PHMSA Research and Development
Time: 11/23/2009 09:54 PM

Feasibility of an Ultrasonic Based Instrument for Assessing In-Situ Pipeline Coatings

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Main Objective

A solid basis for the development of an instrument to provide in-situ measurement of pipeline coatings properties. The measured properties being selected as they pertain to coating fitness for service and for use as guidelines for assisting ultrasonic inspection.

Technical Objectives:
The overall end objective is the realization of a device that can be used to characterize and archive in-situ pipe coating properties. There are other objectives that must be attained before achieving this end objective. Through modeling and experimentation we must develop a programmable "algorithm" for implementation as a hardwired/software device for coating characterization.
1) Creation of a library of measured ultrasonic coating properties. Longitudinal and torsional bulk waves and longitudinal and torsional guided waves will be used to obtain the measurements. Specific measurements will be based on their relevance to pipeline inspection and coating assessments.
2) Refinement of their evolving 3-layer coating model to accommodate dispersion curve and wave structure generation for very attenuative coatings and a broader range of coating conditions.
3) Correlation of ultrasonic measurements with mechanical properties and inspection parameters. Provide the mechanical properties to pipe engineers for correlation with fit for service conditions and for feedback to FBS, Inc. The 3-layer model will be used as part of the process to achieve this objective.
4) Creation of a data format for use by inspection personnel and piping engineers that enables simple extraction of inspection parameters and coating assessment features.
5) Designation of the computational capability that a coating assessment instrument must have and specification of the ultrasonic sensors needed for data acquisition.
6) (pending Phase II funding) Design and fabrication of a prototypical coating evaluation instrument.

Public Abstract

FBS, Inc. proposes to establish the feasibility of an ultrasonically (UT) based device for in-situ evaluation of pipeline coatings and for the archiving of coating properties. Based on their experience gained through DOT and EPRI sponsored work on long range ultrasonic, buried pipes, and tar coated pipes they recognize the need for coating characterization not only as an important factor for inspection design but for chronicling the effects of service, age, and environment. They FBS, Inc. have approached characterization through modeling and through empirical methods and have found significant differences between published coating properties and in-situ measured properties. Coating properties determine ultrasonic wave characteristics (e.g., velocity, attenuation) and conversely, ultrasonic propagation characteristics can be used to ascertain material properties. The collection of in-situ measured values establishes a "fingerprint" for a coating at the time of the measurement. Thus archived measured values can believe the "intelligence" necessary to perform the measurements, archive them, and to guide inspection design can be bundled into a hand held device interfaced with a minimal ultrasonic package and/or with a commercially available UO inspection system.

Final Report
VOLPE Final Report
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