The principal dimensions of cyclone separators for emergency response systems have been optimized by determination of the gas loading capacity for geometrically similar cyclones of 290 and 1000 mm diameter. For the experiments, separators made of Plexiglas with top or bottom mounted inlet tubes, with varying feed diameters and top and exit geometries. Moreover, the properties of the liquid in the binary mixture to be removed were also changed. For scale-up the gas volume flow density in the deflecting apron should be limited. Overall the measurements have shown that the optimized equipment is equally suited for removal of aqueous, viscous, and foaming media. The flows encountered in emergency blow-down of reactors can therefore be reliably separated. Compared to the recommendations given in the literature, significantly smaller equipment is required for the same separation performance.