Smoke contamination of balconies due to a channelled spill plume at a lower level in an atrium might occur during a fire and could affect occupant safety during an evacuation. Previous experimental work has investigated the extent of smoke contamination, and this work describes a numerical modelling comparison of the experiments using the Fire Dynamics Simulator (FDS) computational fluid dynamics programme. Temperature, severity and height of smoke contamination are selected as the key parameters for comparison. The predictions of severity and height of smoke contamination are generally similar to the experimental results using a ‘most severe point assessment of smoke contamination’ assessment method. Although predicted temperatures are slightly lower than experimental values, FDS temperature slice files can be used at the most severe smoke contaminated point using a 10 °C temperature rise. This 10 °C threshold matches the criterion proposed in the previous experimental research. On the basis of the comparisons for the height of smoke contamination, the simulation results generally match a previously proposed equation for the height of smoke contamination above a balcony spill plume. Copyright © 2012 John Wiley & Sons, Ltd.