With the large number of composite repair systems currently available in today's market, it is a challenge for the pipeline industry to determine which repairs systems are best-suited for their particular needs. While regulators and pipeline standards recognize the use of composite materials and several of the current systems have been extensively tested and evaluated, at the present time there are numerous systems that have not been subjected to the same level of scrutiny. Additionally, several pipeline companies were interested in conducting a study to evaluate and confirm the long-term performance of composite repair systems using a testing program involving buried pipe with machined simulated corrosion. For these reasons the current study is being conducted.
The primary focus of this program is to confirm the long-term performance of actual composite repair systems on pipes subjected to in situ service conditions, namely static and cyclic pressures along with cathodic protection. This will be accomplished by conducting long-term testing performance evaluations up to 10 years using current composite repair technologies. During this program the repair system will be charged with repairing corrosion depths of 40, 60, and 75% in 12.75-inch x 0.375-inch, Grade X42 pipes. This study involves ten (10) manufactures and the overall program will involve 165 full-scale pipe samples. Pipes will be repaired, buried, pressurized (including periodic cycling), and removed for burst testing at 1, 2, 3, 5, 7.5, and 10 years as appropriate. A round of burst tests will also be conducted on 30 samples prior to burial and will serve as the baseline measurements. Strain gages will also be installed in the corroded region of each repair and monitored periodically during the testing program.
The primary focus of this program is to catalog and survey the performance of available composite repair systems. The surveying efforts will include two surveys: one for the Users (i.e. pipeline operators), and another for the Manufacturers including their testing results and performance data.
The desired solution from this program is for industry to avoid replacing perfectly good composite repair systems due to a lack of engineering data to support their permanency. This program will also provide a greater understanding about the capabilities and limitations on the long-term use of composite materials to repair high pressure gas and liquid pipelines.