The results of an experimental study indicating a:significant effect of col
umn diameter on the pressure drop and capacity of corrugated sheet structur
ed packing are presented. The experiments were carried out with Montz-pak B
1-250, using an air/water system at ambient conditions in perspex columns w
ith internal diameters of 0.2 m, 0.45 m, 0.8 m and 1.4 m. The results clear
ly show that both the pressure drop increase and capacity decrease become s
ignificant when the column diameter approaches the value equal to that of t
he height of a packing element. This observation suggests that column diame
ter(s) based on small scale data can be too large.