Be Careful With Propane Tanks

[Onkel_Udo]

Yeah OP, you been skooled!

And never intended as such. I fully understand the fear and acknowledge it as real. The source is often ignorance (not stupidity) of were the danger lies.

 

[andy6026]

And never intended as such. I fully understand the fear and acknowledge it as real. The source is often ignorance (not stupidity) of were the danger lies.

I know. Your post was very good. I was just playing.

 

[Onkel_Udo]

I know. Your post was very good. I was just playing.

Well stop that! This is a serious forum about serious issues! Now back to combustion fairies...

 

[PeteNMA]

Regardless of the possibility or otherwise of making a perfectly stoichiometric mixture inside of any specific vehicle, (and regardless of claims of science around the air:fuel ratio), fuels still burn well away from perfect stoichiometric ratios, and there are also secondary concerns around personal well being if you accidentally get a lungful of compressed gas rather than the regular air which we are used to breathing.

It's not too hard to imagine scenarios whilst when driving a few seconds of blackout or even mild disorientation could lead to unfortunate results.

It should also be noted that there is a vast difference between a flammable liquid with a moderate vapour pressure (petrol) and a compressed, liquified gas. If the contents of your gas tank escape, they will not flash to vapour. If the contents of a propane tank escape, they will extremely rapidly turn to gas. As noted above the hazard is not limited to formation of a combustible air/fuel mixture, there are physiological effects to be wary of too.

Whilst I'm not sure that the OP's suggestion of a healthy fear is quite necessary, it never hurts to reinforce the fact that if you are transporting potentially dangerous materials it pays to treat them with respect. Your car manufacturer (Ford Pintos aside) will generally be paying careful attention to the placement of your gas tank to give it protection in case of an accident. They don't know what you are doing with your propane tanks.

 

[mattd2]

OK, by mass the stoichiometric mixture for Propane is about 15.5:1. Assuming a new Pathfinder, EPA interior volume is 157.8 cu ft at .08 # per cu ft. Standard propane tank holds 20 #'s. Assuming 0 ventilation, your mixture once the tank was empty would be 20:12. So there was risk while the tank was leaking if the Pathfinder was air tight. It is not and the risk was minute...almost laughable.

The thing is, you were also carrying around up to 117# of much more dangerous flamable liquid at the same time contained by plastic, synthetic rubber and with a ACTIVE electric pump and electric fuel level sender right there and the wiring connections to them IN THE TANK with the liquid.

Sure, crap happens and propane can leak. But I guarantee you miles driven, that car and the others like it driven by the idiots on the roads were 1000 times more likely to kill you. I would even bet the threat of that total weight 40# metal tank flying up and hitting you was higher than the leaking gas.

Good story, but please understand that the specificity of the mixture required to even create a flash-over is so specific that you need not worry unless you are in a confined space.

Edit: gas is not more volatile, it just has a very wide range of vapor pressure/mixture at which it is flamable...the volume is the main concern.

Why are you referring to the stoichiometric mixture? For an explosion it does not matter if the explosion burnt cleanly. Propane is explosive at a gas/air mixture of between 2.1-9.5%. It does not have to be specifically at the stioch. mixture. And above 9.5% you'd find yourself being asphyxiated.
So once approx 1/4 of a pound has been release in that Explorer you are at risk of an explosion with an adequate ignition source. The risk would be low if good ventilation is in place

 

[mattd2]

... Your car manufacturer (Ford Pintos aside) will generally be paying careful attention to the placement of your gas tank to give it protection in case of an accident...

You don't happen to be an engineer by chance... or at least taken a engineering ethics class in collage?

 

[PeteNMA]

Not quite. Unfortunately I'm an engineer by genetics, rather than by qualification

 

[mattd2]

Not quite. Unfortunately I'm an engineer by genetics, rather than by qualification

The pinto was an excellent case study... Unfortunately the University considered it to be such a good case study the used it in 3 out of 4 years of professional development / engineering ethics!
...Sorry for the Off Topic

 

[Paulfrank]

I just like the "almost laughable" part.

 

[seabrew8]

Now luckily all of the windows were at least partially open. However my instinct (rightly or not) was to not apply the brakes - since the spark from the break-light filament could possibly ignite the propane gas. Instead I used the hand break to slow down enough to make a left hand turn into an empty parking lot.

You should write some screen plays! You certainty could of hit the brakes with a small propane leak of 1-2min. Heck you could of even had a smoke!

 

[flars]

Check out this squad car dash cam video in nearby Rib Mountain, 7/31/2015.
http://www.wausaudailyherald.com/st...in-explosion-resulted-built-propane/30986785/

 

[Onkel_Udo]

I actually have to agree that the risk of asphyxiation is real. I also maintain that if the tank is unrestrained, the risk of being whacked on the back of the head with it is higher.

I have spent a lot of time on fuels safety. Without a controlled mixing of fuel and air, it is REALLY hard to ignite propane, methane or any of the other -ane's in a ventilated space. If allowed to pool in an enclosed space, the barrier layer easily meets the mixture requirements just like the vapors from gasoline.

So use caution but also use common sense,

 

[andy6026]

You should write some screen plays! You certainty could of hit the brakes with a small propane leak of 1-2min. Heck you could of even had a smoke!

(pssst, I actually did but I wasn't going to mention it as I thought it'd make me look like an idiot. Little did I know that this thread would accomplish that without inserting an image of me as the Marlboro Man).

 

[seabrew8]

By no means unsafe but your post was very dramatic. I worked on product tankers for a number of years - you can smell different levels of toxic and flammable fumes the majority of the time while on deck - we have to wear gas detectors. It probably wasn't leaking very long before you could smell it unless there's something wrong with your smell.

The O2 content would be the biggest issue - %21 oxygen content is safe. The propane if left to leak would reduce that number in an enclosed space.

 

[N3Bruce]

I remember a PSA when I was a kid that explained it perfectly. A coffee cup of gasoline properly vaporized can explode with the force of 2 sticks of dynamite. I strap my propane tanks to a tie point in the open bed of my pickup, in case you are wondering...

 

[MaxStout]

 

[Pantherjon]

^^^Very funny!..But, seriously, the burning question I have is: Did you get your propane tank back from the fire department?


Yes, pun intended...lol

 

[CajunChuck]

I think in the US it is not lawful to transport full tanks in an enclosed space.

HAHAHAHAAHAAH! Nice!

That being said, I now own a truck so yeah...