51312-01673-IMPORTANCE OF LOCATING DISBONDED COATINGS WITH ELECTRO-MAGNETIC ACOUSTIC TRANSDUCER TECHNOLOGY

Available for download

Product Number: 51312-01673-SG

ISBN: 01673 2012 CP

Author: Richard Norsworthy

Publication Date: 2012

Member Price: $0.00

Non Member Price: $20.00

Price: $20.00

Qty:

ABSTRACT:One of the major issues in the pipeline industry is that of disbonded coatings that shield cathodic protection (CP) current. This allows potential external corrosion and stress corrosion cracking (SCC) to develop when electrolyte is present under the disbondment. A very large percent of the external corrosion and SCC found through internal line inspection tool (ILI) runs is under disbonded coatings that shield CP. This has been an ongoing problem with coated and cathodically protected pipelines since the beginning of using these two technologies. Until recently the industry has not had an effective method of locating disbonded coatings on in-service pipelines other than exposing the pipeline.With the continued development and improvements of the “Electro-Magnetic Acoustic Transducer” (EMAT) technology to locate SCC and disbonded coatings without having to expose the pipeline gives operators critical but economically feasible information about their pipeline systems. The “EMAT” technology is also capable of distinguishing between and identifying the various coating types and condition on a particular piping system. The EMAT coating information with identifying external corrosion locations through traditional ILI surveys will help the industry to start identifying and correcting potential problems with external corrosion and SCC before they become critical. Correlating the EMAT data with cathodic protection measurements data enables companies to distinguish between “CP shielded” disbonded coating areas and “CP open” coating holidays. This information tends to be relevant for SCC susceptibility models and Pipeline Integrity Management Systems. Another benefit may be the understanding of the various coating types and their compatibility with CP when disbondments occur. Eventually this will lead to better selection and use of coatings as well as the development of new coating products to effectively control external corrosion in conjunction with adequate CP even if disbondments occur.