This is the final installment of a three-part series about ethanol and reviews hazards and firefighter response procedures for ethanol emergencies in transportation and at fixed facilities. Emergency responders have been dealing with spills and fires involving gasoline and diesel fuel for over 100...
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I have seen references to explosions involving ethanol tank cars as BLEVEs. A BLEVE is a boiling liquid, expanding vapor explosion. Tanks that contain boiling liquids subject to a BLEVE are pressure tanks that contain materials like propane, butane and liquefied petroleum gas (LPG). Ethanol tanks are liquid atmospheric pressure tanks. Under normal conditions, the tanks are at atmospheric pressure. The types of materials subject to a BLEVE are gases that have been liquefied in order to ship larger quantities. Liquefied gases remain a liquid in the tank, above their boiling point because of continued pressure in the tank. They continue to be liquids as long as the pressure tank car is intact.
If a breach occurs to the container, all of the liquid in the tank car immediately turns back into a gas at once. This occurs explosively, often rocketing parts of the disintegrating tank car over 1,000 feet. Thus, the term BLEVE — boiling liquid in the tank, vapor expands as the tank is breached, occurring explosively. The main factor to bear in mind is that the power of a BLEVE lies in the release of liquid product that quickly (if not instantaneously) boils or evaporates into the vapor phase and combines with the surrounding atmosphere to form a combustible and explosive mixture. Tanks containing ethanol and its mixtures with gasoline exposed to fire can rupture because of excess pressure built up by flame impingement, but they do not BLEVE.
Thanks to Bridget Smale of Advanced Bio Energy corporate office, Fairmont Plant Manager Grant Johanson and Fairmont Plant Safety Officer Megan Williams for their assistance.
ROBERT BURKE, a Firehouse® contributing editor, is the fire marshal for the University of Maryland Baltimore. He is a Certified Fire Protection Specialist (CFSP), Fire Inspector II, Fire Inspector III, Fire Investigator and Hazardous Materials Specialist, and has served on state and county hazardous materials response teams. Burke is an adjunct instructor at the National Fire Academy and the Community College of Baltimore, Catonsville Campus, and the author of the textbooks Hazardous Materials Chemistry for Emergency Responders and Counter-Terrorism for Emergency Responders. He can be contacted at firstname.lastname@example.org.