Risk-Based Inspection Plan for a Tanker Truck Loading System in the Chilean Chemical Industry

Abstract

This paper presents a case study conducted in a chemical company located in the Bay of Quintero (Chile), where a Risk-Based Inspection (RBI) plan was designed for a new tanker truck loading system composed of piping networks divided into 19 circuits. To quantify risk, the quantitative methodology from the recommended practices API RP 580 and API RP 581 was applied. The probability of failure was evaluated using a generic failure frequency, a damage factor associated with generalized wall thinning, and a management factor, while the consequences of failure (safety, environmental, and economic) were estimated through a Level 1 analysis using representative process fluids.

The results indicate a probability of failure on the order of 1.39E-06 failures per year and an estimated financial consequence of USD 471,715, which translates into an annual risk close to USD 0.7, classified as low risk according to the criteria of API RP 581. Therefore, no additional specific mitigation measures are recommended. Based on these results, a condition-based inspection policy aligned with API 570 is proposed. This policy defines nominal, required, and alarm thicknesses for each circuit, identifies Condition Monitoring Locations (CMLs) for ultrasonic thickness measurements, and establishes a base inspection interval not exceeding three years, aiming to ensure the mechanical integrity of the system and the safe and efficient continuity of loading operations.