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78 SEPTEMBER 2015 COATINGSPROMAG.COM sections needed to be repaired and rehabilitated before we could apply the coating system," said Harnage. Te concern over the areas of cracked concrete was two-fold: Not only could the water contained in the reservoir tank leak out, but groundwater could seep in, causing possi- ble contamination. In some sections of the tank, there were large cracks that required the injection of hydrophilic epoxy. According to Harnage, the AV202 material, manufactured by Avanti International, is liquid when injected into substrate but cures to a solid when it comes in contact with water. Tis ensures that water does not continue to work its way through the concrete. Ten, a BASF repair mortar, or what Harnage referred to as a water plug, was trowel-applied over the hydro- philic epoxy. Te repair mortar is chemically formulated to stop leaks and keep the substrate watertight. During this process, the crew wanted to ensure that the tank stayed completely dry, so they brought Frost Fighter forced-air heaters inside the tank. "Te heaters not only helped dry out the tank but also helped to warm up the ambient air a bit," said Harnage. Low Temps? No Problem With morning temperatures averaging in the teens and only warming up to around 29–35° F (-1.7–1.7° C) during the day, Mother Nature was defnitely not going to help speed up the job. To combat the sub-freezing temperatures, the crew warmed the coating to 150° F (65.6° C) prior to spraying it. Tis was necessary in order to make sure the coating material was not too viscous to spray. "We placed small heaters in the trailer that we ran for anywhere from 30 to 45 minutes to up to three hours before spraying to heat the barrels and ensure that the material was thin and warm enough to spray. Unlike most epoxies and urethanes, however, we could still apply the Ecodur 201 even in such low temperatures. It was a sound application process, and the coating adheres just as well as it does when the ambient temperature is in the 50s [10° C] or higher," explained Harnage. Te Ecodur 201 was spray-applied using specially modifed Graco equipment. "Our Graco pump, Graco/Glascraft P210 spray gun, and hoses have all been modifed to efciently and efec- tively spray the Ecodur 201 coating," explained Harnage. Te crew installed the coating system at a thickness of approximately 100 The crew coated higher areas on scaf folding. "The scaf folding was a s s e m b le d i n s i d e th e t a n k ," H a r n a ge s a i d . " It co m e s a p a r t a n d travels easily but is a secure and safe scaf fold system that includes hand rails." T h e c r e w s p r ay - a p p l i e d t h e E c o d u r 201, w h i c h h a s n o v o l at i le o r g a n i c c o m p o u n d s ( VO C s), u s i n g a G r a c o p u m p a n d G r a c o / Gla s craf t gun. It wa s sprayed at an approximate thickne s s of 100 mils (2,540.0 microns). The coating is fa s t curing , w hich meant that the crew applied one layer to a s ec tion of the re s er voir and then imm ediately returned back to apply another layer to achieve the desired thickness. In total, it took the crew approximately one day to dr y out the tank, four days to repair the leaks, four days to apply the coating system, and one day for inspections and touchups. Reservoir Challenge