DescentBB

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NEVER ever pull out a flaming gas pump from your car. She was extremely lucky that it didnt shoot fire out all over her and burn her up like it did another fellow I heard about.

Rule of thumb #2: Never reach into/sit in your car while pumping gas. The static charge that builds up between your clothing and the seat can easily ignite gasoline, especially in the drier winter months. This is how most gas station-related fires start. There was recently a case of this in my area; the person was lucky enough to get away safely.

Rule of thumb #3, always ground yourself out before touching the gas pump by touching the side of the car well away from the gas cap.

....feelin' hot hot hot!......

heh. she even lights up a smoke..

Lucky, and not completely stupid. She reached carefully and stopped the pump, of course the better way would have been to go to the actual pump and push the big red button labled "PUMP STOP!". But at least she got away without any burns from the looks of it.

It is amazing that she did'nt blow anything up. I'd say she got very lucky that day.

We probably don't realise how flammable fuel can get, even though we all realise it 'burns fast when lit'

I spilt some fuel when disconnecting fuel lines on my car, so I moved away the car and decided to light it to see what gives.. Even though I was expecting fire when I threw the match on the small, already dried spot of spilt fuel, I didn't expect it to be so violent...

Remember: the fuel doesn't burn, the fumes do! If you forget this you might wonder why the flame is so violent...

Lobber wrote:Rule of thumb #3, always ground yourself out before touching the gas pump by touching the side of the car well away from the gas cap.

How does this work? The vehicle is on rubber tires and is not "grounded".

but every electrical system in the car is grounded to the chassis...work it out in your head

isn't dot VIERD????

woodchip wrote:

Lobber wrote:Rule of thumb #3, always ground yourself out before touching the gas pump by touching the side of the car well away from the gas cap.

How does this work? The vehicle is on rubber tires and is not "grounded".

1. The amount of the necessary static electrical charge that builds up on a person due to friction is very small (yet strong enough to spark ignition of the fumes escaping the fuel pump interface on the vehicle's gas cap)
2. A person becomes POSITIVELY charged due to friction between his/her clothing and interior car fabrics. The friction tears off millions of electrons leaving the person, who is usually wearing rubber soled shoes, and is therefore insulated, positively charged = lacking enough electrons to balance their overall proton charge.
3. Metal is composed of covalent bonded molecules that share a large proportion of electrons from both adjacent and distant atomic orbits. This easy flow of electrons across a large number of metal atoms is responsible for the conductivity of said metal, as well as the ease to which a body is rapidly neutralized when those electrons flow freely to someone who is positively charged.

Hence, the spark originates in the metal of the vehicle, and not the person, and thus the car doesn't need to be "Grounded" since its a one way transfer of electrical charge from the metal to the person.

Therefore, if you ground yourself out, by touching the metal, you equalize your own positive charge with enough electrons to replace was was lost during a static charge buildup.

Does that answer your question?

Your argumentation is incomplete, you did not address why this still works if the car is isolated on it's tyres.

The reason you can ground yourself to a car is that even though the car is isolated, it is big enough an object to render both your person and itself close to neutral when your body charge comes level with that of the car. You and the car will still remain slightly positive, but nowhere near enough to cause a spark or other effects.

Another thing to consider is, does car paint and finish conduct electricity? Because if it doesn't, there's no point in hugging your car to discharge yourself

Better is to touch the pump, I think. You should be quite discharged when you grab the metal handle while it still sits in the metal holder.

Tricord wrote:Your argumentation is incomplete, you did not address why this still works if the car is isolated on it's tyres.

The reason you can ground yourself to a car is that even though the car is isolated, it is big enough an object to render both your person and itself close to neutral when your body charge comes level with that of the car. You and the car will still remain slightly positive, but nowhere near enough to cause a spark or other effects.

I addressed that:

Lobber wrote:This easy flow of electrons across a large number of metal atoms is responsible for the conductivity of said metal, as well as the ease to which a body is rapidly neutralized when those electrons flow freely to someone who is positively charged.

"Large number of atoms" = quadrillions of atoms of metal in the car body.

Tricord wrote:Another thing to consider is, does car paint and finish conduct electricity? Because if it doesn't, there's no point in hugging your car to discharge yourself

Even if the paint acts as an insulator, its far too thin a layer to prevent electron tunneling.

Tricord wrote:Better is to touch the pump, I think. You should be quite discharged when you grab the metal handle while it still sits in the metal holder.

Good way to spark a fire.

Haha@last quote... that's why pump handles are rubber-coated here in the states.

During winter around here about half the time I get out of the car I get zapped when I close the door.

Bah, she was blonde. What do you expect?

A discharge does not imply a spark

A spark is a charge which ionizes air molecules in order to arc over to a conductor with a lower potential.

Anyway, we can look at this incident as statisticians as well. What is the chance of this actually happening like it did to that woman? It's virtually nihil, so the chance that it happens to you during your lifetime is very, very small. However, with six billions of humans on the planet, and like half of them standing at the pump at some point in their lives, the chance that someone gets it somewhere is very real.

snoopy wrote:Bah, she was blonde. What do you expect?

This is the most important safety advisory .

About the tires thing, you do realize that tires aren't all rubber, right? It has a wire mesh on the inside, and if its close enough to the surface, it can possibly act as a path to "ground".

