Using Software to Develop a Risk-Based Approach
An explosive, when heated, intentionally or unintentionally (e.g. fire), can produce a thermal explosion or even a detonation, producing a great deal of damage. Thermal explosions are complex events which typically include many chemical and physical processes such as heating, expansion, phase transition, chemical reactions, heat, and finally heat and momentum transfer. Evaluation of an explosion can involve a description of the initial material physical and chemical states, rate of heating, rate of decomposition kinetics, the changes in the explosive chemical and mechanical properties, rate of burning, transfer of explosive energy into thermal and mechanical energy (hydrodynamics), and, finally, amount of damage (violence).
Evaluation of Explosions by Modeling
Two main methodologies exist for modeling the explosion resulting from a vapor cloud explosion:
The explosion models include the following widely accepted approaches:
U.S. Army TNT Equivalency was based on the work of the U.S. Army. This model uses a proportional relationship between the flammable mass in the cloud and an equivalent weight of TNT and assumes that the entire flammable mass is involved in the explosion and that the explosion is centered at a single location. The model uses one of two blast curves, depending upon whether the explosion being modeled is a surface burst or a free-air burst.
U.K. HSE TNT Equivalency was based on the work of the U.K. Health and Safety Executive (HSE). This model uses a proportional relationship between the flammable mass in the cloud and an equivalent weight of TNT. It assumes that the entire flammable.
High Explosives: High Explosive Damage Assessment modeling has been conducted to evaluate the damage caused to structures within a facility as a result of a primary explosion and any accompanying secondary explosions. High explosive damage assessment models can also predict injury to an unlimited number of personnel in a facility. The principal use of such software is for site analysis of explosive storage and manufacturing facilities; however, the software can also be used to evaluate terrorism and sabotage threats to an industrial or military facility.
Explosion Modeling Software
We provide some potentially helpful links to a number of sources of geologic, scientific, and environmental software on our internet software links page. Some software that can assist with compliance, explosion prevention, explosion evaluation, and security are listed below:
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