In general, explosion hazards are a well-known risk in the process industries. However, the hazard of dust explosions is still underestimated in certain industrial areas. A clear understanding of the reaction mechanisms is crucial for the prediction of dust explosions. Research on dust explosion behaviour under non-atmospheric conditions leads to results allowing a more detailed investigation of influencing parameters on explosion reactions in general. For this thesis the influence of reduced pressure conditions as well as the influence of different inert gases on flame propagation has been studied. For this purpose, experimental devices to measure flame velocity were developed and experiments were carried out at different dust concentrations, at varying oxygen levels and at pressures down to 200 mbar. While flame velocity showed a linear decrease with decreasing oxygen concentrations, velocity at reduced pressure conditions reached its maximum below atmospheric conditions. The mechanisms of ignition were also of special interest with fundamental deviations from normal conditions observed.