This paper presents the results of research into the effects of an air-handling system on fire development in a full-scale prototype building. Two full-scale experiments were conducted; one with the air-handling system operating and one without. The experimental results showed that the operation of the air-handling system significantly speeded up the fire development. A computational fluid dynamics (CFD) model has been applied to these fire scenarios with the same conditions as the experimental set-up. The CFD model provided the predictions of the magnitude and trends for the experimental results.