Assessment & Validation of TFI-Identified Anomalies Criteria for Repair and Available Repair Methods

Main Objective

To develop a repair tool kit that will assist pipeline operators in determining available repair methods while defining anomalies in seam welds.

Public Abstract

The objectives of this project are to (1) compile and evaluate the unique properties of early generation pipeline weld seams, (2) compile a catalog of defect types, and (3) develop methods for evaluating seam weld defects to determine whether pipeline integrity has been compromised.

Following this methodology, the proposed work will provide an understanding of the types of defects and mechanical properties of early generation seam welds, and will describe methods for evaluating the severity of seam weld defects. The results will expand the options to use the emerging seam weld inspection technologies.

Seam weld defects are some of the integrity threats that are considered by pipeline operators in the development of integrity management plans. In particular, some early generation seam welds (e.g., prior to about 1970) can be more susceptible to failures because of poor mechanical properties (e.g., low toughness) that result in relatively small tolerable defect sizes (depth and length).

Pipeline operators have typically managed the integrity of early generation seam welds through hydrostatic testing. More recently, in-line inspection (ILI) technologies, especially transverse field inspection (TFI) tools, have emerged as another option to identify seam weld defects that could affect pipeline integrity. However, the methods for evaluating the severity of seam weld defects are still evolving. The current industry practice is to repair any 'crack-like' seam weld defect, rather than following a protocol with formal assessment criteria. This practice has likely resulted in the unnecessary repair of numerous seam weld defects.

Many pipeline operators have difficulty with the interpretation of results presented by ILI vendors. Without a consistent classification method and assessment protocol, the assessment is a very time consuming task. The proposed work will provide an understanding of the types of defects and mechanical properties of early generation seam welds, and will describe methods for evaluating the severity of seam weld defects.

Final Report

Final Report Appendix A: "Catalog of Early Generation Pipe and Weld Properties"

Projno115_Final_Appendix_A_Jan05.pdf (4,424,217 bytes) [View] [Download/Save...]

Final Report Appendix B: "Catalog of Seam Weld Defect Types"

Projno115_Final_Appendix_B_Jan05.pdf (12,787,737 bytes) [View] [Download/Save...]

Final Report: "Early Generation Seam Welds"

Projno115_Final_Jan05.pdf (291,315 bytes) [View] [Download/Save...]

Other Files

Success Story

SuccessDTRS56-03-T-0002.pdf (398,803 bytes) [View] [Download/Save...]