In this blog post, Dr Calum Powrie, Chief Consultant, Safety Case Service Lead at CRA discusses safety case development, outlining the process to deliver a good safety case.
For any facility (e.g, nuclear, aviation, rail, oil and gas) that can involve potentially large consequences of failure, the development and implementation of a safety case is vital to ensure that for all lifecycle phases (design, construction, commissioning, operation and decommissioning), risks are maintained As Low As Reasonably Practicable (ALARP).
It is essential that a safety case can be readily understood and used by those with direct responsibility for safety. Therefore, a good safety case must communicate a clear and comprehensive argument that any activity on a facility can be undertaken safely. It is also important to note that a high quality safety case, effectively implemented promotes not only a safe plant, but also a profitable plant as the plant will have greater reliability. Thus, the safety case is beneficial to both the business, the operators, general public and the environment.
A “good” safety case is not the result of some mechanical number crunching process, but rather the fruition of considerations and judgements of a good safety case lead, supported by specialists and experts in specific topic areas. There is no definitive step by step route to guaranteed success, rather there is a broad sequence to be considered and it is an integrated and iterative process as the design and safety case matures. That is:
•Fault and Hazard ID
•Assessment of the consequences of the hazards under normal operating conditions and also under fault conditions
•Development of a fault schedule
•Identification of the plant required to protect against the hazards and faults
•Development of an engineering schedule and the substantiation of the plant
•An assessment to confirm that the design of the plant is ALARP
It is vital that throughout the process, the plant design and safety case are developed iteratively together. Safety case development does not lead to design development, nor vice versa. But the safety case can inform design development. It is essential that any safety case arising is visible, comprehensive, easy to understand, accessible and usable by the operator. Similarly the environmental aspects of safety need to be considered in parallel.
The Risk & Safety Forum agenda includes presentations from: EDF Energy, Delft University of Technology and Jacobsen Analytics. Attending the Forum is a fantastic opportunity to hear from industry experts, discuss latest developments and challenges and share best practice with safety case specialist peers.