Like the unstoppable Energizer Bunny®, Series 330 Tank Armor keeps going and going and going since first being applied on several petroleum storage tanks at a pipeline tank farm in Pasadena, Texas. “The tanks lined with the thick-film epoxy lining will have been in service for over 40 years on their next scheduled API (American Petroleum Institute) 653 inspection,” according to Tnemec coating consultant Eddie Borne.
Records indicate the tanks were lined in 1977 using Series 330 Tank Armor, a reinforced, 100 percent solids, epoxy lining for corrosion control, applied at 40 mils dry film thickness (DFT). The thick-film Tank Armor lining was spray-applied to the tank bottoms and 18-inches up the interior shell where the heaviest corrosion occurs due to water and bacteria which can cause microbiological induced corrosion (MIC). The tanks were originally used to store leaded gasoline and then later used to hold gasoline with MTBE. Today, the tanks are used to store gasolines and distillates with average ambient temperatures of less than 110 degrees F depending on the size of the tank and content turnover.
The tanks are periodically inspected under the API 653 standard requirements. According to tank farm personnel, the latest inspections consisted of scanning each tank using 100 percent Magnaflux technology to determine the thickness of the steel and to check for corrosion. Film thickness reading and visual inspections were also performed, and the lining in each tank was found to be in very good condition and put back into service with the next inspections scheduled 20 years from the time of the last inspection. Says Borne, “This will bring the age of the nine (9) liners to over 40 years of continuous service without the need for major repairs or replacement”.
“The cost of draining, cleaning and refilling large petroleum storage tanks can take up to one month at an estimated cost of hundreds of thousands of dollars”, Borne acknowledged. “When protective linings begin to fail, repair and replacement can cost as much as $500,000, so selecting protective interior linings with proven long-term performance can help reduce these costs by extending the service life of the petroleum storage tank”.
With some thin-film epoxy linings, recoating is often required after being inspected. Borne cited several examples including a large oil refinery in Louisiana where thin-film epoxy linings are being replaced every ten (10) years following inspections. “What a waste of time and money considering that tanks lined with thick-film material are lasting over 40 years,” Borne added.