Yeah, leaving an acetylene tank in a closed vehicle is not so bright. Vehicles are way too airtight for that, even a leak in a garage would dissipate some.
But acetylene is no joke. It has a flammability range of 2.5-100%Basically, its NEVER too rich and ALMOST NEVER too lean to burn. For a comparison, propane has a range of 2.2 to 9.9%. That's it, a little over a 7% range. And look at all the problems we have with propane.
Moral of the story, if you think you've got an acetylene leak that's filled a closed space,
get the hell out. And then call 911. Trying to vent it yourself may prove fatal, because introducing air doesn't help until you're below 2.5%. And you don't need an open flame, static electricity is enough to set it off.
I have always had this fear.
Put the empty tank in the Jeep.
Drive to the local AirGas.
Exchange tanks.
What if you are in an accident on the way back home?
Acetylene is stored in the tank in a solution with acetone. Unless the tank is ruptured in the accident, you're ok. If the tank is ruptured, it will react just like any tank under pressure, becoming a rocket. In that sense, its not really any more dangerous than an oxygen tank, the gaseous acetylene left behind your rocket would be flammable, but it would be in the open air at that point, because it would have rapidly left your car. The biggest issue with acetylene is in its gaseous form, so you'd need a slow leak.
