Determining Integrity Reassessment Intervals Through Corrosion Rate Modeling And Monitoring

Project Categories

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• Direct Assessment
• Internal Corrosion
• External Corrosion
• Integrity Management

Main Objective

The objectives of this program are to develop easy to implement methods based on sound physical principles to estimate (i) external corrosion rates, especially in CP shielded areas and (ii) internal corrosion rates by considering pipeline-relevant factors for gas and liquid lines. The inputs to these models will be information obtained by pipeline companies during direct assessment or other base-line integrity assessment process. A further objective is to validate these methods using a combination of field and laboratory data.

Public Abstract

One of the critical elements in implementing a continuous integrity management process, as required by pipeline safety regulations, is the assessment of the location and size of defects (internal and external) in the pipe. Because these defects could grow with time through corrosion processes, it is necessary to calculate the corrosion growth rate of flaws in order to estimate the time period for subsequent integrity assessment. Existing methods for estimating defect growth rate are not applicable under all circumstances, especially in cases where in-line inspection cannot be performed. This proposal addresses two challenging aspects of calculating corrosion rates: (i) external corrosion rates under CP shielded areas and (ii) internal corrosion rates as a function of pipeline operating conditions (e.g., gas quality). The project will model the external and internal corrosion using sophisticated computer software, TECTRAN. It will validate the calculated corrosion rates through field data obtained by pipeline companies as well as through laboratory studies. Southwest Research Institute is supported in this project by Pipeline Research Council International (PRCI), Gaz de France, Southern California Gas, and Valero Energy. It is estimated that the more accurate corrosion rate estimation methods may save the pipeline companies more than $100 Million per year through reduced maintenance costs and accident avoidance costs.

Status History

1/15/2006 Draft Final Report approved by J.Merritt. ml
Haen't received an updated report without the "DRAFT"