API NL GAS PIPELINE AT LAMPHUN PROJECT
PIPE-TO-SOIL POTENTIAL TEST
The conclusion of the pipelines is more negative than -700mVCSE, which makes it easier to polarize the pipes to reach the minimum goal of -850mVCSE. The consistent good native potential values indicate that the pipes’ coating is in good condition.
The ON potentials observed at each TP, indicate values more negative than -850mVCSE, which one of the basic criteria of CP as per NACE SP 0169-2013.
The potentials measured of the all the anodes were consistent with the theoretical Magnesium anode potential with respect to CSE. It also indicates that all the anodes are safely installed and no cables were broken during installation.
The inspection shows that at each TP, the CP current per anode is sufficient to protect the both the pipelines at that location. One anode at each TP has been connected to cathodically protect the pipelines. The extra anodes can be used over the period of the pipeline as the pipes’ coating or soil conditions change.
DCVG TEST
The test report shows the ON/OFF potential from the temporary ICCP system set up for DCVG inspection test. During this test, there was no indication of coating breakdown on the two 9.346 km pipelines. A variation in potential signal at each test post is due to the change in soil resistivity.
Description
The cathodic protection current was determined by assuming 0.25% coating breakdown of the 4” pipelines 3,461 km in a soil resistivity 5000 Ohm-cm. The conservative calculations showed that in order to meet the CP current a total of 42 magnesium anodes will be needed. But as an extra precaution, 42 anodes(2 anodes/ TP) were decided to be installed.
Details
- Owner: AIR PRODUCTS INDUSTRY CO.,LTD
- Contractor: KIKUCHI INDUSTRIAL (THAILAND) CO.,LTD
- Sub Contractor: CGL ENGINEERING CO.,LTD
- Location: GAS PIPELINE AT LAMPHUN
- Working Period: 30 Days
Project skills
- Installation complete
- Presentation