An investigation of the impact of floor setting on airflow and smoke extraction in designated refuge floor

Refuge floor is used as a temporary place for evacuees residing in high-ris e buildings to take a short rest before taking further evacuation under fir e case. It is specified as a prescriptive requirement in the Fire Code of H ong Kong to provide designated refuge floors for high-rise buildings. To fu lfill its functions, a refuge floor must be a safe place for the evacuees. However, the safety of refuge floors under fire situations may be impaired if the floor is affected by smoke ingress from lower levels. The code presc ribes that cross-ventilation should be provided in refuge floor so as to pr event smoke logging. Even with sufficient cross-ventilation, the prevention and/or extraction of smoke logging into the refuge floor cannot be guarant eed. In fact, the airflow pattern and smoke extraction/dilution largely dep end on the floor planning in designated refuge floor. A study of the impact of refuge floor settings on the airflow around and inside the refuge floor is required and expected to provide some insight on the smoke movement pat tern. In this paper, the Computational Fluid Dynamics (CFD) method is emplo yed to predict and analyze the air movement around and inside designated re fuge floor within a high-rise building under different floor plans. The stu dy shows that the floor planning does affect airflow patterns and further t he smoke dispersion in the refuge floor.