No, I’m not going to try this in real life! It’s research for a story I’m trying to write.
Say I need to dispose of a body in a shallow trench…or I’m a Buddhist monk trying to set himself on fire to protest the war…and all I have is diesel fuel, not gasoline.
What happens when you drench a body with diesel and try to light it, with a match or lighter?
(Yes, I write screwy stories!)
Need answer fast? (I hope not) 
Diesel fuel is kinda hard to light if you just have a puddle of it open to the air. You may have a really hard time lighting it with just a lighter or a match.
If you can get it to light, I suspect that it’s going to burn fairly slow at first. It takes a lot of heat to really get a diesel fire going. Once the fire gets hot enough, it will all burn pretty well. You’ll eventually dispose of your body in a ditch, but it’s probably not your best fuel for self immolation.
If you are expecting a big FOOF! like with gasoline, you are going to be rather disappointed.
I believe diesel is a lot more difficult to ignite than regular gasoline, so it seems like it would be silly to burn a body with it when gas is so freely available.
You will also get a lot of smoke. Burned like this; diesel does not combust completely.
When I was a mechanic at a car shop, we sometimes suspected someone had accidentally put gasoline in their diesel vehicle. A quick (and probably not safe) test was to pour a very tiny spot of the mystery fuel on the ground and try to light it with a butane mini torch. The gasoline would ignite, but the flame would usually just push the diesel around.
Jet fuel is essentially Diesel. In fact the US military uses a common jet-fuel/Diesel truck fuel for logistic ease.
Given how many flaming Jet crashes you see, I’d say it’s not that hard to ignite. In fact some memory says it’s got either a lower flash point or lower ignition point than gasoline.
The easiest way to ignite it is a rag soaked in it on the end of a stick using a butane lighter.
#1 jet fuel is kerosene with aviation-specific additives.
#2 diesel (and kerosene) have a high flash point of about 140 F. “Flash point” isn’t the temperature where the stuff will go “FOOF,” it’s the temperature where it will start giving off vapors which can go “FOOF” if an ignition source is present. If you want to ignite diesel or kerosene, you have to either have a wick, or heat it up near its flash point.
as a comparison, gasoline’s flash point is like -25 F which is why it ignites so readily.
There was an episode of Sherlock where a baddie had captured the heroes and was going kill them by burning them and the house they were in. She poured fuel all over them and the room then tossed a match on it. Nothing happened. They laughed at her for using diesel.
Here’s a video showing how different liquid fuels burn
Check out the combo Diesel / Jet Fuel JP8
Did you actually read your cite?
Emphasis added.
Also, there’s an entire section about how, as a diesel replacement for internal combustion engines, it’s not quite a perfect replacement because significant differences in combustion and compression behavior. In other words, it’s just like diesel except it’s easier to burn than diesel. Which means that diesel is harder to burn the JP-8.
QED.
When I was in the Boy Scouts (30+ years ago), we used to build bonfires and douse them with diesel fuel before lighting them. I don’t remember ever having trouble getting them to light. One time we used gasoline and it was a very different experience; the fumes had spread out and it made an impressive FOOOOMF and a bright fireball. But diesel always just burned slowly for us, no troubles.
One word of caution. The vast majority of clothing sold in the US is coated with fire retardant. Even with diesel fuel on it, you’ll get flames from the fuel but the clothing itself will just sit there acting like a candle wick. On a related note, some people claim that the wick effect will actually help once you get the fire hot enough to burn human fat. I don’t know. I’ve never tried to burn a body, but I have tried to burn clothing and it just won’t burn no matter how much diesel you pour onto it.
The trick is to evaporate enough of it to generate a flammable mixture. Failing in that, you can also atomize it very finely so that it has a large enough surface-area-to-volume ratio so that it behaves very much like a vapor. This is why grain elevators explode from time to time.
Plane crashes happen to be very good at atomizing jet fuel and exposing it to conveniently located heat sources, e.g. the hot parts of the engines. Once you’ve got a big cloud of hot stuff, it’ll ignite surfaces and puddles full of jet fuel, along with the flammable materials in the plane.
So if you filled a spray bottle with diesel, you might be able to ignite the resulting spray with a match, assuming the spray bottle could atomize diesel reasonably well. But you could point that intermittent flame thrower at a puddle of diesel, and the puddle wouldn’t light. You’d need sustained heat to get that puddle up past 140F, at which point it will generate enough vaporous fuel to sustain a flame.
Some distilled liquors are like that. The proof is too low for them to sustain fire at room temperature, but if you manage to warm up a shot glass enough, the hot liquor will generate enough alcohol vapor to sustain fire.
Home heating oil is just about the same as diesel fuel. It’s not all that easy to set aflame, which is why oil heat is safer than gas. The oil burner has a system for vaporizing the fuel to ignite it. If it gets spilled, it will pollute soil and smells awful, but will not explode from a nearby heat source or electric spark the way gas can.
[quote=“am77494, post:9, topic:717300”]
Here’s a video showing how different liquid fuels burn
[/QUOTE]Much fun! Mostly answered my question! Thank you! (I was surprised at how mild the gasoline flame was: I was expecting it to burst right up out of the jar and flash-fry the poor guy’s mug. I thought this was going to be some variety of Darwin Award video…)
Thank you everyone who responded. I’m always impressed at the trove of knowledge accumulated by the SDMB members.
Back in my younger, stupider days, I had fun with a campfire and a bag of flour. I could dust the flour in the air, over the fire, and get lovely little airbursts of flame. I never made a flour-bomb, but I’ve heard of 'em. Mini grain-elevators and a flame source. Bang.
note that home heating oil is not regulated for sulfur content and AFAIK now is dyed red, so don’t try running it in your diesel car or truck. At best you’ll trash the emissions equipment, at worst you’ll be fined for tax evasion.
(this isn’t any sort of rebuttal to the above post, just additional information.)
While atomization of jet fuel is one modality of post-crash aircraft fires, the comparatively low autoignition temperature of Jet A is a more common one. Jet A has a flash point of 105F, so it does need to be heated to support combustion. However, Jet A autoignites at 410F (gasoline is 853F). The back side of a jet engine, and recently used brakes are well above 410, simply letting Jet A hit those surfaces will ignite it, without an open flame. The Air China 737 that burned on the ramp in Okinawa in (I believe) 2008 was caused by a fuel tank leaking on the back of the engine. No atomization, just autoignition.
Airport fuel trucks have their engine exhausts discharge under the front bumper just to mitigate that hazard, amongst other peculiar design features.
To address the OP, the diesel would not ignite with a match if its temperature is below 140F. If you used a small torch (propane, mapp gas, etc), held in one spot, it will ignite in under a minute. The flame front will move across the surface of the fuel at about 100 feet per minute, which is quite slow and lazy. Once it’s burning well, diesel burns about one inch of depth every 8 minutes, so six inches will take about 48 minutes. I don’t know what it would do to your victim.
OTOH, if you want a big FOOF! that doesn’t disappoint, try using FOOF! Just douse your victim with that, and see what’s left of him (and you).
I’m imagining a propane camping stove, or perhaps a highway flare…
An ordinary match won’t last long enough, but a candle, perhaps, if held in one place for a long time?
My favourite chemical! Chlorine Trifluoride is my second favourite. I also enjoy the MSDS for VX.