This work presents an experimental study of a pressure swing adsorption(PSA) unit running a traditional four-step cycle and a cycle with pressure equalization step for oxygen sepqration from air using a molecular sieve 5A. Due to its complicated nature and multiple decision parameters including plant dimensionality and operation conditions, the design of PSA process is not a trivial task. In this paper, we attempt to obtain the simple general rules for PSA process design. The results of a 4-step PSA experiments are compared with a cycle with pressure equalization step. The optimum operating conditions were observed for given oxygen purity.