A Multi-Grid Model for Evacuation Coupling With the Effects of Fire Products

Abstract

In the study, influences of fire products on pedestrians are introducedinto a multi-grid evacuation model, in which the space is discretizedinto small grids with the size of 0.1 m times 0.1 m and each pedestrianoccupies 5 times 5 grid sites. The fire products affect two walkingparameters of pedestrians: the desired movement direction and the stepfrequency. The data of fire products are obtained from the simulationresults of the Fire Dynamics Simulator (FDS), a well-foundedcomputational fluid dynamic (CFD) program, developed by the NationalInstitute of Standards and Technology (NIST). With this model, weinvestigated the routes of pedestrians in fires, and the evacuationtimes in scenarios with different fire intensities, pre-movement timesor door widths. The results indicate that pedestrians will avoid movingtowards the fire source, small fire may make egress process fasterwhile large fire may reduce evacuation efficiency significantly, themovement time increases rapidly with the increasing pre-movement time,and the door width plays a more important role for evacuation in firethan normal condition. Furthermore, for the evacuation from a hall withtwo exits our model can reproduce the inefficient use of exits andpredict the optimal condition that results in least evacuation time.