Studies on smoke movement in stairwell induced by an adjacent compartment fire

Experiments were conducted to investigate the smoke movement in a full-scale six-storey stairwell induced by a fire in an adjacent compartment. The smoke flow pattern in the stairwell was observed with vertical temperature and velocity field distribution measured. Corresponding Computational Fluid Dynamics (CFD) simulations were carried out by Fire Dynamics Simulator (FDS) and compared with the measured data. It was observed that the smoke flow moved upward in circular patterns and formed vortices under the stairwell tread of each storey. The smoke temperature was found to generally decrease exponentially with height in the stairwell, except the top and the bottom levels, where the temperature is relatively higher. The upward smoke flow velocity first increased and then decreased with height. The predicted smoke flow temperature and velocity by FDS were shown to agree well with the measured values. Temperature distribution is identified to be a key factor affecting the smoke movement in the stairwell.