Industrial accidents, fuel spills, and mechanical or electrical failures can result in large uncontrolled fires which impact the structural integrity of a building. The heat caused by the fire can cause structural columns and beams to fail, resulting in catastrophic damage to the structure.

A typical scenario is examined in which a fully protected beam is exposed to fire. The Fire Dynamics Simulator, an LES code developed by NIST, is utilized to model the situation. The critical output of the model is the heat flux and the temperature that the beam is exposed to. The model predicts the heat flux and surface temperature at each cell within the grid. These boundary conditions are then used as the starting point for a finite element analysis to determine the behavior of the beam under thermal stress.

The model results are compared to the ASTM E119 single point and average failure criteria.