Don't Want To Explode

[Mc Taco]

Those are pretty cool. The set up that I'm planning might not work with that style holder. I'll post some pics this weekend if I get to it. I'll just need to lift the can up and over the bed rail. Want the weight as far forward as possible. I want to use the siphon to avoid spilling fuel. Not just to protect the environment, but because I'm cheap and hate to lose even a drop!

 

[pray4surf]

Very interesting thread :lurk:

Those are pretty cool. The set up that I'm planning might not work with that style holder. I'll post some pics this weekend if I get to it. I'll just need to lift the can up and over the bed rail. Want the weight as far forward as possible. I want to use the siphon to avoid spilling fuel. Not just to protect the environment, but because I'm cheap and hate to lose even a drop!

Your describing kind of what I've been thinking about re carrying spare gas. I had been planning on carrying 1-2 20L cans (metal) of fuel forward of the wheelwells, preferably on the drivers side. I don't know if I'm going to be able to get them in/out of that location with my RTT on and the bed packed for a trip. Even with the bed empty wrestling a full can into place could be interesting...

I too spent a lot of time handling JP-4 around C-141's. The aircraft are grounded at all times, specially when fueling/defueling. What if the fuel cans are 'properly' grounded while still in the truck (using a grounding cable - jumper cables could do)? And if so, what could I ground to at a gas station?

Edit 12/10/09: I've noticed at the base of the gas pumps at the Chevron I frequent, a 'Grounding point' and labeled as such.

 

[trump]

I too spent a lot of time handling JP-4 around C-141's. The aircraft are grounded at all times, specially when fueling/defueling. What if the fuel cans are 'properly' grounded while still in the truck (using a grounding cable - jumper cables could do)? And if so, what could I ground to at a gas station?

I was thinking that might be an option too. A simple metal cable just like on the fuel truck one end clipped to the handle of the can and the other to metal fittings on the pumps hose maybe. Really it's not that difficult from me to get my cans on the ground, so I'll probably never give it a shot... nor would I really want to test bunny it.

 

[saburai]

Please educate me as to the differences between filling metal and filling the plastic OEM gas tank in my XJ.

The Jerry cans are in metal carriers, held down with metal straps bolted to a metal bumper on a metal truck, sitting on rubber tires as is the rest of the truck.

How is it safe to fill the truck but not the cans?

For that matter, why is it safe to transfer from the cans to the truck?

Many thanks...

 

[UK4X4]

Locally we have a system
where you beep your horn
and an Indian runs out to your truck
you wind down your window just a tad so that he can hear
Instruct him on what to fill and how much
Then wind the window back up to stop the cool interior disappearing
Engine running

Then repeat when he comes back with the bill

Safety wise, locally they seem to consider their Indian expats as disposable

You can ground plastic - hence putting the plastic can on the ground

A copper grounding strap - can to the vehicle body should be sufficient

Note the strap should be in place before filling.

and paint is an insulator

 

[JamesDowning]

I beleive the key is actually making sure the can and the nozzle have the same voltage potential. The reason placing the can on the ground is so important, is that you ground the can by touching it. When you touch the can and the metal of the nozzle with separate hands, you bring them to the same voltage potential. (notice that all fuel filler nozzles have some sort of exposed metal that you should touch before filling)

This is why they tell you to ground yourself to your vehicle (by opening your gas can cover) before fueling your normal gas tank.

Ground is all relative, and as long as the fuel can and the nozzle are grounded together (through your body) they cannot create an arc between them. Again, it's not about grounding to the truck body, it's about grounding the fuel nozzle and the fuel fill receptacle together.

 

[charlieaarons]

So from this discussion I gather that filling metal cans on the roof of my pretty-much-all-plastic camper with diesel fuel, with a metal nozzle touching the can, should be OK?

Charlie

 

[CoastalDefender]

So from this discussion I gather that filling metal cans on the roof of my pretty-much-all-plastic camper with diesel fuel, with a metal nozzle touching the can, should be OK?

Charlie

Some of us find it risky, some of us do not.

 

[ntsqd]

FWIW diesel is much harder to ignite than gasoline. At work we were doing some rather odd stuff and had occasion to test the dielectric strength of diesel. To do this a High Potential ("Hi-Pot") test unit is used. Basically it generates up to a 10kV+ potential (with no significant current, I think the unit that we rented could go to 100kV) and measures what the electrical resistance is of what ever you're testing.

I can tell you that the dielectric strength of diesel is impressively high. The spark would rather go through several inches of air than through a 1/8" of diesel. At no time during that spark jumping over and around the diesel did it ignite or even hint that it might try to.

We have actually made a diesel fueled, spark ignited engine run and produce usable power. It's not practical to do outside of the lab because of the steps it takes to over come diesel's general resistance to spark ignition.

I'm not saying that it won't spark ignite because we did it, but it sure isn't easy inside of an engine's cylinder. I'm at a bit of a loss as to how you'd accidentally create those conditions outside of an engine. I'm sure that a sufficiently talented fool could do it, but a prudent person being reasonably safe is very likely to have trouble doing so.

