"News reports of disasters often quote witnesses who said they heard some sort of explosion connected to the event. While deaths, injuries and damage resulting from explosions are devastating in every way, there are distinctions in the model fire codes among explosion types. In general, an explosion is the rapid and violent expansion of gases, which may include a shock wave, that can disrupt materials and enclosures in the vicinity. Explosions can result from chemical changes (such as rapid oxidation), physical changes (such as catastrophic failure of pressure vessels), or atomic changes (nuclear fission or fusion). The model codes differentiate between two types of explosions based on the shock wave travel speed. […] The distinction between deflagrations and detonations exists to establish the code requirements for explosion control. In general, the codes allow deflagration effects to be mitigated through explosion relief, explosion prevention systems, or barricades. Meanwhile, items that detonate must be separated by barricades that are designed to withstand the rapid release of energy in an explosion and are fully confined, partially vented or fully vented, or by another effective method of shielding from explosive materials by a natural or artificial barrier. Explosion control is a sophisticated engineering challenge that should be addressed only by qualified personnel."
Coffee Break Training - Fire Protection Series No. FP-2014-48
U.S. Fire Administration: http://www.usfa.fema.gov/