WHAT IS A BLEVE?

  http://www.hrdp-idrm.in/e5783/e17327/e27015/e27750/

For a BLEVE situation following four conditions must be present:-

1. There must be a substance in liquid form. Most of the destructive BELEV's that have occurred have involved flammable liquids and liquefied flammable gases. BLEVE can occur with any liquid, even water. The only difference is that with non¬flammable liquids there is no fireball. However, there will still be damaging effect including the propagating of creaks in the structure of the container together with possibility of subsequent failure and propulsion.
2. The liquid must be in a container like sphere, bullet, and road/rail tanker.
3. The contained liquid must be at a temperature above its normal boiling point at atmospheric pressure at the time container allows the pressure inside to build up above atmospheric pressure, the fluid, in the container is able to remain in the liquid state, even through its temperature is above its normal boiling point. This increase in pressure raises the Boiling point of the contained liquid above its boiling point.
4. There must be a failure of the container in order to have BLEVE. This container failure can be due to following courses:

• Flame impingement.
• Internal structural weakness of the container
• Failure of improperly designed SRV
• Impact from a mechanical cause such a road accident, tanker derailment allowing flammable liquid to flow out.