Temperature development in steel members exposed to localized fire in large enclosure

Accurately predicting the time-temperature relationship in steel members exposed to localized fire in large enclosures is a key issue in the design of structural fire protection. Although numerous methods for predicting the development of steel temperatures in compartment fires have been proposed, heat transfer between steel and flame in large spaces is disregarded in these classical methods. On the basis of the lumped heat capacity method, a modified model for tracing the temperature profile in steel members exposed to fire in large enclosures is proposed. In this model, a localized fire source is treated as a single-point fire source in evaluating flame net heat flux to steel. The increase in smoke temperature is used as a basis to develop a new approach to accurately predict the development of steel temperatures in large enclosures under fire conditions. To validate the model and approach, experiments are conducted which show that the predicted temperatures are satisfactorily consistent with the experimental data. The conclusions and experimental data serve as reference for fire simulation, hazard assessment, and fire protection design.