## 2 The Process Plant Inspection and Maintenance System
### Improve TAM Efficiency with the Risk-Based Inspection Method  
Various methodologies and approaches have been explored to enhance the efficiency and effectiveness of TAM to minimize downtime, reduce costs, and optimize asset management. [PERSON] [58] interviewed TAM experts and leveraged risk-based identification from historical data to enhance the TAM interval and reduce its duration. Defective parts found during turnaround execution pose challenges, necessitating the rapid arrangement of human resources, spare parts, and logistics. An RBI and decision-making model were formulated to mitigate the turnaround delays caused by such contingencies. This model aims to strategically shift maintenance activities to routine schedules while addressing high-risk units during shutdowns. The implementation of this model yielded promising results: a substantial reduction in TAM duration from 30 to 21 days, attesting to the efficacy of risk-based strategies in bolstering turnaround efficiency [59].  
[PERSON] [60] highlighted the benefits of RBI for assessing aboveground storage tanks and process piping in petrochemical plants. Unlike traditional remaining life calculations, this approach focuses on the risk, incident consequences, and probability. RBI assessments prioritize high-risk components by optimizing inspection resources, maximizing efficiency, and ensuring resource allocation.  
Building upon this risk-based paradigm, researchers have sought to refine the maintenance schedules for plant heat exchangers [36; 61]. By evaluating factors such as vibration, fouling, corrosion, and other failure modes, this approach aimed to extend TAM intervals while minimizing the maintenance duration. The advantages of this strategy include reduced downtime, increased plant reliability, and cost savings.  
[PERSON] et al. [11] applied a framework rooted in RBI to optimize the TAM for pressure drums. By balancing the TAM interval against risk exposure, this study aimed to determine an optimal interval that minimizes downtime and maintenance costs without compromising safety.  
[PERSON] et al. [62] proposed a comprehensive methodology to curtail TAM duration in four steps: selecting noncritical equipment for standard maintenance, applying RBI to critical static equipment, utilizing risk-based failure analysis for rotating equipment, and generating probability failure distributions to fine-tune the TAM plan.  
Acknowledging the dual nature of plant shutdowns and reducing operational risk while potentially generating new risks, [PERSON] et al. [63] examined human errors introduced during shutdowns. Using maintenance optimization and RBI, they strived to define optimal shutdown intervals that balanced maintenance needs with the associated risks.  
[PERSON] et al. [64] conducted a systematic assessment focusing on equipment classification and failure modes. The vast amount of piping equipment used in refining and processing plants poses management challenges, emphasizing the need for structured maintenance strategies. Metal loss due to corrosion is a primary failure mode in carbon steel and stainless steel piping systems, although stainless steel has higher corrosion resistance [65], prompting the application of RBI methods to assess failure consequences and probabilities, as recommended by the American Petroleum Institute (API).  
These studies reflect a concerted endeavor to revolutionize TAM practices, leveraging risk-based insights to fine-tune intervals, durations, and strategies, fostering enhanced efficiency, resource allocation, and asset management.