Chapter 37 - Probability- and Risk-Based Inspection Planning

Abstract

This chapter discusses probability- and risk-based inspection planning. Risk assessment can be used as a valuable tool for assigning priorities among inspection and maintenance activities. This chapter shall present the following: concepts of risk-based inspection, reliability-updating theory for probability-based inspection, risk-based inspection examples, and risk-based optimum inspection. It is concluded in this chapter that inspection planning is dependent on the consequences of failure, corrosion rate, ship age, and probability of detection. The “optimum” inspection program should begin with the design of the structure, proceed through the life of the structure, and conclude with its scrapping. The optimum inspection program should include not only the hull structure, but also the structure's equipment and personnel. In general, dimensions of risk can be considered to occur in the categories of personnel, fatalities, impairment, environmental, assets, etc. This chapter discusses reliability-updating theory for probability-based inspection planning. Fatigue failure is defined as the fatigue crack growth reaches the critical size. The methodology presented could be extended to risk-based inspection. The likelihood of failure may be divided into three categories as mentioned in this chapter. The vessel factors can be divided into two categories: design factors and condition/maintenance factors. The “optimum” inspection method can be proactive or reactive. Some general objectives of an inspection data system are described in this chapter, including the collection of inspection data, storage of data, and provide means for logic inspection data management.