The flow rate in thermal plumes are influenced by many factors. Influence by enclosing walls is one of them. This article presents simple symmetry considerations to calculate the flow rate in such flows, and they are experimentally verified as regards wall plumes. When the flow takes place near to enclosing walls the entrainment is influenced and a reduction of the flow rate is observed. For displacement ventilation this means a reduction of the stipulated necessary ventilating air flow rate when an air quality based design method is used.

Inter-zone convection affects the general movements of air in a building and must be evaluated for accurate thermal zones heat and mass balance. The paper presents results of an experimental study of convective heat transfers caused by temperature difference between two zones connected by an opening of height 2. 05 m and varying width. Experiments were carried out in a full scale calorimetric chamber (5.5 m x 2.5 m x 2.5 m). Temperature differences were maintained by two active vertical walls locatedon either side of the doorway.