Predictive Models for Thermal Hazards,
LOS ALAMOS NATIONAL LAB NM
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Many self-heating accidents with energetic materials have occurred when operations that have been done safely on a small scale are attempted on a larger scale. They have also occurred when a material is heated for a longer time or to a higher temperature than is normal for its processing or storage, such as might be caused by equipment malfunction or power failure. To prevent self-heating accidents, we must be able to predict the critical temperature for the size and shape of the material we are interested in. The critical temperature T sub c is defined as the lowest constant surface temperature at which a material of a given size and shape will self-heat to catastrophic destruction. This can be burning, explosion, or detonation, and because it is related to heat flow, it is dependent on the geometry of the system. As size increases, the critical temperature decreases. The shape also affects the T sub c, so that a sphere will have a higher T sub c than any other shape with the same radius or half thickness, as shown in Figure 2 for PBX 9501, plastic-bonded explosive.
- Safety Engineering
- Ammunition and Explosives