Fire and Explosion Index calculation method incorporating classified safety measure credits

• The existing methods for the modification of F&EI for the DOW Guide were analyzed, and found some limitations.
• A new modification method named classified safety measures credit was suggested.
• A case study was taken to compare the results of the different modification methods.

Based on an analysis of two methods for the modification of the F&EI for the DOW Guide, it is found that the effects of safety measures are not classified. Moreover, the efficiency of the measures is magnified to various degrees, as the positive impact of the loss reduction measures are applied to the rate reduction of the intrinsic hazard in the evaluated unit. For this reason, a modification method using classified safety measures is proposed, in which safety measures are classified into process protection measures and loss reduction measures. The calculation of the modified F&EI involves the credit factors of process protection measures, whereas the determination of the maximum probable property damage incorporates the loss reduction measures. This method could provide more reasonable reference data for hazard units because of its more objective and reasonable evaluation results.