Just move to Jersey, where there's actual gas station adendants.

i once saw someone set fumes on fire......first thing he did was go smash the "EMERGENCY STOP" button and call the fire dept. just in case anything else happend


and that woman is lucky as hell.....and ROTFLMAO!! @ her smoking in the car and trying to bash the nozzle on the ground to put the flame out on the tip of the nozzle

she may have grounded on the pump handle. It's metal too. Also, the car has a ground lead to a 12 volt battery.

Duper wrote:she may have grounded on the pump handle. It's metal too.

which is exactly what started the fire

Yes, that's why I touch the metal of the body of the vehicle being refueled several feet away from the gas port.

It's way TOOOOO dangerous *shudder* to pump gas here in Oregon, so they have trained professionals do that for us here. And for that, all the safer do I feel ... yea..

The point is not to "ground" yourself by touching the car, it's to make you be the same potential as the car. "Grounding" may be a bit mis-leading term in this instance. Sparks fly because you are at a different potential than the car. If you touch the car you simply set yourself at the same potential as the car. It doesn't have to be ground. The car may very well be charged, but by touching it you at least set yourself to be the same as it so there won't be any discharge when you touch it again.

That was definitely a static discharge that caused that fire. The buildup was most likely from all the messing with her sweater that she was doing. She's very lucky.

not to mention it's kinda hard NOT to touch your car before touching the pump handle... since you have to open the fuel door to unscrew the cap.

I suppose you can do both at the same time, but most ppl work the fuel cover door before they ever touch the nozzle where I work.

Good stuff. I saw this on 20/20 or sixty minutes years ago. Back then they were still learning about it. I remember they said it was three times as likely to happen to women than men, because women tend to get back in their car during a refill.

This video is even 'sparking' a spam campaign and a website from the Petroleum Equipment Institute HERE. Even has a pic of the girl from this video.

Their rules of thumb:
1 - Turn off Engine
2 - Don't smoke
3 - Never re-enter your vehicle

I couldn't find anything about grounding yourself on your vehicle, but I do remember that suggestion from the TV show.

These incidents happen after refueling, this is why (according to the website) they do not use a static discharger like they do on aircrafts, which are discharged before refueling.

Buef wrote:These incidents happen after refueling, this is why (according to the website) they do not use a static discharger like they do on aircrafts, which are discharged before refueling.

that event occured DURING fueling.

they use static grounding lines on airliners and other aircraft, because the JP-4 "Kerosene" that they burn in turbine powered engines is much much more volitile than unleaded gasoline. one spark could send a couple ten thousand gallons of fuel into a fireball the size of a football field. and if that fire makes its way into the fuel pumping system for the airport, a very ugly explosion could be the possible result. an explosion of this type would be powerful enough to level or severly damage buildings for about a mile or so.

the AVGAS-100 and AVGAS-120 grade fuels used in piston powered aircraft engines are like regular gasoline for cars and vehicles, but they are enriched and have a much higher octane and higher burn temp.

AceCombat wrote:...because the JP-4 "Kerosene" that they burn in turbine powered engines is much much more volitile than unleaded gasoline.

I donâ??t think you are correct about that Ace. Gasoline is much more volatile than JP-4. Flash point (FP), or the temperature that a liquid vaporizes is an indirect measure of flammability. A liquid isnâ??t considered flammable unless itâ??s flash point is 4 deg C or lower. Ignition temperature (IT) is the temp at which a vaporized liquid will ignite and the energy density (ED) is the amount of energy per unit volume.

The flash point of gasoline is -40 deg C, the IT is 232 deg. C, and the ED is 45 MJ/kg.

The FP of JP-4 is -18 deg. C, the IT of JP-4 is 272 deg. C, and the ED of JP-4 is 42.8 MJ/kg.

So you see, gasoline not only vaporizes at a lower temp, it also ignites at a lower temp and has a higher energy density than JP-4.

Itâ??s just plane (pun intended) physics. Gasoline is more volatile that JP-4.

I would say, however, that the increased quantities involved, and people likely to be affected calls for much higher safety standards on airplanes than with regular gasoline.

snoopy wrote:I would say, however, that the increased quantities involved, and people likely to be affected calls for much higher safety standards on airplanes than with regular gasoline.

No question.

i guess i need to pay a few visits to some publishers who wrote a couple aviation science books. i stand corrected.

Getting back into the car may have not had much to do with it. I'd wager that all the tugging on her sweater built up the charge. Sweaters are major ESD generators.

Buef wrote:Good stuff. I saw this on 20/20 or sixty minutes years ago. Back then they were still learning about it. I remember they said it was three times as likely to happen to women than men, because women tend to get back in their car during a refill.

This video is even 'sparking' a spam campaign and a website from the Petroleum Equipment Institute HERE. Even has a pic of the girl from this video.

Their rules of thumb:
1 - Turn off Engine
2 - Don't smoke
3 - Never re-enter your vehicle

I couldn't find anything about grounding yourself on your vehicle, but I do remember that suggestion from the TV show.

watch again how much she "fusses" with the sweater. I wonder if it was clinging to her.

AceCombat wrote:i guess i need to pay a few visits to some publishers who wrote a couple aviation science books. i stand corrected.

Yeah, according to Hess' Material Safety sheets, gasoline is class 1A flammable and Jet fuel is 1B - either way it's "use with extreme caution" sort of stuff.