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HAZOPExpert: an expert system for automating HAZOP analysis.

Vaidhyanathan R; Venkatasubramanian V; Dyke FT
Process Saf Prog 1996 Jan; 15(2):80-88
A system for automating hazard and operability (HAZOP) analyses was discussed and applied to a sour water stripper operation as an example. HAZOP is a technique developed to identify and mitigate potential process hazards in the chemical industry. The basic principle of the procedure is that hazards arise in a facility due to deviations from the design or as a result of abnormal behavior in the processes. In a HAZOP analysis, process piping and instrumentation designs (PIDS) are systematically examined by a team of experts to identify abnormal causes and adverse consequences that could occur for all possible deviations from normal operation at the facility. In order to cover all possible malfunctions in a facility, the process deviations to be included in the analysis are generated by systematically applying guide words such as NONE, MORE OF, LESS THAN, or OTHER THAN. A HAZOP analysis is a labor intensive, time consuming, and expensive process that requires specialized knowledge; this arises from the fact that the HAZOP team cannot afford to overlook even the most routine causes and consequences that can occur. A typical HAZOP analysis can require about 1 to 8 weeks to perform at a cost of about 10,000 dollars per week. To reduce the amount of time, effort, and costs associated with performing a HAZOP analysis an expert system for automating HAZOP analyses (HAZOPExpert) has been developed. HAZOPExpert is based on separating the knowledge required to perform a HAZOP analyses into two components: process/specific and process/general knowledge. Each component uses generic HAZOP models of process units. The process/specific knowledge component consists of information about the materials used in the processes, their corrosivity, flammability, volatility, and other properties and the PIDS of the facility. The process/general knowledge consists of HAZOP digraph models of the process units, which are qualitative causal models developed specifically for hazard identification. The HAZOPExpert system was illustrated by applying it to a sour water stripping facility. A conventional HAZOP analysis found 32 abnormal causes and 32 potential adverse consequences at the facility. HAZOPExpert found all of these plus a number that were missed by the HAZOP analysis. This was due to the fact that the HAZOPExpert system is more thorough than the HAZOP system and always considers the worst case scenarios.
NIOSH-Publication; NIOSH-Grant; Grants-other; Risk-analysis; Failure-analysis; Industrial-processes; Chemical-manufacturing-industry; Industrial-safety; Occupational-hazards; Industrial-design; Case-studies
Chemical Engineering Purdue University West Lafayette, IN 47907-1283
Publication Date
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Journal Article
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Other Occupational Concerns; Grants-other
Source Name
Process Safety Progress
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Purdue University West Lafayette, West Lafayette, Indiana
Page last reviewed: October 26, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division