Development of a new index for assessing the inherent safety level of chemical processes using a multi-criteria fuzzy decision-making approach

Estimating and evaluating the inherent safety of processes pose a significant challenge in the field of inherent safety. Indicators are commonly employed tools to address this challenge. However, one of the weaknesses of risk-based indicators is their assumption of equal weight and importance for all indicators, despite the fact that the impact of each indicator may vary. This study aimed to investigate whether assigning weights to indicators can enhance the performance of inherent safety indices. To achieve this objective, all indicators that influence inherent safety were identified through systematic literature review and expert interviews. Subsequently, the final weights of these indicators were determined using multicriteria decision-making methods such as BWM, DEMATEL, and fuzzy ANP. By integrating these indicators, a Weighted Inherent Safety Index (WISI) was developed, accompanied by two subsidiary inherent safety indices: process inherent safety (consisting of 5 indicators) and chemical material inherent safety (consisting of 9 indicators). The WISI index serves as a quantitative measure to assess various synthesis routes of a chemical substance and determine the safer option during the conceptual design phase. In a case study, the production process of methyl methacrylate involving 6 different synthesis routes was selected, and the WISI index was applied to validate its effectiveness. Overall, this approach introduces a novel perspective to enhance the performance of inherent safety indices by assigning appropriate weights to indicators, thereby promoting a more comprehensive evaluation of process safety.