In this study, we assess the impacts of RE principles on HSEE factors in a large
petrochemical plant. For this purpose, standard questionnaires are designed according to experts’
opinions to collect the required data. In the process of designing questionnaires, the concept of
Z-numbers is taken into account. This concept is used for two reasons: 1) it is able to handle the
uncertainty and vagueness of information in realistic situations, 2) the required data in this study
are collected from a real system, and therefore it seems rational to take into account the
reliability of the data. The concept of Z-numbers is integrated with FCM and a new method
named Z-number cognitive map is proposed. In the following sections, the concept of Z-numbers
and FCM are described.
3. Methodology
In this study, the concept of Z-numbers and FCM are integrated to propose a new method in
order to evaluate the impacts of RE principles on HSEE factors in a large petrochemical plant
located in Iran. The concept of Z-numbers is used because the reliability of the data is taken into
account through this concept and thus it leads to more realistic results than fuzzy logic (Zadeh,
2011). The main steps of the proposed method are as follows:
• Step 1: Designing and distributing valid questionnaires
The structure of questionnaires distributed among employees of the petrochemical plant, is
defined according to opinions of ten experts. The experts containing two academic experts and
eight senior managers from HSE department, control room, operational department and
administrative division of the petrochemical plant. The questionnaire undergoes a validation
procedure to make sure that it accurately measures what it aims to do, regardless of the
responder. Valid questionnaire helps to collect better quality data and information with high
comparability which reduces the effort and increase the credibility of data