Why flour and sugar factories sometimes explode

This quick demonstration, with powdered coffee creamer, demonstrates why there are sometimes terrible explosions in factories that make harmless food like sugar and flour. Just a match and a little sprinkling, and you can see the entire thing go up in flame.


Every now and again you hear about building-wide explosions in food processing plants. It might be fair to assume that these explosions come from the places that have a lot of grease, or perhaps from the chemicals that make up that terrible rain-slicker like cheese that we feed to children. Not so. Most of the worst explosions happen in factories that make basic food like flour and sugar.

These factories, over time, can build up a layer of fine powder over the instruments, floor, and walls. As people move, and stir the air, that powder hangs everywhere, dispersed throughout the factory. We don't generally think of something like flour as flammable, and it's doubtful that it would go up in flames if you dropped a match in a bag of it. But the bag of sugar would be lacking one thing that all fire needs, easy access to oxygen. Tiny flecks of powder in the air are surrounded by oxygen. All that needs to happen is for some to catch fire. When they heat up, they stir the air, which gets more powder in the air, which also lights on fire. The reaction spreads outwards from its place of origin so quickly that it can explode the entire building. Obviously, it's hard to get the right concentration over the right area with just the right amount of heat, but it does happen.

And this demonstration shows how it works. The demonstrator simply sets up a flaming match and pours powdered coffee creamer over it. As the powder catches fire and heats, it flies up and sets more powder on fire. You can actually see the flames climb up the pouring creamer when the stream gets steady enough. This would probably not be a good idea to try out at home, or anywhere else were a little spilled powder spread the flames. Still, it's kind of cool to see the flames flare for something as mundane as creamer.

If they had used this demonstration instead of those terrible, sentimental flavored coffee creamer commercials when I was growing up, I might be a coffee drinker today.

Via icheme.org.



fuel-air explosion.