Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 10 1 2018 02 06 19 32 EN HAMID SARKHEIL Faculty Member of Department of Human Environment, College of Environment, Karaj, Iran YOUSEF AZIMI Faculty Member of Department of Human Environment, College of Environment, Karaj, Iran SHAHROKH RAHBARI MSc Student in Chemical Engineering-HSE, Department of Human Environment, College of Environment, Karaj, Iran JAVAD TAVAKOLI MSc Student in Chemical Engineering-HSE, Department of Human Environment, College of Environment, Karaj, Iran PAYAM SHAYAN FARD MSc Student in Chemical Engineering-HSE, Department of Human Environment, College of Environment, Karaj, Iran 2017 10 13 2017 12 18 Inherently Safer Design (ISD) is served as an important and crucial step for Industrial Safety Management Systems. It is simpler, cheaper, and more efficient to eliminate and/or reduce inherent hazards. However, uncertainty, relativity, ambiguousness and quality/quantity transformations disrupt the implementation of ISD. As advantages of fuzzy reasoning, naming problems can be resolved in order to have a justified and sophisticated decision making about Inherently Safer Design Assessment. Accordingly in this paper, ISD four principles: 1.Elimination/Substitution, 2.Minimization, 3.Moderation and 4.Simplification enter the Fuzzy Mamdani system: Fuzzy ISD Index (FISDI) to accomplish Fuzzy Inherently Safer Design Assessment. Inputs and output of the FISDI range from 0 to 100 and are categorized in 5 triangular membership functions. The proposed FISDI is applied for acetic acid production unit. The unit is divided into 7 zones, the 4 principle based checklist is provided for each zone and the FISDI is computed for each zone, then the total FISDI is computed for the unit. The results show that the minimum, maximum and total FISDIs equal to 29, 72 and 45.1 correspondingly. The total plant FISDI data is compared to the classic ISDI. The cross validation accomplished via CFtool in MatLab presents the mean slope of 0.7181 and mean R2=0.7885 which is a justified curve fitting within the scope of the study philosophy_70% of the ISD. The FISDI mainly underestimates the aggregative ISDI. It is noted that the most conformed and the least conformed zone cross validations are determined as Zone 4 and Zone 7 respectively. https://ijoh.tums.ac.ir/index.php/ijoh/article/view/316 https://ijoh.tums.ac.ir/index.php/ijoh/article/download/316/466