Index major equipment design

Edwards and Lawrence (1993) have developed a Prototype Index of Inherent Safety (PIIS) for process design. The inherent safety index is intended for analysing the choice of process route i.e. the raw materials used and the sequence of the reaction steps. This method is very reaction oriented and does not consider properly the other parts of the process even they usually represent the majority of equipment. 

Identification can be as simple as asking what-iP questions at design reviews. It can also involve the use of a checklist outlining the normal process hazards associated with a specific piece of equipment. The major weakness of the latter approach is that items not on the checklist can easily be overlooked. The more formalized hazard-assessment techniques include, but are not limited to, hazard and operability study (HAZOP), fault-tree analysis (FTA), failure mode-and-effect analysis (FMEA), safety indexes, and safety audits. 

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