Fire management consists on the design of adequate mechanical ventilation system to allow the smoke extraction within a short time in order to insure the safety of the personals. The zonal calculation method based on global estimations is widely applied to car parks. This method does not permit to test the fire extraction system and to see what happens locally. In this context, the present study report sample results obtained by computational fluid dynamics (CFD) for the ventilation and fire dynamics in a car park basement using the NFPA (National Fire Protection Association) standards. The tenability criteria are the temperature and soot visibility. The fire dynamic simulator (FDS) is used in the present study and which is based on the large eddy simulation (LES) method. Two cases are studied: car park with and without jet fans. It is shown that the jet fans enhance the smoke extraction by reducing the dead spots in the car park.