UML modelling concepts of HAZOP to enhance the ability to identify emerging risks

Unified Modelling Language (UML) has a graphical notation for 13 different types of diagrams and can be used as a general modelling tool. Well-known examples of diagram types are class diagrams for modelling classes that can be instanced into objects, state machine diagrams for modelling states in systems and activity diagrams for modelling process flows. A literature survey shows that UML has been used to model concepts and methodologies of risk assessment and risk management. One example is the Coras Framework. The international standard CEI IEC 61882 Hazard and operability (HAZOP) studies describes concepts for investigating and detecting possible hazards in systems. In CEI IEC 6882, guide words like ‘More’ and ‘Less’ are applied to system parameters to invoke deviations in the system and assess possible hazards due to the deviation from the design intent. In this paper, we have used UML to model concepts of CEI IEC 61882 Hazards and operability studies. Diagrams of UML were used to show dependencies and relations between parts of the target system and concepts of CEI IEC 61882. Extensions of UML are suggested to better capture and display the concepts of CEI IEC 61882, the results of a HAZOP study and emerging risk. These extensions are referred to as UML for emerging risks (UML-ER).