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Dust Explosions





Pyro Man
Not many people know this, but dust is one of the most explosive things in the world. When fine particles of dust build up and a spark or fire is present, it can cause an enormous explosion.

In 1982, a custard factory in England caught fire, and all the custard powder dust in the rafters wafted down and it blew the roof off the factory. But the funny side is, what does custard powder, heat, and water from fire hoses make? Gallons of the stuff came out of the building.

But dust is very interesting, although its hard to get a dust explosion to work.
HoboPelican
Pyro Man wrote:
Not many people know this, but dust is one of the most explosive things in the world. When fine particles of dust build up and a spark or fire is present, it can cause an enormous explosion.

In 1982, a custard factory in England caught fire, and all the custard powder dust in the rafters wafted down and it blew the roof off the factory. But the funny side is, what does custard powder, heat, and water from fire hoses make? Gallons of the stuff came out of the building.

But dust is very interesting, although its hard to get a dust explosion to work.

I don't think dust explosions are that uncommon. I seem to remember hearing about grain silos exploding now and then.

Just did googled "dust explosions" and got a whole slew of pages.
superbonfire
a little off topic but, im allergic to dust
allergies suck
HoboPelican
superbonfire wrote:
a little off topic but, im allergic to dust
allergies suck


Then you really should avoid dust explosions.
Laughing Laughing Laughing
Moey
HoboPelican wrote:
superbonfire wrote:
a little off topic but, im allergic to dust
allergies suck


Then you really should avoid dust explosions.
Laughing Laughing Laughing


Allergies or not, I think that everyone should try and avoid them Wink

My science teacher said they happen in mining shafts that have a lot of coal dust I think. He told us about the ones in grain silos too.
UnderClassman
You can also get a desired reaction from flower. That's right, every day common flower... The stuff you used to bake that cake the other day, the stuff you use to make doe. Flower.

Flower, little volume, and heat. Isn't it obviouse? HEAT!
squirrelmaster
i think that dust explosions can happen on a smaller scale too.
i had this REALLY old power supply that hadn't been turned on in years, and it gathered a lot of dust. When I plugged it in there was a big spark inside, and a flame engulfing the inside of it. Although to put it out i just blew on it! Laughing

Do you think there would have been a more damaging explosion(like the case bending, not just a flame igniting) if the dust were more confined? Think
Soulfire
You know what else is seldomly thought about? The fact that velcro (spelling?) is highly explosive in pure-oxygen environments.
ocalhoun
In the middle ages, it was strictly forbidden to run mills at night.
The mill would produce a lot of dust, and the only lights available were open flames. Dust explosions have been a problem for a very long time.
UnderClassman
What causes the explosions?

Does the heat travle from dust partical to dust partical creating a span of heat so great that it ignites the dust itself causing a burst of exothermic reaction? Is it like connecting the dots?

Wouldn't this make sense?

What is heat? a form of energy. What is the result of a bomb? an explosion (release) of energy. So if the heat (energy) travles from partical to partcial, that would spread out the energy creating a bigger potential energy blow. And then when the dust ignited... Kaboom! The dust would be on fire and leting off enough energy (or heat) to be viewed as an explosion.

Can anyone disprove this?
nealio1000
Pyro ManNot said: many people know this, but dust is one of the most explosive things in the world. When fine particles of dust build up and a spark or fire is present, it can cause an enormous explosion.

In 1982, a custard factory in England caught fire, and all the custard powder dust in the rafters wafted down and it blew the roof off the factory. But the funny side is, what does custard powder, heat, and water from fire hoses make? Gallons of the stuff came out of the building.

But dust is very interesting, although its hard to get a dust explosion to work.


i said: you are right. they try to prevent this from happening alot at school in the wood shop
odinstag
UnderClassman wrote:
What causes the explosions?



The Grain Dust when suspended in an air mixture is highly combustable. It is the same as a fuel air mixture like gasoline and air.

Pratty much anything that will burn will create an explosion when mixed witht he proper volume of air.

Quote:

Does the heat travle from dust partical to dust partical creating a span of heat so great that it ignites the dust itself causing a burst of exothermic reaction? Is it like connecting the dots?

Wouldn't this make sense?

What is heat? a form of energy. What is the result of a bomb? an explosion (release) of energy. So if the heat (energy) travles from partical to partcial, that would spread out the energy creating a bigger potential energy blow. And then when the dust ignited... Kaboom! The dust would be on fire and leting off enough energy (or heat) to be viewed as an explosion.

Can anyone disprove this?


That is pretty much it I guess.

Simply put, the dust is flammable. Mix a flammable with the proper amount of air and add a proper heat source and boom!
Lennon
The most common dusty factories include:

    Milling (flour or saw dust)
    Toner
    fireworks

Any others you can think of post them in.

Each industry is expected by quality regulation to insulate any electrical connections in dusty areas to avoid electrical ignition.
When I worked in a toner plant the toner is processed in a cool room, like a refrigerator, and significantly reduces the chances of spontaneous combustion. One spark in any of these factories could explode the building. If there is a high production level in the plant with lots of dust, the explosion could wipe out a 500m to 1000m radius. That includes destroying buildings etc.

It's happened before, we had a toner spill, toner dust filled the process room, we were all evacuated outside the building in 4mins, but there's not enough time to get 500-1000m away from the blast radius, so if there was ignition I would have been dead by now.

