FMEA, HAZID, and ontologies

Abstract

This chapter is inspired by two sources Trammell and Davis work on a fusion of HazOp and FMEA and extremely simple FMEA used by Airbus in the initial development phases. We discuss the use of ontologies to support efficient FMEA and HazId. The chapter starts with a discussion of FMEA and especially on the use of generic failure modes. In addition we also give a short introduction to HazId. After the introduction to FMEA we discuss the relationship between a control systems FMEA and the systems environment how does a failure propagate to the environment to create harm. Here we also discuss the important concepts of generic fault trees and hazard lists, both heavily used in industry which can be used to study how control systems failures propagate to the control systems environment. We then proceed by giving a short introduction to ontologies and how to create them. We show two examples ontologies for a general control loop and for a simplified steam boiler. The chapter ends with a short discussion on what should be done by computers, using ontologies and computer programs, and what should be left to humans.