Abstract
Protective coatings are used to protect the metal surfaces to hinder their direct interaction with service fluids. In this case study, a broad investigation was performed to determine the reason behind the failure of the FRE (fiber-reinforced epoxy) lining of a condensate storage tank located in the Arabian Gulf region. Visual inspections revealed various coating defects, including checking and crazing marks. Pull-off testing revealed that two out of six readings were not meeting the specifications for adhesion compliance. DFT (dry film thickness) checks revealed several locations, which were either undercoated or over coated beyond the specified limits. SEM (scanning electron microscope) analysis alongside the cross-sections revealed inter-layers delamination. In addition, the primer layer was visible from the surface, which implies the degradation of intermediate and topcoats. Finally, rust stains were visible at certain locations. FTIR (Fourier transform infrared) spectrum of the applied lining system indicated that it bears resemblance with phenoxy resin, which was in fact, incompatible with the condensate service. The failure mechanism leading to the failure of the applied lining is analyzed and discussed in this paper.
