Diesel Fire Risk

[noelex 77]

One of the great things about sailing is the continual learning curve. Our new boat has a Reflex diesel heater which is fantastic, but the surprise has been how easy it is to light the diesel in the heater. This just drips into the tray at the bottom.

I always assumed diesel was difficult to ignite. While it is obviously much safer than petrol or LPG, and will not explode like these fuels, it burns much more readily than I imagined.

I have never had an accident with diesel, but I now realise after many years servicing and repairing diesel engines that I have previously been far too casual dealing with spilled fuel after bleeding lines, replacing filters etc.

So stay safe everyone.

[deblen]

https://forestresources.org/digital-...-vapor-hazards


http://wyomingworkforce.org/_docs/os...-about-gas.pdf

[hellosailor]

Diesel, aka fuel oil, aka the stuff that the world's most powerful conventional bombs are made from? (Fertilizer plus fuel oil.)

Yeah, any good "fuel" has to have the potential to release lots of energy fast. I'm told that a pinhole leak in the high pressure side of a diesel fuel injection system can produce a very satisfactory diesel "fog". Fortunately, there's usually no fertilizer in the engine room.(G)

[JPA Cate]

The mind boggles at the permutations of fertilizer in the engine room!

Ann

[Pelagic]

Originally Posted by JPA Cate

The mind boggles at the permutations of fertilizer in the engine room!

Ann

Lol....that's where the Canadian liveaboards are growing their stash[emoji4]

[Jammer]

In practice the main risks are:
- an accumulation of diesel on absorbent, wicking materials -- rags, paper, carpet
- an ongoing fine spray. Doesn't have to be a fog. A hole in a 25 psi line will do it.
- hot diesel. Get the diesel above its flash point and it will burn like gasoline



Fiberglass and wood will burn too. Be careful.

[Simi 60]

Originally Posted by JPA Cate

The mind boggles at the permutations of fertilizer in the engine room!

Ann

400 litre sewerage holding tank and 7000 litres of diesel in ours.
1 huge sh1t bomb

[Mariano]

Just a simple experiment:

-put some diesel in a can and try with a match or a lighter = nothing happens

Diesel is one of the safest fuels (if not the safest), and it needs much more temperature (between 125,6 and 208,4 F*) to ignite with a flame than gasoline.

I have not tried yet with a spray over flame, but I guess its the same.......

Fair winds

Mariano

[a64pilot]

Originally Posted by hellosailor

Diesel, aka fuel oil, aka the stuff that the world's most powerful conventional bombs are made from? (Fertilizer plus fuel oil.)

The MOAB is actually RDX I think, and old form of plastic explosive.
However I know people that were pretty close to what was described as “propane bombs” in the first Gulf War, a fuel air explosive, but I can’t find any official confirmation. I haven’t really looked, I’m sure he knew what he saw.
We my friend saw it used at night, he was certain it was a Nuke, and that Israel had had enough of the Scuds.

[Mariano]

Originally Posted by hellosailor

Diesel, aka fuel oil, aka the stuff that the world's most powerful conventional bombs are made from? (Fertilizer plus fuel oil.)

I really hope you didn´t put "fuel oil" in your diesel engine, you´d have to replace your fuel tank and lines , or at least clean then with some strong stuff

Fair winds
Mariano

[noelex 77]

Originally Posted by Mariano

Just a simple experiment:
-put some diesel in a can and try with a match or a lighter = nothing happens

Mariano this was my belief as well, but it is wrong.

The Reflex heater does nothing more than drip diesel into a tray. There nothing under pressure in fact there is no pump or electricity consumed by the system at all.

Drop a match into the the diesel that has been dripped into the tray at the bottom of the heater and it will ignite the diesel and produce a very healthy fire in short period of time. This of course is exactly what you want in a heater, but not the way I imagined diesel would behave. Hence the warning.

[JohnHutchins]

Originally Posted by noelex 77

Mariano this was my belief as well, but it is wrong.

The Reflex heater does nothing more than drip diesel into a tray. There nothing under pressure in fact there is no pump or electricity consumed by the system at all.

Drop a match into the the diesel that has been dripped into the tray at the bottom of the heater and it will ignite the diesel and produce a very healthy fire in short period of time. This of course is exactly what you want in a heater, but not the way I imagined diesel would behave. Hence the warning.

Getting diesel to burn is a matter of getting it hot enough to do so. Whether it can be heated sufficiently with a match depends on its physical form, what it's in contact with, and how effectively the heat of the match is carried away from the fuel by those factors. Fine mist in the air = easy fire. Large pool of fuel in a can and you'll have a hard time getting it lit. Drop of fuel in a hot stove -- easy fire.

It's a safe fuel, but it is good to know the conditions that allow a heat source to get at least some fuel hot enough to burn

[estarzinger]

I once accidentally created a serious fire risk with a reflex heater.

Was in Iceland, was cold, and had wind coming down the stack. Almost got it burning well in the normal way a couple times but the wind snuffed it out. I did not think about it but that created two things #1 quite a bit of diesel in the pot, and #2 a decently high temperature in the Pot. We were tired and cold, so to get it finally going I put a short pour of meth spirits into the pot, and dropped a match in (actually had a more clever way to light it I learned in chile - used a metal oil can with meths in it, lit a drop on the spout and then shot a squirt into the pop - was like a flame thrower - this stopped the char build up the matches caused).

The whole thing burst into flames, flames licking outside the pot. Was afraid burning diesel might spill out onto the sole. Had to put it out with an extinguisher - which btw did the trick instantly.

But then we were cold and tired and standing in the cockpit because we could not breathe down below for a while.

it sucked at that moment.

but it was ofc all my fault - just being stupid.

[Mariano]

Originally Posted by JohnHutchins

Getting diesel to burn is a matter of getting it hot enough to do so. Whether it can be heated sufficiently with a match depends on its physical form, what it's in contact with, and how effectively the heat of the match is carried away from the fuel by those factors. Fine mist in the air = easy fire. Large pool of fuel in a can and you'll have a hard time getting it lit. Drop of fuel in a hot stove -- easy fire.

It's a safe fuel, but it is good to know the conditions that allow a heat source to get at least some fuel hot enough to burn

Thats why I stated ignition temps of diesel fuel (think it's called cetane temp)

Fair winds

Mariano

[Sailmonkey]

Originally Posted by Mariano

Just a simple experiment:



-put some diesel in a can and try with a match or a lighter = nothing happens



Diesel is one of the safest fuels (if not the safest), and it needs much more temperature (between 125,6 and 208,4 F*) to ignite with a flame than gasoline.



I have not tried yet with a spray over flame, but I guess its the same.......



Fair winds



Mariano

If you create a large surface area, like. Drip in a tray, the diesel burns readily. If you atomize (spray, mist, etc...) the diesel, it will burn more readily....there is more surface area and smaller particles to bring up to temperature.