Brave Man

[BobDavid]

Anybody ever see the movie "Wages of Fear?"

[Patricia Sheley]

And I worry about dropping just one cylinder too hard...and he'd actually smiling, or maybe that's at seeing your reaction. These are the fun ones. Why we walk around with our cameras embedded.

[Rob C]

Come to Spain and you see butano bottles stacked everywhere, even in direct summer sunshine. Maybe it's all calculated within the loading pressure parameters...

Some years ago, I think it was in France, a truck overturned and all those cylinders blew up a campsite and everyone in it. It's a constant danger in every kitchen, and was in our own, until I had my first heart event and could no longer carry the damned things from the car park, down the path and then up steps into the house. Shortly after, we went totally electric, and Sunday's storm brought a power cut twice as I tried to make paella... if the left one doesn't get you then the right one will.

Rob

[Eric Myrvaagnes]

I think he just put out his cigarette, which is now under his foot.

[Slobodan Blagojevic]

Pardon my devil's advocate hat, but with all those highway sniper shootings, or a good old road rage with a gun, one (devil?) can't help thinking of what would happen if a bullet is to pierce one bottle in that truck?

[Rob C]

Pardon my devil's advocate hat, but with all those highway sniper shootings, or a good old road rage with a gun, one (devil?) can't help thinking of what would happen if a bullet is to pierce one bottle in that truck?

I saw a flm on tv where they were trying to shoot a car's petrol tank to see if it works like in the movies: they shot several shots right through one, and nothing happened other than a leak. Whether liquid petroleum is more volatile I don't know. Don't want to be around to find out!

Rob

[degrub]

Come to Spain and you see butano bottles stacked everywhere, even in direct summer sunshine. Maybe it's all calculated within the loading pressure parameters...

Some years ago, I think it was in France, a truck overturned and all those cylinders blew up a campsite and everyone in it. It's a constant danger in every kitchen, and was in our own, until I had my first heart event and could no longer carry the damned things from the car park, down the path and then up steps into the house. Shortly after, we went totally electric, and Sunday's storm brought a power cut twice as I tried to make paella... if the left one doesn't get you then the right one will.

Rob

Rob,

The France accident (and several others over the years) was a result of overfilling the LPG tanker (not bottles). When liquefied gasses do not have sufficient vapour space to expand from solar heating of the tank, the tank can rupture. The cold liquid and vapour mixture flowed down into the campground where it was ignited, killing many in the flash fire.

Frank

[Rob C]

Rob,

The France accident (and several others over the years) was a result of overfilling the LPG tanker (not bottles). When liquefied gasses do not have sufficient vapour space to expand from solar heating of the tank, the tank can rupture. The cold liquid and vapour mixture flowed down into the campground where it was ignited, killing many in the flash fire.

Frank

Well that's interesting; my memory of it had always been fixated on bottles. It's been years now since going non-butano, but those heavy, reddish/orange bottles used to have the figures 13,5 (or thereabouts) written on the sides; I don't know if it was a measure of pressure or of weight, but they certainly felt very heavy indeed well before I had the heart glitches, so perhaps the reference was to pressure.

Rob

[N80]

On Myth Busters they repeatedly shot LP tanks and could not make them explode or even catch fire. I think they even tried tracers and no go.

My dad was a revenuer back in the day (1960's). When they raided a moonshine still they would destroy everything. Many of the big operations used those long torpedo shaped canisters. The revenuers would shoot the bottom of the tank with a rifle. They would not explode or ignite but the internal pressure would shoot it off like a rocket.

[Bob_B]

Pardon my devil's advocate hat, but with all those highway sniper shootings, or a good old road rage with a gun, one (devil?) can't help thinking of what would happen if a bullet is to pierce one bottle in that truck?

Oddly enough, this was exactly my thought too.

[Bruce Cox]

When the backhoe operator comes running across the highway towards you screaming, the proper procedure is to dive into the stock tank.  All else is bootless if the pipeline is big enough.

