The answer is more the volitility of the fumes.
Gasoline vapors are way easier to ignite, are present at much lower temperatures, explode once ignitied, and continue to burn till all the gasoline is gone.

Diesel normally does not have ignitable vapors.

But I will tell you a story.

One night when I was driving over the road I was in a rest area in the middle of nowhere USA.
A guy comes staggering up to my truck asking me to get him to a hospital. His face was very red and he had a strange looking head of hair. It was a frizzy afro looking hair, but it looked like he was on a motorcycle doing about 60 without a helmet.
I asked what was wrong.
He was a truck driver.
His fuel guage did not work, neither did his flashlight.
So to check his fuel he took the fuel cap off and held a Bic lighter by the opening and was peering into the tank to see how much fuel was in the tank.
The tank he did this on was the one with the return fuel line in it.
The hot fuel out of the return line did fill the tank with diesel fumes.
The Bic lighter did ignite the fumes.
It did flash out of the tank and singe his eyebrows, eyelashes, and the front and sides of his hair since he was looking trying to see into the tank with his face down close to the opening.
As soon as the vapors were burnt, the fire went out even though there were 70 or so gallons in the tank.
I had no idea where the closest hospital was so I called and got the state police to help him.
Nothing was damaged other than the drivers hair and face.
He was OK after he had some burn cream applied to his face thanks to his glasses.

Moral of story,
Diesel can have fumes that will ignite on your truck.
If it happens it is not nearly as catastrophic as it is with gasoline.
Some of the fuel injected gasoline cars and trucks have return lines on them that introduce hot gasoline back into the tank that make them even worse than normal gasoline vehicles

 

i dont think there are too many people who check how much fuel is in their tank with a lighter
im just wondering why he thought that would be a good idea

 

Well the only explanation I can give to that is...it takes all kinds.
Even the ones with room temperature IQ's have their place in life.

 

I've heard and seen numerous videos of diesel igniting from static electricity on hot days, in a quarry, never in a pickup truck. Once the fuel is over 125 degrees it has reached its flash point, now sticking a fuel nozzle in the tank and creating a spark and you've got a problem. The potential for a problem exists which is why they made this law.

 

Static spark can ignite fuel vapors. Womens clothing is more often made of synthetics which in turn makes easier static. Static near the nozzle and the fume source can start a nasty flash fire.

As far as the vehicle running, I can understand moving parts and all, but I dont see how a properly running vehicle creates any real world danger. In fact I leave my gasser running most of the time.

Hopefully I dont find out that I am wrong the hard way.

 

I can't think of a better reason. Better safe than.........

Pop

 

i leave mine running... i have not ever seen or heard of anyone getting blown up at a gas station unless they did something STUPID, like holding a LIGHTER up to your FUEL INLET..! even a slight breeze will carry away most fumes... and diesel fumes are MUCH harder to ignite than gasoline fumes... also... our mules can fill up at the pumps the big rigs use, so if you use those pumps, there are usually no other cars around, so you do not have to worry about your truck igniting any stray gas fumes... one other thing... it is the law that you have to shut off a gas powered engine when you refuel, but i do not think that law applies to diesels... if it does then the cops don't care about the diesel trucks becuase i have NEVER seen someone who is refueling a big diesel truck shut it off when they are refueling... just my o2....

 

Not to change the subject, but isn't idling for prolonged periods adding unessasary wear on the diesel engine, unless they are idling in the 1200-1500 rpm range ? btw I shut my PSD down at fill up time '99 F250 w/167;000.

 

They ground the jet and there will be no sparks from static electricity during refueling. No static electricity = no BOOM. Do you ground your truck?

 

Jet A which is not that much different from #1 diesel will ignite from static electricity. When doing "over the wing" wing refuel which is the same as we refueling are trucks, in cold environments and fast flow, static electricity can build up and you will hear a crackling sound. It is rare but it does happens. I still refuel my truck running.

 

ok been reading evryones feedback on this how does shuting off your deisel engine stop vapors in the tank? how does shuting down you deisel cool the fuel below its flashpoint? or elinante static electricity? i get static walk ing on new carpet in a housse with no internal combustin engines. may be its left over from being in the semi that moved it.sorry for the sarcasim. a running deisel has no more ways to make ignition than a gassser turned off, nevermind the flash points and such. maybe im just not smart enough to understand the politics.

 

I have a feeling that everyone in here (including me) has probably missed the real reason why they instigated this law. Do you guys remember when cars (especially) those big boat ford cars (I say this because they recalled them) with the c6 used to go into reverse automatically? If this happened while you were filling her up you'd have a huge mess and possibly some dead people if the condition were right (or should I say wrong?) In Alaska when it is really cold (really cold here is -60 degrees) everybody fills there stuff up with the engine running. I once saw a lady that was talking on the good old cell phone drive off with the hose and nozzle still in her car while refilling. She took about half the pump with her before she figured it out. Luckily the pump shut off automatically and almost no fuel was spilled. Honestly, I think the reason why we have laws like this one is because some people are just too dumb to be entrusted with everyone else's lives.

 

i had a buddy do the same thing in a service truck . it had break away connections no fuel was spilled there either, my buddy didnt even know it till he got home . bad news his truck had name and phone # on it before he got back his boss was calling him WHAT THE . cost like 1800$ to fix.

 

Interesting thread...lots of opinions.

I leave my vehicles running while I fuel.....all of them. I also touch the vehicle and the pump prior to turning the pump on to discharge any static to either one.

 

If the aircraft is bonded to the refuel truck properly you shouldn't.