View Full Version : Fire! how do you put out a alcohol fire
rocketsocks
05-15-2012, 02:15
An interesting question has come up.How do you put out an alcohol fire?
Assuming that you can see the flames the depriving it of oxygen by smothering it is the way to go
Water....that is why alcohol us used on boats for cooking.
Water....that is why alcohol us used on boats for cooking.
Water is still good for putting out a alky fire but after doing a google search I found that alcohol stoves are not used nearly as much on boats as it was 30 years ago.
rocketsocks
05-15-2012, 05:40
Water....that is why alcohol us used on boats for cooking.This is not so cut and dry.The MSDS,or material safety data sheet,says to use water,(Spray)very important,It further says not to use a stream of water.Other extinguishers include,dry chem,foam,each one of those works by smothering.Methyl alcohol is lighter than water,and therefore will float,methyl alcohol vapors are lighter than air and will therefore be found closer to the ground.If I was cooking on a shelter floor and a small enough spill were to ignite I would try to smother it with something say a bandanna.If the fire were larger than anything I could smother it with I guess water wouldn't hurt,or will it?What I''ve been looking for is if water can combine with Ethyl Alcohol and then change it's LEL or Low Explosive Level to make it so dilute as to not ignite.Have not found that answer yet,or if that is even the right question to ask.Anyone?
rocketsocks
05-15-2012, 06:56
Well folks Jackpot,our resident chemist "Perrymk"says the alcohol does not float and that there is a disruption in the chemical process where by adding copious amounts off water should put out the fire,and smothering it would also do the trick,but if you really want the skinny on his words,go to the 'cooking in a shelter Poll",for the some concise reading.....I did.Thanks Perry!
http://www.whiteblaze.net/forum/showthread.php?84112-Cooking-in-Shelters&p=1288693&viewfull=1#post1288693
garlic08
05-15-2012, 10:23
Perry is correct. If you add water to your alcohol stove, the fire will go out. In fact, this is a good way to simmer on an alky stove: add a capful of water at a time until desired flame height is reached. The water will boil off and you have to keep adding more so it is tedious, but it works.
I hadn't considered using small amounts of water to simmer. That's clever.
Odd Man Out
05-15-2012, 12:20
...Methyl alcohol is lighter than water,and therefore will float,methyl alcohol vapors are lighter than air and will therefore be found closer to the ground..
The density of the vapors is especially important for use on a boat, since in a boat, the dense vapors will settle to the lowest spot in the boat and accumulate. In the lowest level of the boat there is poor ventilation and the flammable vapors accumulate to the point they can explode (the boat is basically shaped like a big bowl - propane is especially hazardous). However, I wouldn't think this would be particularly relevant for an alcohol stove used outside or in a shelter where ventilation is not an issue. Plus if it is on fire, fumes are burning, not accumulating and alcohol fuel is much less volatile than propane or petroleum fuel. Ethanol vapor will be more dense than air. Methanol less dense (but only very slightly).
Spraying (vs pouring) water is probably recommended because while liquid methanol is less dense than liquid water, it is still miscible in water (i.e. will dissolve at any concentration). Spraying will make it dissolve faster. Ethanol is also miscible. Isopropanol is less soluble, but soluble enough to extinguish with water, and not used much as a fuel anyway.
BTW, we all know you don't use water to put out an oil/petroleum fire. On the local news the other day they had a dramatic demonstration put on by the fire department. They set up a typical household kitchen in on of their fire training buildings. They put a frying pan on a stove with one cup of vegetable oil and turned on the burner until the oil caught on fire. Then they used a long pole to pour one cup of water on the fire. The boiling water vaporized the hot oil and caused a fireball that instantly engulfed the entire kitchen. A person standing by the stove would probably have died. I always have known not to do this but I was shocked at the demo and how just one cup of vegetable oil, one cup of water, and a frying pan on a stove could cause so much devastation.
"The boiling water vaporized the hot oil and caused a fireball that instantly engulfed the entire kitchen."
Odd Man Out
You got the sequence wrong .
The hot oil vaporized the water
When water changes to steam it immediatley increases in volume 1200x
Odd Man Out
05-15-2012, 13:19
"The boiling water vaporized the hot oil and caused a fireball that instantly engulfed the entire kitchen."
Odd Man Out
You got the sequence wrong .
The hot oil vaporized the water
When water changes to steam it immediatley increases in volume 1200x
Ok, I should have said the boiling water NEBULIZED the hot oil. This causes a huge increase in the liquid oil surface area, increasing its exposure to oxygen, increasing the combustion rate. A similar effect to coal dust explosions. When particles of flammable liquid or solid are small enough and concentrated enough, they become explosive.
rocketsocks
05-15-2012, 13:33
"The boiling water vaporized the hot oil and caused a fireball that instantly engulfed the entire kitchen."
Odd Man Out
You got the sequence wrong .
The hot oil vaporized the water
When water changes to steam it immediately increases in volume 1200xOne cubic inch of water changes to 1600 cubic inch of steam,either way,it's a lot.
Odd man out,yes that is a crazy amount of flame,darn near a small mushroom cloud in the sky.I saw an episode of "The Myth Busters"where they tested this very thing,water on a grease fire,the flashing of water to steam in the presence of hot grease was yes,one of the most violent house hold reactions some one cooking in a kitchen would ever want to experience,much less in a shelter....all would/could be lost.This I have first hand knowledge of when my sister tried to make donuts after a school cooking class one day.As I recall the phone call went something like this.My sister to my mother on the phone;"It's OK mom,the fire department just left".Luckily a neighbor was home and came over,as her daughter was also one of the Chefs that day,she threw salt everywhere.My father then remolded the offending stove back stop and side wall with red brick,presumably to only have to do that once.True story folks.
baking powder will do the job, too
Odd Man Out
09-19-2018, 10:52
I love it when I'm reading through an old thread that has been resurrected and find a particularly good post I want to reply to, only to find it was one of mine from 6 years ago.
SoaknWet
09-19-2018, 13:22
Use to drink flaming alcohol while stationed in Germany in the 60��
Use to drink flaming alcohol while stationed in Germany in the 60��
that is what I wanted to say: drink it
Spilled alcohol stoves have caused a couple large forest fires in Colorado. The forest duff gets burning and spreads too fast to allow smothering.
Use to drink flaming alcohol while stationed in Germany in the 60��
I was stationed in Germany in the 60s too. I didn’t encounter any flaming alcoholic drinks.
Drink alcohol. Burn petroleum.
Wayne