This paper describes the application of a numerical field model to the problem of fire induced flows in rooms. Particular attention is paid to the effect on air entrainment of fire location, and of thermal radiation. The comprehensive set of full scale room fire experiments reported by Steckler et. a1. has been used for comparison with predictions. It is shown for corner fires that in addition to the jet of hot combustion products leaving under the top of a doorway opening, there is, below it, a significant outflow of heated air apparently resulting from the redistribution of energy between hot and cool layers by thermal radiation. A comparison of the predicted doorway flow rates with measurements is shown to be in good agreement.