The compartment fires have been studied through full-scale experiments, which were conducted in a compartment of size 4 m × 4 m × 4 m with a door of size 2 m (height) × 1 m (width). Four different experiments were performed, in which the width of the door was varied. The diesel fuel pan of 60 cm diameter was placed in the center of compartment. The maximum heat release rates measured were 502, 564, 446 and 124 kW for Exp. 1, Exp. 2, Exp. 3 and Exp. 4 respectively. The average hot gas temperature in Exp. 1, Exp. 2, Exp. 3 and Exp. 4 were found to be 266, 328, 314, and 174 °C respectively. In Exp. 3, highest heat flux was found to be 13.6 kW at ceiling. Further, the numerical simulations were performed for Exp. 1 and Exp. 2 experimental condition using Fire Dynamics Simulator incorporating different mesh sizes.