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Storage Tank Coating Case Study

This particular case, they have couple tanks located in a very remote part of the state somewhere between Midland Lubbock, Texas and Roswell, New Mexico, in a very hard to reach areas which they needed to have two tanks that were used to hold produced water, they were basically overflow tanks that were reconditioned. They actually found that the whole bottom edge of the tank was so badly corroded that it should really have strip of steel welded in. Now there wasn’t time and crew available to do that so they went ahead and blasted all out and there are some pin holes, the largest being the size of a dime, along the bottom edge of that tank. And there are also holes on the actual bottom of the tank. The tank is an open top style. This is a common to earlier tanks. Modern tanks have closed tops so that, you know, things cannot evaporate from the top and rain water cannot get in. The unfortunate part of this job is it doesn’t rain very often in West Texas but when it does, it rains hard and in the middle of this job three inched rain fell at night and it flooded the whole area. Our crew was able to get ahead of that by simply, quickly coating the bottom of the tank and up to the sides somewhat even though the sand blasting wasn’t done on the top half of the tanks. They were able to get the coating in and cured far enough within half an hour so that when the water came in to the tank, it didn’t interfere with the coating job. The bottom of the tank is wet but it was already coated before the rain can do any damage. And the reasons the water is getting into the tank is the tanks are located on the secondary containment berm and those berms basically filled up with water. There were tarps put over the top of the tanks before the rain came in to keep the water from getting into the top. So because the Ecodur 201 coating cures so fast within half an hour to an hour being applied, the scaffolding of one tank was shifted over to the other tank and back to the first tank, so both of the tanks were able to be coated timely within a day. The holiday tests were done to look for defects – there are couple of touch ups were done in the tank and the job was finished on scheduled within the two days as allowed for that job and the crew was able to get home for the weekend. This would not had been possible with any traditional coatings that require more than four hours to cure because first of all you would not be able to move the scaffolding back and forth between tanks and can just partially coat the tanks as they go. And the amount of time required to do the inspection, followed by touch ups and again the inspection on the touch ups would have taken two day job and turn it into a week-long job. Now that would have been great, certainly is the normal way things are done in the Texas plains but with the weather being the way it was if that was start as a typical epoxy job its very likely that job would have need to be aborted simply because the water came in caused too much problem with the bottom of the tanks getting wet. They would not have the ability to get that job done so it would have required to reschedule that job which would require re-mobilizing a crew and of course having those tanks auto service for an additional week or two or longer, depending on how long to schedule a crew. So going back and looking at the results, the coating made the tanks look they are new on the inside. Certainly they are really were tanks that I would consider ones that are due for replacement not repair because of the severe corrosion particularly along the bottom edge and the bottom itself where there were actual holes through to the outside. I think the tanks will probably do just fine and they had them there for many years and I expected them to be there for a few more until such time they can get a replacement with newer tanks. So difficult job under difficult circumstances with very good results.
 
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