 

[Cabrito]

I consider myself educated after this thread.

I have never seen anything like in those videos happen in person.

I have always taken my gas cans and placed them on the ground when filling them. It has always just seemed like the right thing to do. I guess my subconscious common sense works sometimes.


Nice discussion. Thanks guys!

 

[charlieaarons]

This thread has really gotten my mental gears turning the last 3 days.
I was a physics major in college and think about it very frequently even in my dotage (I turn 60 in 2 weeks).
It seems to me there is no fundamental difference between filling metal jerrycans on the roof and a metal fuel tank on the vehicle, both are insulated from the ground by the tires but are grounded to the nozzle if it is touching the filler pipe. Sure, the metal tank is grounded to the frame but I don't touch the frame when filling.
To me the real problem is plastic tanks. Plastic can't ground to the nozzle. The car mfgs have switched to high density polyethylene tanks for many/most applications. Can someone confirm:
1) Is the filler pipe metal?
2) If so, is there a thin metal strip running down inside the tank all the way to the bottom?
3) They have to have done something to 100% eliminate the possibility of static-induced fires filling plastic gasoline tanks.

Having concluded this and knowing that the flash point of #1 diesel is >100 F. (much higher than winter temps) and #2 >126 F., I have no worries filling my metal cans with diesel with the nozzle touching the can, even on the plastic roof of the vehicle.

Charlie

 

[R_Lefebvre]

I'm on the skeptical side of this too. I don't doubt the truthfulness of those videos, but there must be something else to this.

To answer some of Charlies questions: The filler pipe used to be metal, as did the fuel tanks. Around about the 90's, they started making the fill pipe and the fuel tanks out of plastic because it was cheaper and corrosion resistant. I don't know if there was a grounding strap in the filler pipe, but I don't recall ever seeing one, and I worked for a company that made them (was not directly my responsibility).

Round about 2004ish, they started moving away from plastic tanks due to emissions laws. Turns out that vehicles burn so clean now, they emitted more unburnt hydrocarbon right through the plastic gas tank walls than out the tailpipe. Metal is much more impervious to fuel vapor.

As for the act of opening the gas filler door grounding you, well, most cars these days have a plastic gas filler door. And I'd love to know how or why placing a plastic gas can onto a non-conductive concrete surface could possible ground the can?

Furthermore, and this is a big question... why would it not be safe to fill a plastic gas container in the back of a pickup truck, but it IS safe to fill my motorcycle which has a plastic tank bolted to a metal frame?

I think there's WAY more to this than the simple bullet-point safety tips which are commonly stated.

 

[GDmovingtoAlaska]

I am in the military and while stationed at an Air Force base in San Antonio, TX in 2002, an individual was fueling a plastic can in the back of his pickup truck. It ignited and he was severely burned. They had the surveillance camera video on the news. I will never fill a container until I have placed it on the ground no matter if it's plastic or metal. Just my .02

gd

 

[ntsqd]

Maybe the place to start is to ask what generates the static?

Is it due to the fuel flowing into whatever container?

Is it due to the fuel being poured or consumed out of the container prior to the re-filling?

Is it due to air flowing about the container while the vehicle was moving prior to the filling?

Is it in the filling hose?

Once the location of the charge is known, then the proper steps to short it to ground or otherwise bleed it off can be taken and it won't be some mysterious force best only dealt with via hocus-pocus.

 

[R_Lefebvre]

I agree. I'm not doubting that it happens. I've seen the videos, I believe them. But I'd like to know why. Why is it ok to fill the plastic tank on my motorcycle, but it's not ok to fill a plastic tank on my truck? Maybe it's the type of plastic?

Maybe fires sometimes start even by filling according to all the rules, but when that happens it's labelled as a "freak accident" and isn't circulated. But when the same freak accident happens and one of these "rules" is broken, it becomes an example.

I dunno. I see warnings, but no science.

There was one video posted here where the guy is just filling his car. It was stated he was using a cell phone, but I can't see it in the video. I dunno. Also Mythbusters tried to start a fire with a cell phone, and couldn't.

I know a lot of gasoline combustion, and can state it only burns in a very narrow window of fuel vapor concentration. Between about 18:1 and 8:1. Trust me, there is no way that 18:1 ratio occurs anywhere near your head while you're talking on a cell phone. Certainly if it did occur, you'd notice because that much fuel in the air would probably knock you off your feet from the smell. I don't even know how you would achieve it close to the pump handle itself. I could only see it happening RIGHT at the mouth of the fuel container. Deep inside, too rich. Any distance away, too lean. So even if a cell phone could ignite it, you'd have to be holding your phone right at the mouth of the pump? Maybe cell phones are the scapegoat for all the unexplained fires that occur when the rules are followed?

The other one with the woman filling her car, that's very easy to see what happened. She got in and out of her car and the first thing she touched was the pump handle. Anybody who's driven a Ford especially knows about the static charge they get.

<shrug> Like I said, I'm not disbelieving the professionals, but I'd love to know the science behind it if it is as well understood as suggested.