Trial of the “hazid” Tool for Computer-based Hazop Emulation on a Medium-sized Industrial Plant

The HAZID knowledge-based system was developed as part of the EC-funded “STOPHAZ” project, whose brief was to investigate the use of software tools for improving safety in chemical process plants. HAZID models the behaviour of a plant qualitatively, so that the potential hazards of equipment failures can be detected. The models in HAZID are based around the signed directed graph, and hazard identification is driven by a systematic HAZOP-style examination of the causes of all process variable deviations in the model. The potential causes are found by considering all possible fault propagation paths in the plant model being considered, using exhaustive graph search techniques.