Assessment and Rehabilitation of Corrosion Under Pipe Supports (Cups): Development And Validation Of A Structured Integrity Decision Model

Abstract

Corrosion Under Pipe Support (CUPS) poses a significant threat to the integrity of offshore piping systems primarily due to harsh environmental conditions. This study investigates CUPS in offshore platforms, focusing on a comprehensive approach that includes inspection, degradation analysis, rehabilitation, and preventive strategies. An 8-inch diameter process piping was thoroughly inspected, revealing extensive wall thickness loss with the remaining thickness falling below critical thresholds. A detailed Fitness-for-Service (FFS) assessment, conducted according to Part 4 and Part 5 Level 1 and 2 criteria, did not meet the stringent conditions required for acceptance. The Maximum Allowable Working Pressure (MAWP) was found to be substantially lower than the design pressure, indicating severe operational risks.  To address these issues, rehabilitation methods such as the installation of full-encirclement steel reinforcing sleeves and the adoption of high-strength thermoplastic I-Rods were evaluated. These methods aim to restore structural integrity and prevent future corrosion. The study emphasises the importance of implementing robust inspection protocols, timely maintenance, and proactive preventive measures. By adopting these strategies, the reliability and safety of offshore piping systems can be significantly enhanced, mitigating the risks associated with CUPS. The findings highlight the critical need for ongoing monitoring, regular maintenance, and the use of advanced materials and design strategies to extend the lifespan and ensure the safe operation of offshore piping infrastructure.