When a fire occurs in a building

the majority of casualties are caused by fire smoke.In high-rise buildings

because of the stack effect

smoke can easily spread upward

but different states of opening will affect the spread speed.A mathematical model of fire smoke movement in a multi-layer building is described with numerical method as well in this paper.The movement of fire smokes in a multi-layer building is simulated using PHOENICS3.5

and the movements under different states of opening are then compared and analyzed.The advantage and feasibility of PHOENICS used in numerical simulation of fire smoke movement are briefly illustrated.The applicability of numerical simulation of fire smoke movement under different states of opening is also demonstrated.