TABLE OF CONTENTS This section of the guide focuses on predicting the heat transfer from area exposure fire plumes to adjacent surfaces. Area exposure fires are burning objects or fuel located adjacent to or near the surface being heated. For certain scenarios, the local fire exposure may produce a more extreme exposure than the hot gas layer that develops in the area of consideration. Some examples are open parking garages, large warehouses, and bridges and overpasses. To analyze these scenarios, one needs to have knowledge of the incident heat flux levels produced by local fire plumes.
The boundary condition between the fire plume and the structural element needs to be properly defined in order to predict the temperature of the structural element with time. This part of the guide develops heat transfer boundary conditions for two different types of exposure:
Bounding, or elements immersed in a fire plume
Specific geometries, or specific element shapes and orientations
Detailed modeling of the fire from first principles can also be conducted to predict the boundary condition; however, this type of analysis is not addressed in this guide. If detailed modeling is conducted, the model should be verified with existing data for similar configurations to validate predicted heat fluxes. Some additional data on gas temperatures and velocities generated by a fire plume are also included to aid in this type of modeling effort.
The fire exposure recommended for a bounding analysis will consist of a constant fire exposure. If a more refined analysis is required, guidance...
