Composite Repair to Restore In-Plant Piping - A Case Study

Introduction

Restoring process piping within a short time frame requires an innovative approach. In recent cases, due to time limitations and the desired reliability and quality levels, a repair using composite materials proved to be the most feasible option. The utilization of the composite materials repair approach was successful and enabled a quick return to operations. A team of subject matter experts carried out a full assessment on all affected metallic piping circuits and special consideration was given to the repair time frame. Using API 579-FFS assessment criteria, we evaluated all types of damage that had occurred, including dents, gouges, and fire exposure. The piping system repair options were classified into three main categories: piping replacement, metallic, and non-metallic repairs. Composite material repairs resulted in piping system life-extensions with the desired level of reliability. A more in depth explanation of our experience is provided below.  

Background of the Incident 

A process safety incident in an operating facility damaged nearby equipment and piping systems, and led to a loss of production. The production had to be restored in the shortest possible time. A systematic piping rehabilitation strategy was deployed to restore the plant in the specified time frame. To ascertain the integrity of the piping for continuous operation, the team performed fitness-for-service (FFS) assessments as prescribed by API 579/FFS-1^[1], ASME PCC-2 ^[2], and ISO 24817 ^[3]. These standards were used to determine the remaining life of the damaged piping sections. The assessment began by evaluating four different types of damage: dents, gouges, through-wall defects, and fire exposure. The assessment was used to decide whether to keep, repair, or replace the damaged sections of the piping. Therefore, the piping systems were classified into three main categories: spool replacement, metallic, or composite repair. 

History of Composite Materials Repair Application

Properly designed and installed metallic pipelines and piping are one of the safest, most reliable ways to transport oil and gas fluids. There are approximately 1.7 million kilometers of pipeline networks around the globe carrying hydrocarbon products every day ^[4]. Repairing them, either by welding, sleeve welding or spool replacement, requires equipment shutdown and other related hot work preparation activities ^{[5], [6]}. Even though fiber-reinforced polymer (FRP) composite materials have been used for pipelines since the 1980s,  interest in using composite materials as a repair method has increased recently because of their relative ease of application and potential cost savings when compared to traditional repair methods ^{[4], [7]–[15]}.  It is estimated that repair of defective piping using composites is 24% and 73% less costly than welded sleeve and section replacement, respectively ^[4].