Citation

Yazdi M. Int. J. Occup. Safety Ergonomics 2019; 25(4): 551-561.

Affiliation

Department of Industrial Engineering , Eastern Mediterranean University , North Cyprus via Mersin 10, Famagusta , Turkey.

Copyright

(Copyright © 2019, Centralny Instytut Ochrony Pracy - Państwowy Instytut Badawczy, Publisher Informa - Taylor and Francis Group)

DOI

10.1080/10803548.2017.1419654

PMID

29261030

Abstract

Risk graph (RG) is the widely used method to evaluate the safety integrity level (SIL) of safety instrumented systems (SIS). However, the subjective opinion based conventional RGs cannot provide successful results in the problems of risk parameters, such as shortages or lack of data, hence, the output of a conventional approach lacks enough reliability. In this paper, we introduced fuzzy improved risk graph (FIRG), an extension of the fuzzy set theory, to deal with the possible ambiguities during the SIL study and increase the reliability of conventional RGs. In the present study, the levels of consequences defined as linguistic terms were converted into qualitative intervals, therefore, by correlating the proposed approach with the experts' opinions and attributing weights factors, a desired value of SIL was obtained. Further, a practical example of oil and gas refinery was incorporated in this paper to manifest the effectiveness of FIRG over the conventional approach. So the output of this new approach can be compared directly with the quantitative risk assessment techniques to improve the safety performance of industrial systems.

Language: en

Keywords

Chemical plant; Fuzzy set theory; Risk graph method; Safety integrity level