[N80]

B.L.E.V.E.

https://youtu.be/K-tUQTw_Vtk

[degrub]

Any LPG rail car/truck involved in a fire necessitates about a 1 mile (1.6 km) stand off distance because of the rocketing of the split container. 
We also deal in self-reactive chemicals - 1 km is the minimum stand off distance for rail or truck volumes.
Been there when it happened.

former HAZMAT responder.
Frank

[degrub]

Oddly enough, this was exactly my thought too.

Not a lot actually. Not a lot different from opening the primary valve on the top of the container. If there is an ignition source, then a small jet. Where it gets interesting is if the jet fire hits other cylinders. The heat up can fail the fusible plug or rupture (if no fusible plug  - ie a LPG BBQ tank) the container. There have been a few dramatic fires at  cylinder storage/refilling facilities due to this domino effect and the inability to push a lot of water onto the impacted cylinders.

A truck with cylinders on the back going down the highway would likely not be a real issue as the jet would be outward facing. Driver might not even notice.

[Otto Phocus]

Not as dangerous as one might think

Propane does not burn.  Propane mixed with air burns.  Specifically, at normal atmospheric pressure, the combustion range is 2.15% propane (97.85% Air) to 9.6% propane (90.4% air) will support combustion.  Outside of those ranges and combustion won't occur.

In addition to the proper mixture of Propane and air, you need an external ignition source (spark or flame).  Without an external ignition source, the proper Propane/air mixture would need to be heated to about 1,000 degrees F (depending on the condition of the air) in order to spontaneously burn. 

So to set the truck on fire one needs to make the proper mixture of propane and air (one reason why these tanks are not enclosed) AND provide an external ignition source.  About the only thing you would have working for you is that propane is heaver than air.  Also it would be difficult for the combustion to propagate to other tanks.  Your standard Propane tank will burst (if you want to impress people the proper term is BLEVE - Boiling Liquid Expanding Vapor Explosion) at about 1,000 psi.  Well past the point when the safety valve or even the main valve would rupture.  It is almost like some engineers specifically designed propane tanks to be safe or something. 

So, to the chagrin of amateur terrorists, it is difficult to make a tank of propane do anything but burst.  This one of the reasons why propane is such a useful fuel... it is pretty safe. This is why propane tanks are readily available to the public... they are pretty safe.

To the OP:  Awesome movie reference.  One of my favourites.   

In EOD school we tried making IIDs out of propane tanks and, like every class before us, found out that there are much easier ways to make an IID. 

[Slobodan Blagojevic]

And yet... we frequently hear a whole building is brought down by a gas explosion in many cities around the world, including NY. Equipment malfunctioning is often cited as the cause.

[degrub]

And yet... we frequently hear a whole building is brought down by a gas explosion in many cities around the world, including NY. Equipment malfunctioning is often cited as the cause.

Yes, quite simply there is methane mixed with air, sometimes in a still environment so that it diffuses well and comes to a consistent composition AND it is contained by rigid walls and roof. If the composition reaches to near the ideal for combustion (stoichiometric), then the maximum rate of energy release can occur resulting in the highest pressure multiplier. When a fuel burns in air it wants to expand in volume by about 8x. When it cannot - ie when it is enclosed by the walls and roof of a building - the building interior pressure will rise resulting in windows blown out at first.  If that is not enough relief area, then the walls and possibly the roof will fail outwards. It doesn't hurt that most buildings are designed for only external wind pressure (<0.1 lbs-force per square inch area) and even less internal pressure. If the walls and roof could resist the pressure rise, the peak internal pressure would be near 7 atmospheres gauge - a little over 100 lbs-force per square inch area net. No wall short of steel or reinforced concrete can resist that.

That is why any flammable gas that leaks inside a building can produce a significant explosion, particularly if it is in the basement where the earth resists on 5 of the 6 sides.

Frank

[RSL]

Back in the forties there was a gas explosion in Birmingham, Michigan that obliterated a house and killed the two people in it.  The town practically shut down for an extended period while all the gas lines were replaced. The house that was blown up didn't even have gas. The gas line just ran close to the side of it.