delphi fuzzy

Permit to work system  is a formal, documented and written system that aim to control risk of occupations that are considered potentially dangerous. The porpuse of this study was to identify and prioritize the criteria affecting the performance of the permit to work systeam  in an oil refinery.

The present study was designed and implemented in three steps. In the first step, by reviewing previous studies and conducting interviews with experts, the perimarly criteria were identified. In the second step, fuzzy delphi methode was used for determine the final criteria , in this step  opinions of 25 experts on the perimarly criteria were collected and combained . Finally,  fuzzy hierarchical analysis method was used in order to weight and prioritize the identified criteria.

result of Fuzzy Delphi  methode was showed that six criteria,  risk identification and risk assessment, training and competence of individuals, preventive actions , communication, responsibility and coordination as criteria affecting the performance of the permit to work systeam . Prioritization of criteria using fuzzy hierarchical analysis showed that the criterion of responsibility )final weight 0.191( and coordination and communication criteria )final weight 0.134( have the highest and lowest importance among the identification criteria.

In this study, a model of decision making based on Delphi methods and fuzzy hierarchical analysis was introduced to identify the factors affecting the performance of the  permit to work system in an oil refinery.