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Never Again Cracking within the installed lining system evident with rust stains for the exposure of the carbon steel substrate. inspection of various locations continued as the investigation expanded. Te areas that had been hydrostat tested provided obvious visual indications of the cracking; the staining from the rust showed on those areas. But to evaluate areas not previously hydrostat tested, a dye-penetrate was randomly used mostly on pipe sections that remained above ground along the pipeline rightof-way. Te result: testing in these sections revealed that cracking was evident. It also revealed that checking of the lining system (cracks that had not yet penetrated to the substrate) was evident as well. See the checking shown after dye-penetrate was used in the photo to the right. Samples of the installed linings in areas exhibiting cracking and checking were collected for further laboratory analysis. It should also be noted that the investigation showed areas of the installed lining system that did not exhibit any failure. Samples of those areas were collected as well for comparative analysis. Once the samples were brought into the lab, microscopic analysis of the lining/substrate cross-section was performed to verify that the evident cracking was in fact down to the substrate. See photo on page 92 to see what was found in the lab. 94 Back at the Lab One of the correlations that became evident during the feld portion of the investigation was that the lining systems that had remained for the longest durations — up to 18 months — on the pipeline right-of-way prior to burial also exhibited a greater frequency of the observed failure phenomena. Te longer the areas of pipe sat aboveground, the more cracking and checking occurred. As it turns out, these areas had been exposed to extreme temperature variations between hot and cold as well. Te observed failure modes were apparent in both the mainline lining as well as in the feld-joint linings of the joined sections still awaiting placement and burial. Tis indicated that the phenomena were not specifc to either the mainline application or the feldjoint application. Laboratory analysis provided insight as to the mechanisms that caused the observed failures (i.e., the checking and cracking). Samples that had been collected from the pipeline that showed where the lining system had cracked and checked portrayed Plasticizers had evacuated from the lining film to a greater degree in these areas than in the areas that did not exhibit cracking and checking. JANUARY 2014 COATINGSPROMAG.COM Checking of installed lining system made evident through the use of dye-penetrate.