A Comparison of CFAST Predictions to USCG Real-Scale Fire Tests

Abstract

The zone model CFAST was used to make predictions of single room preflashover fire tests conducted in a steel enclosure. These results were then compared with previously published measurements obtained in fire tests. Tests included diesel pool fires, polyurethane slab fires, and wood crib fires. Half of these tests used natural ventilation (window, 1/4 door, and full door) while the remaining tests used forced ventilation (0.25 m3/s, 0.38 m3/s, and 0.61 m3/s). With the exception of heat release rates, all CFAST inputs were selected without knowledge of the experimental results. Key variables compared include the upper layer temperature, the hot layer interface location, and ceiling temperatures. Overall, predictions made by CFAST were in good agreement with the data. There was a general tendency to over predict both the hot gas layer temperature and the boundary surface temperature which may be due to under prediction of boundary heat losses. Experimental results showed that heat release rates varied with ventilation configurations by as much as a factor of 3. This observation indicates that thewide practice of using free burn heat release rate data in compartment fire predictions can result in over prediction of compartment fire conditions.

Keywords

fire modeling real-scale testing verification and validation pool fires furniture calorimeter CFAST

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