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Under the Building Codes of Hong Kong Special Administration Region, the provision of refuge floors has been an indispensable element in their high-rise building design since 1996. A refuge floor is a designed temporary safe place to improve high-rise evacuation during fires. It is a fire-protected semi-permeable feature in buildings taller than 25 storeys. Direct cross natural ventilation by natural wind is an important design criterion of a refuge floor. It helps to prevent any smoke entering the refuge floor from logging and impairing the safe conditions of the floor. This paper reports a study of the wind flow patterns around a high-rise building with a refuge floor at wind incident angle perpendicular to the building. The study is based on CFD simulations which are qualified by wind tunnel data. The results revealed a smoke hazard potential if smoke is dispersed from the rear face of the building at a level closely below the refuge floor. Smoke may be logged inside the refuge floor area behind the internal blockage.