What is BLEVE and why is it a critical scenario in source models?

• A. It's a chemical reaction in air.
• B. It's a type of diesel engine explosion.
• C. A Boiling Liquid Expanding Vapor Explosive occurs when a vessel containing pressurized liquid fails; hazard includes rapid vapor release and overpressure fragmentation.
• D. It's only a small spark hazard.

Answer: (C)

BleVE stands for Boiling Liquid Expanding Vapor Explosive. It occurs when a vessel containing pressurized liquid fails catastrophically, causing the confined liquid to flash to high-pressure vapor almost instantly. That rapid vapor expansion creates a powerful blast overpressure and can rupture the vessel or surrounding structure, throwing debris. The combination of a violent overpressure surge, potential fragmentation, and a large vapor cloud (which may ignite if flammable) makes BLEVE a severe, multi-faceted hazard. In source models, this scenario is critical because it represents more than just a leak or fire—it can produce far-reaching blast effects and debris patterns that dramatically affect hazard distances, response planning, and mitigation strategies. It’s not merely a chemical reaction in air, not a diesel-engine explosion, and not simply a small spark hazard, which is why the detailed vessel failure and rapid vapor release character of BLEVE is the correct and most comprehensive description.