred expired propane tanks out on the range as targets. the trick to setting them off was to hit them once with a bullet, then follow up with a tracer to ignite the gas. they even had a 1000 gallon tank out at 1000 yards which provided a good sized fountain of flame when it got set off... these tanks were all about 10% full, and didn't go off spectacularly like in the movies. if you puncured the tank, and then put a tracer through the escaping gas, it would ignite because it had a chance to mix with oxygen, but actually hitting the tank with a tracer usually wouldn't set it off because there was no oxygen inside the cylinder.

on the last afternoon of the shoot, the fire department and sheriff's department placed charges of tannerite and dynamite out on the range. they put an office trailer out at a mile with 10 sticks of dynamite in one of the windows, and painted the window fluorescent orange. when the range went hot, it was about 10 seconds before somebody hit the window, and the office trailer disappeared...

unclejed613 said:

but actually hitting the tank with a tracer usually wouldn't set it off because there was no oxygen inside the cylinder.

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I once saw what at first sight was a disaster about to happen.
A welder was welding a tapping pipe/flange onto a 24 inch pipe which contained methane at about 42 Bar (600psi).
When I queried this with one of the safety guys, he had no problem with it.
The pipe was so thick there was no possibility of the welder burning through it, and because the methane was quite pure with no oxygen, there was no chance of an internal explosion.

JimB

somewhere on youtube is a video about the difficulty the RAF had shooting down zeppelins in WWI over London. they tried tracer bullets, they tried incendiary bullets, nothing worked reliably because the tracers and incendiaries were passing through pure hydrogen. what they finally hit on that did work was alternating ball ammo with incendiary bullets. the ball ammo would poke holes in the gas bag, and suck in some oxygen as it passed through, and the incendiary bullet, passing through near the first hole would ignite the mixed gases, or ignite hydrogen that leaked out and mixed with air.

by the way, one thing that's done with tanks of gases when they are empty in the military (and i'm fairly sure this only works in english speaking countries) is to mark the tank "M T". i'm not joking, they actually do this.

unclejed613 said:

by the way, one thing that's done with tanks of gases when they are empty in the military (and i'm fairly sure this only works in english speaking countries) is to mark the tank "M T". i'm not joking, they actually do this.

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Yes that happens in the UK also.

JimB