An index-based approach for the evaluation of inherent safety in process plant design

An index-based method for estimating the inherent safety in conceptual process design has been presented. The method is required, since inherent safety should be considered in the early phases of design when the major decisions on the chemical process are made. The total index is divided into chemical and process inherent safety indices. The former is composed of subindices for reaction heats, flammability, explosiveness, toxicity, corrosiveness and chemical interaction. The latter is derived from the subindices for inventory, process temperature, pressure, and the safety of the equipment and process structure. The equipment safety subindex was developed based on accident statistics and layout data. The subindex for process structure is evaluated by case-based reasoning on a database of good and bad design cases, i.e. experience-based information on recommended process configurations and accident data.