The liquid holdup, pressure drop, and mass transfer efficiency of sieve trays for the steam stripping trace toluene from water were measured from a 4-ft column at atmospheric pressure. The measured data were then compared with predictions from often-used models. It was found that the published efficiency models whether based on distillation or stripping systems are unable to predict both the trend and value of the measured efficiency. Since the 4-ft column owned by Fractionation research, Inc. (FRI) can be considered as an industrial-scale column, the measured efficiency provides immediate design guidelines for such services.