Can LPG Tank Explode? and What is BLEVE (A boiling liquid expanding vapor explosion)
Could LPG tank explode?
There is no oxygen in the tank to support combustion. Even if there was oxygen inside the container it would have to be in the correct quantity for that to happen, and the air/fuel ratio for ignition of this LPG is fairly small.
All containers of LPG have pressure relief valves installed so that they are protected from over-pressure. This relief valve will open when the pressure gets too high so that the excess pressure can be released, and then close again.
What people usually call an “LPG tank explosion” is a rare occurrence called a BLEVE.
So, what is BLEVE?
BLEVE, or also called as Boiling Liquid Expanding Vapour Explosion, is a type of explosion that occurs when a vessel containing a pressurized liquid is ruptured.
There is no oxygen in the tank to support combustion. Even if there was oxygen inside the container it would have to be in the correct quantity for that to happen, and the air/fuel ratio for ignition of this LPG is fairly small.
All containers of LPG have pressure relief valves installed so that they are protected from over-pressure. This relief valve will open when the pressure gets too high so that the excess pressure can be released, and then close again.
What people usually call an “LPG tank explosion” is a rare occurrence called a BLEVE.
So, what is BLEVE?
BLEVE, or also called as Boiling Liquid Expanding Vapour Explosion, is a type of explosion that occurs when a vessel containing a pressurized liquid is ruptured.
When a container is exposed to sustained heat – say from the heat radiation emanating from a nearby fire – the liquid inside is forced to vaporize or boil, resulting in an increase in pressure within the tank. The relief valve in the tank will operate when this pressure reaches the set pressure of the relief device. The liquid in the tank will then fall as the relief valve releases the liquid vapour to the atmosphere. When the pressure decreases, the valve in the tank begins to close. The liquid is actually an effective element to cool part of the container wall which is in contact with it, but unfortunately the vapour is not.
However, if the heating does not stop, the liquid will continue to vaporize, the relief valve reopens, and the proportion of the container wall that has the benefit of liquid cooling will also keep falling. After a time, the portion of the metal wall that is un-cooled by the liquid becomes exposed to heat load,weakened, stretched and then eventually ruptured. As the tank comes apart large quantities of both vapor and liquid are released in a powerful explosion.
You might also want to read:
Facts about LPG.
How LPG regulators work.
However, if the heating does not stop, the liquid will continue to vaporize, the relief valve reopens, and the proportion of the container wall that has the benefit of liquid cooling will also keep falling. After a time, the portion of the metal wall that is un-cooled by the liquid becomes exposed to heat load,weakened, stretched and then eventually ruptured. As the tank comes apart large quantities of both vapor and liquid are released in a powerful explosion.
You might also want to read:
Facts about LPG.
How LPG regulators work.