An experimental investigation is conducted to study buoyancy and pressure induced flow of hot gases in vertical shafts as a model of smoke propagation in elevator and ventilation shafts of high-rise buildings due to fires. Various configurations are tested and the inlet conditions are varied over wide ranges. Temperature measurements are taken within the shaft to allow a detailed study of the steady state thermal fields established in the shaft. Results indicate a wall plume as the primary transport mechanism for smoke propagating from the inlet towards the exhaust region. Recirculation and entrainment dominate at high inlet Grashof numbers, while increased inlet Reynolds numbers allow greater mixing in the shaft. The development and stability of these flow patterns and their effects on the smoke behavior are assessed. The results yield the conditions for fastest smoke removal and lowest overall shaft temperatures as a configuration with natural ventilation at the top. Other interesting features and results are obtained on this flow.