Development and application of fire & explosion risk index methods to chemical process plants

Fire and explosion risk evaluation in the industrial context is a fundamental tool for work owners and safety manager to individuate critical scenario and issues related to fire and explosion in industrial facilities and sites. The primary objective of the risk evaluation is the definition of possible accident scenarios, their likelihood and consequences concerning damages to people and facilities, as to define an adequate fire strategy and preventive-protection measures. In this work, three real accidents were tested with three real fire and explosion risk evaluation methods, among the most adopted worldwide: F&EI “Fire and Explosion Index, by DOW Chemical Company; The Mond Index, by Imperial Chemical Industries; Safety Weighted Hazard Index (SW&HI), by Khan, Husain, Abbasi (2001). All these methodologies could be classified among semi-quantitative index methods, and their outputs are quantitative values (indexes) which indicate to analysts the most hazardous units or processes and help to define priorities on protection system implementation. A new index, incorporating the incomes of the three methods adopted is proposed in this paper. A sensitivity analysis was also performed, as to investigate whether operating conditions or peculiar characteristics of substances involved in processes has the more significant influence on the risk evaluation, according to the method adopted. This work has also posed the basis to develop a novel method, derived mainly from the SW&HI methodology: this will apply to a wide range of industrial facilities and incorporate relevant features of previous methodologies attempting to eliminate critical points and issues of former methods.