Cases from the F-Files, 2011
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“The Case of the Sliding Lining” – This case from the F-Files concerns the application of a high-performance liner in a steel demineralized water storage tank, or a demin tank, at a charcoal manufacturing plant. Demineralized (purified) water can be particularly aggressive in service when even minute traces of soluble salt contamination are on a substrate beneath the lining. Therefore, it is not uncommon to see soluble salt remediation and high degrees of surface cleanliness (e.g., SSPC-SP 5, White Metal Blast Cleaning)required before lining installation. The generic type of liner is normally chosen based on superior chemical and water immersion resistance.
Rich Burgess, Senior Coatings Consultant and Series Technical Editor
“The Shop-Coated Pipeline That Cracked” – Gas transmission pipelines are often coated in a shop using fusion bonded epoxy (FBE) coating systems. These coatings are chosen for their resistance to chemicals in soil and excellent impact resistance, which means less damage during the transportation and installation of the pipe sections and less mechanical damage during backfilling. Shop operations for abrasive blast cleaning and coating application are automated, and the resulting applied films are generally uniform. One drawback is that the weld areas and joints that connect pipe sections must be prepared and coated in the field are generally not as uniform and consistent from “joint to joint” as are the “stick to stick” shop-applied coatings. A second drawback with the same FBE coating materials applied in the shop is that they are more difficult to apply in the field due to widely variable environmental conditions.
Valerie Sherbondy, Senior Chemist
“The Case of the Gasoline Storage Tank Linings” – This case involved the investigation of alleged failures related to a large class-action lawsuit between a gasoline refinery and a number of gasoline service station owners. The service station owners claimed that the refinery had not suitably removed contaminants from the gasoline they sold after crude oil refining.
Kenneth B. Tator, P.E.
“The Case of…Not All Coating Systems are Created Equal” – An industrial equipment manufacturer in the mid-west U.S. needed to find a new coating system when its current coating supplier went out of business. The company had previously used a two-coat alkyd coating system with good results. A small coating manufacturer in the region was contracted to manufacture and supply a coating system suitable for use on the equipment. The service environment for the various manufactured steel equipment (once coated) was interior and exterior exposure.
Jayson L. Helsel, Senior Coatings Consultant
“The Case of the Coal Tar Epoxy That Fizzled” – One of my clearest memories from my seventh grade general science class is one of our “lab day classes,” when we saw what happened when a (weak) acid solution was dropped onto rocks. The drops began to bubble and fizz when the acid landed on some of the rocks, but it did nothing exciting when it landed on other rocks. The lesson? Rocks made of limestone fizz when treated with acid. Through trial and error around the home, similar experiments on all sorts of surfaces segregated the fizzers from the non-fizzers. Concrete and cement were in the fizzer group. Fun? Certainly. Useful? Perhaps, as we shall see from this month’s case.
Ray Tombaugh, Senior Coatings Consultant
A Case of Premature Coating Failure on the Interior Surfaces of Bridge Box Girders” – What are exposure conditions like inside the large box (tub) girders of a bridge? Should they be considered interior surfaces or exterior surfaces? Whatever you consider them, as this case shows, girder interiors should not be ignored surfaces.
James D. Machen, Senior Coatings Consultant
“The Case of…The Fix is Worse than the Problem, Sporadic Coating Delamination from Brick on a Historic Building” (PDF 495Kb) The restoration of historic landmark buildings can be very challenging. The structures often contain multiple coats of paint (some containing toxic metals like lead), and the substrate may be deteriorated or may contain moisture from centuries of exposure to the environment. Removal of the existing paint layers without damaging the substrate often requires specialized equipment and expertise. Oftentimes the building owners requires new paint systems to match the color of the original paint, which can be very difficult to achieve and is often based on a match to the color of the paint as it is today. The bottom line is that removal and replacement of the existing paint systems on historic buildings can be an expensive undertaking, and it is important that the new coating system protect the structure for as long as possible.
Chrissy M. Stewart, Chemist
“The Case of the Balking Bulkhead” (PDF 278Kb) Coating specifiers, contractors, or manufacturers are often blamed when installed coatings fail to meet service life expectations. March’s Case from the F-Files describes the rapid deterioration and failure of a sheet pile coating system because of errors from both the applicator and the facility owner.
E. Bud Senkowski, PE, Senior Coatings Consultant
“The Case of the Coating Failures Waiting at the Train Station” (PDF 1.68MB) A single aesthetic coating problem can warrant a field investigation to determine the cause and corrective action. Often, however, an appearance issue leads to the discovery of other coating problems, sometimes related, often unrelated. This month’s F-Files is a case in point. Porcelain enamel-coated decorative panels installed in commuter train stations were exhibiting rust stain and corrosion. The investigation of the appearance of the panels expanded to include several other coating problems.
Cynthia L. O’Malley, Manager, Laboratory Services
Rich Burgess, Senior Consultant and Series Editor
“The Case of the Ship Paint That Wasn’t All It Was Cracked Up to Be” (PDF 924Kb) The application of silicone alkyd finish coats to exterior surfaces on marine vessels provides an economical alternative to polyurethane, polysiloxane, or fluorourethane finish coats. Silicone alkyds provide good barrier protection, retain their color and gloss (provided they contain 30% or greater silicone in the formulation), and are easily touched up during maintenance operations. In this Case from the F-Files, however, a silicone alkyd finish coat failed prematurely on the exterior of a U.S. Coast Guard vessel.
Rick A. Huntley, Manager, Consulting Services
Rich Burgess, Senior Consultant and Series Editor
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