For physical or ‘mechanical explosions’ a reaction does not occur and the energy is obtained from the energy content of the contained substance.’ Four methods used to estimate the energy of such an explosion are Brode’s equation, isentropic expansion, isothermal expansion and thermodynamic availability.
Crowl & Louvar …full reference needed.
“An explosion that does not involve any form of combustion or chemical reaction. The most common is the rupture/bursting of a pressure vessel, for instance a high pressure gas cylinder. When a liquid is stored at a temperature above its atmospheric boiling temperature the vessel rupture leads to a Boiling Liquid Expanding Vapor Explosion (BLEVE).
Reference: adapted from Schaschke, Carl. (2014). Dictionary of Chemical Engineering. Oxford University Press.
“Physical explosions are often the result of over pressurization during a fire. Depending on whether the vessel is full of liquid or not, the explosion may be hydraulic or pneumatic. The mode of failure is determined by the weakest feature of the containment. A pneumatic explosion is the more violent and gives rise to a large number of missiles”
Reference: Mannan, Sam. (2012). Lees’ Loss Prevention in the Process Industries, Volumes 1-3 – Hazard Identification, Assessment and Control (4th Edition).