A petrochemical facility has been experiencing recurring failures in its fiberglass piping Cooling Water (CW) network. With seven failures reported up to 2014 and a recent failure in November 2023, the integrity of the system has come under scrutiny. As the fiberglass piping approaches its 20-year design lifetime, a comprehensive review was initiated to assess the system’s integrity, identify failure causes, and recommend solutions to mitigate future risks. This aim of this project is to examine the challenges faced by the aging CW network and the steps taken to ensure its continued safe operation.
Evaluating Piping Integrity: Key Challenges and Objectives
The primary technical challenge is the recurring failures in the fiberglass piping of the CW network, which is nearing the end of its design lifetime. The specific issues include:
- Multiple failures over the system’s lifespan, with the most recent occurring in November 2023.
- The need to evaluate the system for an extended 30-year design lifetime.
- Ensuring compliance with the latest ISO 14692 standards (2017 edition).
- Addressing potential overstresses and external factors such as soil settlement and excavation impacts.
The review must consider these factors while proposing solutions that maintain system integrity and operational safety.
Evaluating Cooling Water System Integrity
The asset integrity review employed a multi-faceted approach:
- Stress Analysis: The analysis was updated to reflect a 30-year design lifetime, incorporating reduced maximum allowable stress values as per ISO 14692. The system was divided into multiple submodels for detailed analysis.
- Load Case Evaluation: Standard loads (weight, pressure, temperature) and unbalanced surge loads were considered. The analysis included Sustained (SUS) and Operating (OPE/OCC) load cases.
- Site Inspections: Comprehensive on-site evaluations were conducted to assess the condition of existing and new piping, installation quality, and maintenance practices.
- Historical Data Review: Previous failures and mitigation measures were analyzed to understand recurring issues and the effectiveness of past solutions.
- Simulation: The impact of excavation and soil resistance on the CW line was simulated to assess potential risks.
Mitigating Risks in Fiberglass Piping Systems
Based on the analysis, the following solutions were proposed:
- Replace high-stress locations
- Introduce additional manholes at recommended intervals of 250m for easier inspection.
- Implement underground pipeline monitoring adopting Dynaflow’s method statement for assessing pipe sag and ovalization.
- Thoroughly evaluate any incidents near the CW line, especially soil-related issues, involving an FRP specialist.
Conclusion
The asset integrity review of the fiberglass piping in the CW network has revealed that while the system is nearing the end of its design lifetime, it can continue to operate safely with appropriate interventions.
The proposed solutions offer a comprehensive approach to extending the system’s operational life and improving its reliability. By implementing these recommendations, the facility can ensure the continued safe operation of its CW network while minimizing the risk of future failures.
