Don't Want To Explode

[JamesDowning]

In most cases, when people pull into a gas station to refuel a vehicle, they open the car door, slide out of the seat, open the fuel pipe cover of the vehicle, touch the nozzle on the gas pump, and perhaps touch the pump to use a credit card--all before they insert the nozzle into the fill pipe. Any static charge that was picked up in the car is dissipated several times.

When you are dealing with a statically isolated item such as a plastic fuel can, you need to be sure to bring yourself to the same voltage potential as the can before bringing the nozzle near the can.

A plastic can bouncing around and rubbing the holder is much like taking a balloon and rubbing it on anything. The balloon looses or picks up electrons. This is the same phenomenon as when you get out of your vehicle and rub against your seat.

You want to dissipate the voltage difference before you fuel... you dissipate the voltage difference by contacting the fuel can while you place it on the cement.

Voltage is all relative, and as long as the voltage difference between you, the nozzle, and the can is low enough not to spark, you should be fine.

It is NOT about grounding the fuel can to the vehicle itself...

 

[R_Lefebvre]

That makes a little more sense. The one vid with the fuel can in the back of the pickup, it looked like he had a bedliner. I could see having a can in the back of a truck with bedliner could be a problem. Any kind of grounding strap would solve the problem. In fact, I think I've seen the regulation in Ontario, it says any tank in the back of a pickup must be grounded to the frame. That makes more sense.

 

[ntsqd]

It just dawned on me that the covers on the filler handles, at least here on the Lower Left Coast, appear to be vinyl.

HUH? :Wow1:

Perhaps since they are nearly always black (except for the diesel's which are green) maybe they have enough carbon in them to make them anti-static discharge (ESD)?

Not all that long ago the handles were bare metal. Touching those would make you the same potential as the filler nozzle. Perhaps some of the problem stems from our self service pumps and people's reluctance to handle a cold metal filler nozzle? I can see that being an issue where it really does get cold. Then again if it were really cold wouldn't those people have gloves on?

Based on JamesDowning's idea it would seem that the rule that the filling must take place on the ground is more to force the handling of the container than the placing of the container on the ground. If all the rule said was to touch the container first then people would be less likely to do so.

In other words, the rule is manipulating our behavior beyond what is necessary to gain full compliance.

 

[charlieaarons]

Alaska in the wintertime has very low absolute humidity. People always wear gloves when pumping fuel. The flash point of gasoline is ~-76 F.
I see pickups all over the place with bed mounted tanks. If they are diesel, no problem. If they are for avgas, I would bet the FBO insists on a grounding wire before pumping starts.
Here in the winter on a cold sunny day static builds on any object moving relative to another indoors, especially when insulated on carpeting; people vs. furniture, cats. I do not see why outdoors should be any different.

Charlie

 

[JRH_PowerWagon_06]

I believe the gas flowing through the nozzle generates some static charge. That's why you are supposed to keep the metal end of the nozzle in contact with the side/lip of the gas can, whether it is metal or plastic.​

This is from a safety brochure on gas:​

When dispensing gasoline into a portable gasoline can, use only an approved
container. Always place the container on the ground and keep the pump nozzle
in contact with the container when refueling to avoid a static electricity ignition of
fuel vapors. Containers should never be filled inside a vehicle, in the trunk, on the
bed of a pickup or flatbed truck, or on the floor of a trailer. The bed of the truck
and the bed liner act as insulators, as does the carpeting in a car or in its trunk,
which may allow static electricity to build up in the can while it is being filled. That​

static electricity could create a spark between the container and the fuel nozzle.

 

[robert]

I can't download the videos where I am to check, but it would be interesting to see in those accidents if the victims had a hand on the cans as they stuck the nozzle to them. I'm going to bet that they didn't. I'm also going to bet that if the can is sitting on your tailgate and you have a hand on it, reach over and grab the pump handle and bring it to the can while continuing to hold the plastic can, that there would be no differential- when you grabbed the handle you equalized the potential. It should be easy enough to check with a volt meter and a dry empty gas can with no vapor in it- no, I'm not volunteering.

That said, I imagine you could attach a grounding strap like we used on fuel trucks when fueling if you wanted to- two copper clamps with a length of copper wire between them. Clip it to the handle of each and you should in theory be good to go.

I did a search on the Mythbusters website but can't find an episode about the gas cans; I seem to recall seeing one though I can't remember the results.

Personally the only thing I use plastic cans for is the lawnmower and the one I occasionally carry on top of my bus. Both are small enough not be a problem to put them on the ground; the one that goes in the luggage rack of the bus is up so high I have to take it off to fill it anyways. I'll stick with my Wedco cans for the truck.


You could always add some of those Oh so stylish black rubber grounding straps that were somewhat popular back in the seventies on pimp cars. )

 

[nargun]

10 months ago there were bushfires burning about 3 km from our place, so I was avidly tuned to the Government ‘disaster’ radio station listening for updates, when an item came through that a petrol station 8 km the other direction was ablaze. More information was broadcast that a car had gone up in flames

A couple of days later the news came through that the person was filling a 5 litre container with petrol in preparation of evacuating, leaving it on the tailgate of her 4WD, It appears the nozzle wasn’t touching the can and a static spark ignited it.

It was also reported that the car was packed with the keepsakes she was taking to safety!

No idea why she was filling 5 litres; the next petrol station was 10 km in the safe direction. (one of the hints for bushfire planning is to ensure on 'catastrophic' days is that there is sufficient fuel in the car to reach safety)