Fusion bonded epoxy (FBE) coatings protect the underlying metal from corrosion by creating a barrier against corrosive chemicals and moisture. However, pipeline coatings fail due to cathodic corrosion, disbonding, improper application, or improper curing being investigated as root causes. Rarely is microbial activity considered, even though microorganisms can degrade bisphenol, a component of FBE coatings. Research in the waste industry has demonstrated that microorganisms can corrode concrete sewers and other protective surfaces including concrete linings, cement based coatings, and epoxy-mortar coatings. The lack of research on the microbial impact of pipeline coating failures leaves a significant knowledge gap. We analyzed two FBE coating samples from buried steel transmission pipelines with unusually rapid external pitting. One pipeline was so newly constructed that cathodic protection (CP) had not yet been installed. Nevertheless, it developed a deep pit (80%) in less than a year. The other pipeline had CP, but corroded at 1 mm/year. Quantitative polymerase chain reactions (qPCR) analysis revealed moderate to high levels of Microbiologically Influenced Corrosions (MIC) organisms. This led us to investigate the potential ability of microorganisms to degrade/disbond pipeline coatings through genetic analysis, evaluating the possibility of corrosion on coated coupons in a laboratory simulated environment, and qPCR analysis. The results will be used to understand the potential implications of MIC on FBE coatings.
Key words: downloadable, FBE coatings, microbiologically influenced corrosion, MIC, pipe failure, coating failure