Practical aspects of applying risk-based approaches in asset management for heat exhangers

Risk-based inspection and maintenance can help to achieve safe and economically viable plant operation by justifying and prioritizing actions, choices and schedules according to the associated risk. To manage the risk, the implemented inspections and maintenance actions aim to limit the probability of failure and its uncertainty. Failure statistics of similar components operating in similar environments may provide fair estimates of the probability of failure, but biased or lacking comparable statistics may require adjustment through additional measurements or expert information. In parallel, inspection and monitoring data can more directly help in assessing the evolution of probability of failure. Presented example is a tubular heat exchanger, with inspection and failure criteria considered for a full life cycle that included multiple inspections by the same inspecting party and equipment. Uneven distribution of in-service wall loss without changes in mechanisms or local loss rates nevertheless required a change of inspection strategy during the life cycle.