Safety Critical Elements in Asset Management

Safety critical elements (SCEs) are those systems and components (e.g. hardware, software, procedures etc.) that are designed to prevent, control, mitigate or respond to a major accident event (MAE) that could lead to injury or death. The effective identification, design, installation, operation and maintenance of SCEs presents one of the most challenging aspects of modern asset management especially when the effectiveness of the SCE must be achieved and maintained over an extended time period. SCEs require high levels of equipment design and implementation, high levels of reliability, high levels of management control over extended time periods and high levels of skill and work performance. Identification of SCEs must be based on a formal assessment system that is both practical and credible. Once identified, SCEs must have detailed performance standards, critical function tests, maintenance plans, documentation etc. all of which must integrate with other maintenance and operations tasks conducted for non-safety critical reasons (e.g. economic risk criteria). Unlike maintenance activities on non-safety critical equipment where we wish to optimise on the basis of reliability/availability or cost, with SCEs we wish to prevent the ‘first event’. This paper looks at the challenges presented by SCEs and what is required of the asset management system if SCEs are to perform effectively over the life of the plant.