API 570 Integrity Assessment of Underground (UG) and Aboveground (AG) - Raw Water Pipelines

Project Challenge 

Managing the integrity of more than 24 underground and aboveground raw water pipeline stations across Chonburi, Rayong, and Chachoengsao provinces. The objective was to detect coating damage, corrosion, and component abnormalities at an early stage while developing a consolidated Route-Based Integrity Baseline to support long-term inspection and maintenance planning across a complex pipeline network.

Project Details 

• Location: Thailand (Chonburi, Rayong, and Chachoengsao)  
• Asset Type: UG/AG Raw Water Pipeline Systems  
• Reference Standard: API 570  
• Inspection Methods: Visual Testing (VT) and Ultrasonic Thickness Measurement (UTM)  
• Inspection Scope: Multiple pipeline routes and more than 24 inspection stations  
• Assessment Scope: Thickness Evaluation, Corrosion Assessment, and Remaining Life Evaluation  
• Monitoring Basis: 10 years  

Engineering Inspection Approach 

Rather than performing isolated point inspections, Dexon implemented a route-based integrity assessment approach, integrating inspection data from multiple routes and stations into a unified overview of the pipeline network to establish a long-term Pipeline Integrity Baseline. 

Engineering teams conducted systematic inspections in accordance with API 570 using VT and UTM to assess coating condition, corrosion, fittings, and pipe wall thickness at designated Thickness Measurement Locations (TMLs). Minimum required thickness and remaining life calculations were also performed for each inspection location. 

A key advantage of the project was the evaluation of data under both design pressure and operating pressure conditions, providing the client with a more accurate and practical engineering perspective. This approach enabled more effective integrity and maintenance planning compared to conventional inspection methods that rely solely on conservative design assumptions. 

Project Conclusion 

Inspection results showed that most pipeline sections remained suitable for continued operation. Key findings included coating degradation, localized corrosion, component damage, as well as concrete cracking and water seepage in certain areas, while the majority of wall thickness readings remained within acceptable limits. 

Following completion of the inspection campaign, Dexon delivered a consolidated route-based integrity baseline report and a defensible maintenance plan to support future monitoring, preventive maintenance, and long-term pipeline integrity management in accordance with API 570.