Spontaneous combustion occurs when two chemicals react with each other slowly, and when the reaction reaches a threshold level, the vapour ignites. Very rare, mostly only oxidizing agents. Most safety risks tell you to store some chemicals away from oxidizing reagents for this purpose.
UHF123
It's only organic dusts that are the problem I think. I've seen a custard powder explosion by blowing it across a hot element.
FunFunkyFritz
UHF123 wrote:
It's only organic dusts that are the problem I think. I've seen a custard powder explosion by blowing it across a hot element.

Na, not true. You can make anything flammable explode, you simply have to make sure that the mixture of oxygen and the flammable material is correct. Each molecule needs easy access to some oxygen in correct propotions, i.e. the material needs to be in vapor or dust form.

The reason why solid form explosives explodes is that it is mixed in correct proportions with molecules that produces oxygen when it reacts to heat and pressure.
UHF123
If it's flammable then by definition it will ignite and it will have a flash point when mixed with air (as a vapour). We're talking about powder that isn't flammable causing explosion.
Josso
A whole load of custard sounds kind of interesting, pretty cool if no-one was hurt. Probably quite expensive to clear up though Laughing. Man I'd just bring a bowl or something.
jwellsy
I prefer a good old fashioned BLEVE.
Boiling Liquid Expanding Vapor Explosion
It's when a fire impinges on a closed cotainer with a liquid in it.
The liquid boils and increases the pressure inside the container.
The tank will ping as it deforms before it catastroficly fails.
When the tank does fail the boiling liquid is atomized into a vapor cloud.
Then BLAM!!!
Here's a small one at about the 6min mark.
http://video.google.com/videoplay?docid=1505191406742106917&q=bleve
FunFunkyFritz
UHF123 wrote:
If it's flammable then by definition it will ignite and it will have a flash point when mixed with air (as a vapour). We're talking about powder that isn't flammable causing explosion.

Sorry, i didn't mean flammable. I was trying to say that you can make "anything that burns" to explode - organic or not. It's just a matter of temperature, pressure and mixture.
Egmond
We always learn even milk is explosive, if you make powder of it Very Happy
squirrelmaster
milk explode??? i would love to see that one!! Laughing
i guess by theory it would explode, but even though i know it can its still funny to imagine milk doing that Confused
odinstag
UHF123 wrote:
It's only organic dusts that are the problem I think. I've seen a custard powder explosion by blowing it across a hot element.


No, some metals work also like aluminium powder.
odinstag
UHF123 wrote:
If it's flammable then by definition it will ignite and it will have a flash point when mixed with air (as a vapour). We're talking about powder that isn't flammable causing explosion.


Powdered aluminium.
FunFunkyFritz
squirrelmaster wrote:
milk explode??? i would love to see that one!! Laughing
i guess by theory it would explode, but even though i know it can its still funny to imagine milk doing that Confused


I was about to do a fake image travesty of "Got Milk" and Usama, but i don't have the energy right now. Feel free to use the idea Smile
UHF123
odinstag wrote:
UHF123 wrote:
If it's flammable then by definition it will ignite and it will have a flash point when mixed with air (as a vapour). We're talking about powder that isn't flammable causing explosion.


Powdered aluminium.


Won't explode, it'll burn rapidly but this is not the same as an explosion. Gun powder won't explode. It has to be confined and ignited with a detonator to explode. Organic powder explosions are different as they explode in a similar manner to gas.
Jaan
Saw dust explodes too Very Happy , but not very easily. I wonder what would happen if different dust types were mixed???
Billwaa
dust explosions never happened to me, nor I ever seen one, I bet it will be very cool to see one.
cannibalsmurf
They pulled the dust explosion thing on Myth busters. Wile it's true that dusts can explode they have to have the perfect fuel-air mixture so they relly aren't that common.
Mannix
It all has to do with surface area, if you try to light a block of steel on fire you will fail, if you try steel wool, it will quickly burn. if you try and light a large block of wood on fire, it takes ALOT longer than, say, sawdust. I've tried the sawdust myself, and it is pretty impressive(I lost an eyebrow trying it). In air of course the right fuel-air mixture is necessary, and of course what the dust is from matters(it has to be able to be burnt). To really be considered an explosion it needs to be contained, I've seen what can happen to silos, and it is pretty bad.

http://www.osha.gov/as/opa/foia/hot_6.html and that's a concrete structure.
largelyobscure
Yeah, the powdered milk will definitely explode, but it has to be just right or it will either smother or nothing. My friend has this burn barrel out in a rural area and we were bored in the summertime and there really wasn't anything else to burn in the barrel but it was still burning quite alright. Well, the only thing around was these big sacks of powdered milk.

My friend through a whole hard sack of it and it didn't really do anything except to stink and smother, but when I got a sack of the stuff, opened it up and sprinkled it over the fire, if flared up significantly. Eventually it did a good flare up; I know that if the burn barrel had been contained more it would have done more, but eventually I got it just right and it made one heck of a boom.

You wouldn't think that of powdered milk though, but same like the flour powder in that bakery somewhere recently that exploded, enough of it in a contained area can cause a really serious situation depending upon the factors. I ended up burning the hair off of my hand doing that thing with the powdered milk; I can't imagine being close to something like what happened at that pie factory or bakery or that really nasty one that happened at the toner factory, where the toner dust exploded... now that is some nasty NASTY stuff to smell burning.

Anyway, that's all I have to say about that.
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