While on a trip, my friend and I stopped at a gas station to fill up the tank. While the attendant was pumping the gas, i was getting out of the car. My friend yelled at me not to shut the car door. Apparently she heard news reports about cars catching on fire while the gas is pumping because the force of the shutting car door rocks the car and can cause static sparks in the gas tank or in the contact points of the gas nozzle and car frame. Is any of this even possible?

I've heard this one too. In fact, it's why I joined this forum. The version I had heard wasn't as detailed as yours, Chibi. I had heard is that something about opening or closing car doors while pumping gas could generate an explosive static discharge. Seems pretty unlikely to me, but I suppose that's what this show is all about!
On a similar note, you are warned not to keep your car running, or even have your keys in the ignition while pumping. I've never risked it, but is there a danger of explosion if you fill up with the car on? This has Mythbusters written all over it: cars, everyday situation, common wisdom versus scientific method, and, of course, a possible explosion!

Mythbusters have already tested this. See the episode "cell phone destroys gas station." They investigate static discharges in addition to cell phones.

In my experience it is not the act of opening and closing a car door that creates the spark. Rather it is that the static charge has built up on you, and after stepping out and onto the ground, contact with the car door can cause a spark.

I've noticed this most often in winter, when I suppose conditions are more apt to create a static buildup.

However the spark is well away from the gas filler opening.

I also always touch the gas pump or another metal object before touching the filler nozzle. That way any charge is harmlessly dissipated.

quote:

Originally posted by scott9282:
However the spark is well away from the gas filler opening.

The gas pump nozzle is the only thing grounding the car. So when you are charged and touch your car, a spark can appear inside the gas filler opening. Gasoline vapours escaping the gas tank can become ignited.

Have seen a video circulated at work through safety section showing a gas tanker driver checking on the level in his tanker whilst off-loading, due to it being night time the driver decided to use the light on his mobile phone. this actually caused a large explosion so not neccesarily the call on a mobile but maybe other peripherals that can cause a spark.

quote:

Originally posted by Don Key:
Have seen a video circulated at work through safety section showing a gas tanker driver checking on the level in his tanker whilst off-loading, due to it being night time the driver decided to use the light on his mobile phone. this actually caused a large explosion so not neccesarily the call on a mobile but maybe other peripherals that can cause a spark.

If you are referring to the much posted Shell oil tanker video, it was a cigarette lighter he was using, not a cell phone. Here is the news report that went with it:

Fuek tanker fire

quote:

Originally posted by C128:

quote:

Originally posted by scott9282:
However the spark is well away from the gas filler opening.

The gas pump nozzle is the only thing grounding the car. So when you are charged and touch your car, a spark can appear inside the gas filler opening. Gasoline vapours escaping the gas tank can become ignited.

The risk is not stepping out of your car and touching the car (closing the door). The risk is getting out of your car and NOT touching the car (not closing the door).

While you are sitting in your car waiting for the gas to fill, you are frequently isolated from any of the metal components of the car. That means that if you have not closed the car door, you still have not grounded yourself to the metal chassis of the car by touching the door.

The first grounded component the person then comes into contact with is the filler hose. A spark discharge just outside the fuel tank is where the fumes would be concentrated while also having an oxygen source. Touching the door or other metal part of the car puts your body at the same potential as the chassis and the filler hose.

By the way, the static discharge from your body into the chassis of the vehicle will not cause a spark between the vehicle and the pump for two reasons. First, because the filler hose is already in close contact with the vehicle. Secondly, the charge on your body will dissipate across the entire surface of your vehicle, so the resulting potential between your vehicle and the filler hose is negligible.