AbstractA relationship has been developed describing quantitatively the factors affecting packed column performance. The relationship, based on the Colburn equation, is proposed within the limits of a consistent flow regime in the liquid phase.Via separation of the effects of packing geometry on diffusion rates and the effect of area variation with flow rate, single phase transfer rates can be obtained from over‐all mass transfer data. The appearance of a maximum in the relationship of HoG vs. G in the range of 60% of flooding is explained by the large increase of the term HoG/ai (∂ai/∂Gm) relative to the term 1/ai (∂HGai/∂Gm). The ammonia‐air‐system behavior is analyzed via this relationship. It is found that the gas phase resistance varies between 72 and 94% of the over‐all resistance as a function of flow rate.