Enhancing Direct Assessment with Remote Inspection through Coatings and Buried Regions

Main Objective

The objective of the proposed program is to extend EMAT technology to address two areas of direct assessment and inspection of installed pipelines. One area is the full body inspection of tar coated pipelines for corrosion damage with a minimum of excavation. The other is the measurement of residual stress and plastic strain in pipelines that have been bent or otherwise displaced by movement of the surrounding earth or instability in the soil under pipe supports. Particular emphasis will be placed on non-piggable lines and the use of instrumentation that is suitable for field operation by inspection service providers.

Public Abstract

Electromagnetic Acoustic Transducers (EMATs) offer several features that make them particularly suitable for direct assessment and inspection of operating pipelines in the field. They can launch and detect guided ultrasonic waves in the metal of the pipeline wall through the tar coating as would be required for performing an inspection of a pipeline that has only been partially excavated. By making quantitative measurements of the velocity and attenuation of particular guided wave modes, the presence of residual stress or strain in the steel can be inferred and the loss of acoustic energy by scattering from corroded regions can be detected. The proposal is directed at the development of ultrasonic sensors that can address these two problems associated with direct assessment of installed pipelines. Thus, it is a consolidated program in two parts that utilize different aspects of the same sensor technology. The commonality in instrumentation and basic physics of guided wave ultrasonic inspection as well as the ultimate employment of common inspection service providers will provide a natural synergy to the overall program. Specifically, the program will demonstrate an EMAT Ultrasonic inspection of a pipeline covered with a thick tar coating as found on existing pipelines, and will develop procedures for measuring the level of residual stress and plastic deformation on pipelines that have been deformed by large movements of the earth supporting the pipeline.

Final Report

Final Report-DTPH56-06-T-0009

Final_Report-DTPH56-06-T-0009.pdf (213,135 bytes) [View] [Download/Save...]

Technology Demonstration Reports

Report of field success stories

ThroughCoatingFieldDemo-DTPH56-06-T-0009.pdf (168,200 bytes) [View] [Download/Save...]