Gas rectification columns are a very important part of each onshore plant. Their sudden failures cause huge losses on a daily basis, while fluid leakage can be very dangerous to people and environment. For that reason, the proper design of the column is of huge importance, among the others safety factors as well. In this paper, the wall thickness measure is presented with the aim to calculate corrosion rate and remaining life of rectification columns. The minimum required column wall thickness was calculated according to the most commonly used international standard and the obtained difference was analyzed.