Development of a computer-aided fault tree synthesis methodology for quantitative risk analysis in the chemical process industry

Abstract

There has been growing public concern regarding the threat to people and \nenvironment from industrial activities, thus more rigorous regulations. The investigation \nof almost all the major accidents shows that we could have avoided those tragedies with \neffective risk analysis and safety management programs. High-quality risk analysis is \nabsolutely necessary for sustainable development. \nAs a powerful and systematic tool, fault tree analysis (FTA) has been adapted to \nthe particular need of chemical process quantitative risk analysis (CPQRA) and found \ngreat applications. However, the application of FTA in the chemical process industry \n(CPI) is limited. One major barrier is the manual synthesis of fault trees. It requires a \nthorough understanding of the process and is vulnerable to individual subjectivity. The \nquality of FTA can be highly subjective and variable. \nThe availability of a computer-based FTA methodology will greatly benefit the \nCPI. The primary objective of this research is to develop a computer-aided fault tree \nsynthesis methodology for CPQRA. The central idea is to capture the cause-and-effect \nlogic around each item of equipment directly into mini fault trees. Special fault tree \nmodels have been developed to manage special features. Fault trees created by this \nmethod are expected to be concise. A prototype computer program is provided to \nillustrate the methodology. Ideally, FTA can be standardized through a computer \npackage that reads information contained in process block diagrams and provides \nautomatic aids to assist engineers in generating and analyzing fault trees. \nAnother important issue with regard to QRA is the large uncertainty associated \nwith available failure rate data. In the CPI, the ranges of failure rates observed could be \nquite wide. Traditional reliability studies using point values of failure rates may result in \nmisleading conclusions. This dissertation discusses the uncertainty with failure rate data \nand proposes a procedure to deal with data uncertainty in determining safety integrity \nlevel (SIL) for a safety instrumented system (SIS). Efforts must be carried out to obtain \nmore accurate values of those data that might actually impact the estimation of SIL. This \nprocedure guides process hazard analysts toward a more accurate SIL estimation and \navoids misleading results due to data uncertainty.

Cite this work

No public copy is stored for this record, so only the metadata is cited.

Stored only when both papers are in the corpus — 8 citations exist upstream.

Papers that cite the same references — the relational fallback while embeddings are still backfilling.