Sunday, 24 March 2013

The Tremendously Explosive Power Of Flour

image credit: cc

Most of us know that flour is an essential ingredient in pizza dough and bagels, but as long as we can eat the final baked product, our interest often doesn't go much further. But did you know flour can explode? Flour dust suspended in air is explosive - as is any mixture of a finely powdered flammable substance with air. It is capable of destroying entire buildings.

4 comment(s):

Anonymous said...

Mr. Wizard (Don Herbert) demonstrated this about 55 years ago.

Anonymous said...

Time to ban it then.

Donald Sensing said...

Back in the 1980s, I was a staff officer of XVIII Airborne Corps at Fort Bragg, NC. The state found itself with a building that needed to be demolished, a pretty big one - IIRC, it was a large obsolete school building.

Somehow, the Corps' 20th Engineer Brigade managed to get the job. So they flew an exercise air assault out a demolition platoon out there and they blew the place down.

They used flour bombs throughout.

Flour bombs are actually simple to make. Ordinary flour is of course the main ingredient. When I learned to make them they key thing was using an igniter; we used powdered magnesium, which flashes very quickly. Mix it with the flour.

Flour ignites as an "aerosol," when it is suspended in the air. You can't stick blasting caps into a bag of flour and get an explosion. When the flour-magnesium mix is suspended in the air, you ignite a flame source and whoom. (A Special Forces NCO told me that he always just left a lit candle on the other side of the room. When the "aerosol" got there, the magnesium powder lit and it chain reacted

One thing that makes flour bombs so good for demolition is that they are low explosives. If calculated correctly, the building simply crumples rather than blows apart. This is what the engineers did. And they have enormous "pushing" power.

All in all, a very effective device.

Anonymous said...

ed in texas
Not just flour. You ever see a grain elevator blow up? There's usually not a lot of survivors nearby that knew what was going on. Once you get a half a mile or so away, you get 'there was a big BOOM'. Corn, wheat, soy, rice... anywhere they're milled and stored, you see things like lights with sealed glass over them, and a steel grid over that... kinda like in a refinery. For the same reason. Any kind of fine powder or mist, of a substance that has energy of any kind in it, is a reducing reaction waiting to happen.