Analytic Hierarchy Process (AHP) is one of the techniques commonly used for prioritizing different alternatives, by using complex criteria. In real applications, conventional AHP assumes the expert judgment as it is exact and use crisp number leading to inconsideration of the uncertainty that came from linguistic variable. Fuzzy logic deals with situations which are vague or unwell defined and gives a quantify value. In this study a comparison is made between traditional AHP and fuzzy AHP by taking a case of selecting an effective oil refinery. The selection is conducted using system effectiveness as a criterion. The two approaches have been compared on the same hierarchy structure and criteria set and the result show that in both case dual drum scheme (DDS) has the highest priority but different value that is 0.51 and 0.36 for AHP and FAHP respectively which shows that if the expert opinion is certain AHP should be used if not FAHP should be preferred. © 2014 Owned by the authors, published by EDP Sciences.