5. Risk- and Condition-Based Maintenance

Condition-based maintenance (CBM) strategies have increased in recognition over the last decades, and continues to do so with an internationalized market and cheaper sensor technology. CBM is in many cases the most effective approach to maintenance, considering risk, resource use, sustainability, safety and cost. Thus, CBM is often feasible both from a life-cycle cost (LCC) perspective and a life cycle analysis (LCA) perspective. In this chapter, we will study risk-based and condition-based maintenance from a maintenance and reliability perspective. After a brief background, we will discuss the necessary conditions for CBM to be a feasible strategy for optimized usage of equipment. On the operational level, CBM can be on schedule, on request or on a continuous monitoring basis. Thus, the technologies used for CBM can broadly be divided into continuous monitoring, which often is simply called condition monitoring, and into non-destructive testing (NDT), for periodic inspections. Therefore, two sections are dedicated to condition monitoring and NDT. Additional techniques for CBM and risk assessment will be discussed in the section thereafter. Lastly, we will look briefly into the continuously growing topic of prognostics.