The course of explosions in vented reaction vessels is a complex process with interaction of the combustion reaction and the flow in the vessel, especially during venting. A method for describing such processes is the computational fluid dynamics. In order to increase the number of values for the validation of such a model, experiments have been performed in two test equipment which have been manufactured especially for the tests. The main advantage of these tests in comparison to many others is the simultaneous measurement of pressure, flame propagation and flow velocity during the explosions. In the first equipment (variable volume from 2 to 59 L) the influence of vessel volume, length-to-diameter-ratio, venting diameter and activation pressure of the venting device on the course of an explosion has been examined for a propane/air/nitrogen-mixture. The second equipment had a volume of approx. 100 L. It was developed particularly for the determination of the influence of pre-ignition turbulence on the course of vented propane/air/nitrogen and maize starch/air-mixtures. The main results of the tests were a minor influence of venting introduced turbulence on the maximum rate of pressure rise and the reduced explosion pressure and a strong influence of the pre-ignition turbulence on these parameters especially for low activation pressures of the venting device. For high activation pressures the influence was negligible. First simulations with an initially quiescent mixture gave realistic pressure histories and showed a quite good correlation with the experiments. The comparison between experiments and venting areas, which have been calculated with an empirical method taken from the future norm for gas explosion venting devices, gave in all cases a sufficient dimensioning.