Integration of interlock system analysis with automated HAZOP analysis

The paper details the integration of a method for the analysis of interlock systems with a software support system for HAZOP analysis. The proposed software aims to enhance the potential of HAZOP in terms of depth and ef®ciency of the analysis. This enhancement is reached through the continuation of the hazard and operability analysis, limited to a group of events which may hold high risks for the plant and/or surrounding environment. The analysis technique of the emergency interlock systems and other plant protection measures proposed by the Center for Chemical Process Safety (CCPS) of the American Institution of Chemical Engineers (AIChE) has been assumed as a starting point. The system carries out interactively HAZOP analysis of a plant and identi®es the presence of possible interlock actions through the analysis of the plant P & I diagram and then visualises the individual interlock systems starting the design phase in which it is possible to analyse and change interactively the single interlocks systems, in order to obtain the required reliability. q 2001 Elsevier Science Ltd. All rights reserved.