A consequence based approach to the quantitative assessment of inherent safety

Abstract

AbstractThe availability of inherent safety drivers for early process design is a critical issue for the further development of the chemical and process industry. In this study, a consequence‐based method for the inherent safety assessment of process alternatives was developed. Key performance indicators (KPIs) for inherent safety were defined and a procedure for their quantitative assessment was developed. A specific equipment classification and the related failure modes were identified, in order to define the potential accidental scenarios associated to each process unit. Rules for the calculation, by physical model runs, of the damage distances for conventional effects were also defined. Credit factors to account for the safety score of the different equipment classes were introduced. KPIs were defined by the combination of the expected damage distances and of credit factors. The methodology was demonstrated through a case study, and provided useful results both for the identification of safety critical units, and for the assessment of the inherent safety of alternative processes. The comparison of the results with those obtained from other literature methods for inherent safety assessment showed that the KPIs introduced allowed considering the hazards coming from auxiliary equipment, that are often overlooked in conventional inherent safety assessment methods. © 2007 American Institute of Chemical Engineers AIChE J, 2007