FJ cruiser vs acetylene tank.. guess who won?
- Thread starter JohnR
- Start date
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wow, glad he's OK. Amazing -and great- he wasn't hurt worse. He should have hightailed it out of there as soon as he noticed the gas. The window bit was not good thinking, but that's easy to say after the fact.
Good reminder to be careful with flammable stuff all right.
Good reminder to be careful with flammable stuff all right.
- Thread starter
- #3
Doh, I was looking around and this was already posted in the cruiser forum. Acetylene isn't flammable. Hell, gasoline is flammable. Only under very specific conditions is it EXPLOSIVE. Gasoline deflagrates. Acetylene EXPLODES. If you look on youtube, a party balloon filled with acetylene will destroy the city-supplied trash cans, or launch a plastic chair 50' in the air.. I have always been anal with my tanks, 2-handed torque closing the valves and putting the caps back on.. now I know why.
pb4ugo
SILVER Star
Yeah, Always put the caps on when transporting gas cylinders.
And the darwin award goes to...
He is one lucky SOB.
He is one lucky SOB.
THIS is WHY I had to take the Transportation of Dangerous Good Cirtification class for my Refrigeration pre apprentice program.
1. Never ever transport a dangerous gas WITHOUT the collar attached
2. Never ever transport a gas without it secured to the wall when in transit
3. I cannot recall the minimum size of gas required, but you must have a UN placard of which gas is onboard the vehicle.
What he should NOT have done.
1. He SHOULD have never taken the car outside!! he should have left it in the garage and vacate the house.
2. Never flip any NON sealed switch. In fact, do not use any switch if possible. I do remember this from basic training. Sargent said "NEVER turn on a light switch if you smell gas.
Now he has a partial disability.
1. Never ever transport a dangerous gas WITHOUT the collar attached
2. Never ever transport a gas without it secured to the wall when in transit
3. I cannot recall the minimum size of gas required, but you must have a UN placard of which gas is onboard the vehicle.
What he should NOT have done.
1. He SHOULD have never taken the car outside!! he should have left it in the garage and vacate the house.
2. Never flip any NON sealed switch. In fact, do not use any switch if possible. I do remember this from basic training. Sargent said "NEVER turn on a light switch if you smell gas.
Now he has a partial disability.
And he should have pulled the tank out when he got home. Acetylene bottles should never be layed down BTW.
Holly F****ing S**t. How the hell did he survive. One lucky SoB.
FYI, acetylene (ethyne, C2H2) is a compressed flammable gas. A detonation is a explosion in which the combustion wave propagates at supersonic speed. This was just your everyday explosion, nothing more. And yes, gasoline can cause an explosion.
- Thread starter
- #9
IIRC, acetylene's wave propagation speed is pretty high. I did say gasoline CAN explode, but 99% of the time, it deflagrates. Acetylene's wave propagation speed is ~2500 m/s IIRC. I just looked it up, seems acetylene's explosive velocity is quite low compared to high explosives. TNT = 6,900m/s
PETN = 8,400m/s
RDX (C4) = 8750m/s
BUT, gasoline usually deflagrates. It can explode(detonate), but usually doesn't. Engines run on gasoline deflagrating, when it explodes(detonates), bad things happen (i.e. pinging, knocking, blown HG's, cracked pistons)... IIRC, the transition from deflagration to detonation happens at 1,000m/s... I can't remember how fast gasoline explodes at, but I remember it being UNDER 100m/s. And it's burning rate is far lower.. I agree though, he's one lucky SoB.
PETN = 8,400m/s
RDX (C4) = 8750m/s
BUT, gasoline usually deflagrates. It can explode(detonate), but usually doesn't. Engines run on gasoline deflagrating, when it explodes(detonates), bad things happen (i.e. pinging, knocking, blown HG's, cracked pistons)... IIRC, the transition from deflagration to detonation happens at 1,000m/s... I can't remember how fast gasoline explodes at, but I remember it being UNDER 100m/s. And it's burning rate is far lower.. I agree though, he's one lucky SoB.
You looked it up? That’s great…
Ignition of a gas-air mixture (within flammability limits) will usually result in a deflagration (flame propagation at subsonic speed away from the ignition site). When this happens in a vented enclosure or the open atmosphere, this deflagration continues until the lower flammability limit (LFL) is reached, at this point flame propagation terminates. This is a big fire ball like you see in Hollywood movies. When this happen in an unvented enclosure, the pressure developed in the enclosure is dependent on the extent of flame propagation and the temperature and composition of the burned gas. This is an explosion. When the unvented enclosure is not designed to withstand the pressure, it gets blown to shreds, like the FJ or a building or a…. And when it is designed to withstand the pressure, the pressure can perform work, like moving a piston (but it is still an explosion).
As I said in my previous post, a detonation is an explosion in which the combustion wave propagates at supersonic speed. Since flames in a deflagration propagate at speeds well below the speed of sound, the pressure increase within the unvented enclosure occurs virtually uniformly throughout the enclosure as the explosion evolves. However, the pressure rise during a detonation is highly non-uniform and occurs virtually instantaneously as the shock wave propagates. Think weapons not gasoline.
Whew… class is dismissed.
FYI: detonation in an engine cylinder has nothing to do the speed of the flame front and everything to do with when ignition starts and the crank timing. Same term, different meaning (you should look that one up too).
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- Thread starter
- #11
I stand corrected. It's been quite a while since I've taken classes,, but I just got schooled.
I understand now the differences between explosion and detonation.
I understand now the differences between explosion and detonation.