Fault tree analysis process deviation

HAZOP and What-If reviews are two of the most common petrochemical industry qualitative methods used to conduct process hazard analyses. Up to 80% of a company s process hazard analyses may consist of HAZOP and What-If reviews with the remainder 20% from Checklist, Fault Tree Analysis, Event Tree, Failure Mode and Effects Analysis, etc. An experienced review team can use the analysis to generate possible deviations from design, construction, modification, and operating intent that define potential consequences. These consequences can then be prevented or mitigated by the application of the appropriate safeguards. 

This paper presents a new approach based on a combination of traditional predictive modelling and event/fault tree analysis techniques, which allows representing at the same time evolution of hazards and normal and abnormal (i.e. failures) performance of safety measures, e.g. variations of process parameters, analysis and inspections, through the food chain for a better estimation of the real impact of such deviations/failures on consumer health. 

Do not hesitate to combine some of these tools. For example, when doing a hazard analysis or HAZOP, add a hnman factors analysis (as a subset of the overall hazard analysis) if hnman operators play a significant role. Or, if the HAZOP has identified particularly dangerous deviations of the process resulting from a failure in the system, do an FMEA or fault tree analysis of just that critical subsystan. 

---