Risk-Based Strategies for the Next Generation of Maintenance and Inspection Programs

The maritime industry has seen an ever-increasing interest in applying risk-based approaches to better manage the integrity of ships and offshore units in service. The recent initiatives related to IMO in setting Goal Based Standards will also be reflected in justification of maintenance and inspection regimes for marine assets from a performance based standpoint. The development of risk-based strategies for the next generation of maintenance and inspection programs for various ship includes the application of Reliability-Centered Maintenance (RCM) for machinery systems and Risk-Based Inspection (RBI) for hull structures and fixed equipment systems. By applying RCM principles, an operator can improve the reliability of its vessels' machinery system. Risk assessment techniques (FMECA) and RCM analysis are used to determine relevant failure modes and equipment criticality. These inputs provide a process feed for optimization of maintenance tasks for maximum uptime. Further, spares management can be optimized using the RCM process. A sustainment process is also discussed so the operator can keep preventative maintenance tasks current as the system ages, new failure modes are identified, or system modification occur. RBI inspection planning includes risk assessment coupled with the understanding of applicable degradation mechanisms and consequence of failures in the structure in order to develop an inspection program for the asset. Structural analysis plays an important role in this process. For structures, analysis data generated as part of the design process is used to predict the likelihood of failure and account for the degradation that structures inevitably suffer. Combined with an assessment of consequence of failure, structure is risk ranked, inspection methods and frequencies optimized, and then aggregated into an RBI plan. Hence, this process can be regarded as a vehicle for incorporating design information in the inspection process in an integrated way. This represents a significant improvement in integrity management (IM) approach over traditional methods where there is little, if any, interaction between the design and in-service phases of the life of the asset. Further, targeted inspection and data collection of asset health for critical areas within the hull leads to risk reduction overall.