Flashback

Unknown

Everything I have read about flashback says that it only happens at temps over 700, except for Whiz. His site says that you can have flashbacks at lower temps. Yesterday he was proven correct in my backyard. Whiz, I understand about VOC's, but I also think that lump dust may be a part of the problem, being that the dust is so highly combustible. I had a fire going for about 10 minutes at 350. I opened the lid about an inch or 2 as usual as a precaution, and Whoomph. A few minutes later, same thing. The rest of the day at the same temp and nothing. As the day went on the VOC's burned off so that ended that, but I wonder if the dust burning off had something to do with it as well. What do you think?

stike

DannyT,
i think you are correct.[p]dust is highly explosive... any fire with a lot of new lump is potentially flashback-worthy, though i never saw anything lower than 350 or so.[p]

Eggecutioner

stike,[p]I have had the same thing happen at similar temps. I attributed it to not enough air. Even though I had the draft door fully open and no daisy wheel. I think the new load of lump was restricting the airflow, or possible the holes in the fire grate were plugged with small pieces of lump. So I generally load the lump to the top of the fire ring and keep reusing it without adding more lump. Then when I need to go nuclear I clean all the ash and bits out with a shop vac. Reloading with the Large chunks of lump on the bottom. It hasn't happened since, and my eyebrows have grown back nicely.[p]Eggecutioner

Ziggy

Same thing happened to me yesterday! I've only had my egg for a few weeks so I thought it was something I did wrong. My thermometer was definitely not over 400 (and I'd just done the boiling water test). I still have my eyebrows - but boy did I smell like Santa - just came down the chimney![p]ziggy

The Naked Whiz

DannyT,
Yes, you and I both know now that flashbacks occur at lower temperatures. Dust can definitely cause a problem, although I don't think there is enough dust suspended in the air in the cooker while the fire is burning to make any difference. However, when I was a kid I used to take a candle and a plastic tube and blow flour through the tube into the flame. I could get some pretty bodacious plumes of flame. This is my destiny..... LOL!
TNW

stike

Eggecutioner,
yep
each particle is a little flash-point waiting to burn.
you open it and the O2 gets in there, giving it the fuel it needs.
WHOOMP![p]stab a wick into a 5pound bag of flour.
light it, and toss it off the roof like a bomb.[p]it will generate a humonstrous fireball of death and destruction.[p]much fun.[p]
...as an aside, i believe this is only one aspect of the flashback.... the other, when you have raging lump which is suddenly starved of oxygen (from shutting a lid, etc.), is a different animal, and the one we see more.

[ul][li]http://www.chemeng.ed.ac.uk/~emju49/SP2001/webpage/intro/intro.html[/ul]