From: firstname.lastname@example.org (George Herbert)
Subject: Re: Is flash powder consider a high or low order explosive?
Date: 24 Jun 1999 18:39:03 -0700
>BLEVE? (may overlap #6). Boiling Liquid Expanding Vapor Explosion.
I thought BLEVE was Burning Liquid Expanding Vapor Explosion, not Boiling.
I don't regularly read the firefighter magazines, but I recall seeing some
discussion of it in the late 80s early 90s timeframe after a few incidents.
Superheated water isn't technically a BLEVE, it's just superheated liquid
flash vaporizing, which is unpleasant but not nearly as bad as say,
superheated propane flash vaporizing while burning and resulting in
a near-instantaneous combustion of the whole load.
There's another nifty effect which isn't quite in any of the
categories under discussion... if you have a tank full of
flammable liquid which floats, and a bit of contaminate water
at the bottom of the tank, the tank is highly dangerous if the
top starts on fire. The flammable liquid will get heated in a
zone moving down the tank, convecting some but generally with
a hot top zone and a cooler bottom zone, until the hot oil/gas/whatever
hits the bottom and flash vaporizes the water at the bottom,
which blows all the oil/gas/whatever out the top at once.
Major pain for firefighting in oil production and storage
facilities, because it makes it very dangerous to approach
tanks on fire.
-george william herbert