AndyMA said:
I'm sorry to say this but what you state is totally incorrect and dangerous. It shows a total lack of understanding about electricity and as an electrical engineer I feel I have to step in and set the record straight. You do not create static electricity with conductive surfaces. You create it with friction on non conductive surfaces. Think about walking across a rug and then touching something conductive or another person -snap a spark created totally from friction on non conductive surfaces.
This same kind of friction can be created by the diesel fuel rubbing on the plastic can during filling. Apparently if the can has ever been used for gas, and is swithed back and forth between diesel and gas there is a film left that is particularly prone to creating static sparks and setting off explosions. I believe ti results in static generation when the gas rubs on the diesel film if I remember right. The Consumer Product Safety Commission published a special alert on this a few years back due to some explosions. You may get away wiith filling diesel and gas can's for years in the bed of your truck untill that one time when atmospheric and other conditions are just right and boom.
Also just another correction from some other posts, the tires on a vehicle are almost perfect insulations, just adding to the ability to created static electricity while filling a container in a vehicle regardless of whether it is conductive or not. The bed liner only makes the situation worse. Some approved containers also contain trace materials to make them slightly conductive.
So just a little advise from someone who gets to read the consumer product bulletins, fill your containers on the ground.
Andy
Well.....
tires have a high carbon content and are not all that great an insulator. I have been going back and forth with someone else on this topic, with no real resolution since there isn't anything major on the web about the conductivity of tires vs. vehicle static buildup (although there are a lot of people trying to accumulate IP with ideas in this direction if you do a search on the topic).
The issue of alternating the use of gas and diesel seems more to do with the resulting flammability of the vapor:
"the atmosphere in contact with the rising oil surface is not enriched to bring it
[gasoline vapors] out of the flammable range. If circumstances are such that a
spark should occur either across the oil surface or from the oil surface to some
other object, the spark occurs in a mixture that can be within the flammable range,
and explosion can result."
(from:
http://www.ntsb.gov/Recs/letters/1999/H99_33_34.pdf )
They are vague on the static source in the NTSB instance cited, they supposed sloshing fluid but really no one knows (maybe he was wearing synthetic long underwear that day?). The issue I have is that the flowing non conductive fluid (in the flowing fluid, for instance, for a hose going to a container) will result in the transport of charge, but the charge in an insulating container will tend to be distributed in the fluid. Charge mobility will be fairly poor (it is supposedly an insulating fluid and container). If the fluid was conductive, the charge would fairly rapidly concentrate on the surface-- or, for instance, on a metal can over time if the charge bleed off was slow enough which may occur for a conducting can being placed on a bedliner vs. the earth.
The argument that the fluid surface would accumulate enough charge from splashing/flowing/etc. for a plastic container being filled, and possible discharge from the fluid surface to the grounded nozzle with the fuel air mixture in the flammable range would apply whether the container was on the ground or in a truck bed. The results are less disastrous with the container on the ground though. [note that almost always the spark would not ignite like an FAE since the gas exceeds the flammable range close to the fuel surface. My guess is that there are a lot more sparks flying out there than people think!
]
I still believe that the reasons for specifying plastic containers are to be filled on the ground is for secondary not primary reasons, as alluded to in my previous post.
I don't have to play an electrical engineer on TV, since I did it the hard way