Whether the balcony spill plume will rise as a free plume or curl inwards towards the atrium structure is determinant upon a number of factors. Admittedly, not all the factors are well investigated and wholly understood, resulting in limited guidance for Fire Engineers on the behaviour of the balcony spill plume in an atrium. The only relevant guidance states that “balconies which are shallow ( 2 m) will cause the rising spill plume to curl inwards towards the structure…… smoke-logging the balcony levels above the fire floor”. This guidance is based on limited number of smoke flow experiments in a model atrium. This research project is primarily a qualitative examination of the behaviour of the balcony spill plume in an atrium. Its main objective is to systematically investigate the effects of varying balcony breadths, plume widths and fire sizes on smoke contamination in upper balconies through experimental work. A series of smoke flow experiments were conducted using a one-tenth physical scale model representing a six-storey atrium building. The scale model simulated a fire in an adjacent compartment connecting a fully open atrium. Visual observations and temperature measurements of the smoke flows were carried out. From the experiment results, it was established that the extent of smoke contamination in upper balconies increased with decreasing balcony breadths, increasing plume widths and decreasing fire sizes. Further analysis of the experiment results showed that the aspect ratio of plume width to balcony breadth can be used to provide generic guidance to Fire Engineers in atrium design with respect to smoke contamination in upper balconies. In addition, an empirical correlation was developed to determine the height of smoke contamination and provide further guidance on smoke contamination in upper balconies. All in all, this research project has met its objective and achieved its desired outcome. It provides more details and improved guidance for Fire Engineers on smoke contamination in upper balconies by a balcony spill plume in an atrium.