The order included four field-erected vertically wound composite tanks with diameters of 23-30 ft. The tanks were fabricated off-site and installed during the winter months within “very short lead times.” All the FRP tanks were produced with Ashland Derakane 411 and 470 VE [vinyl ester] resin systems.
The tight schedule meant ECC had to manufacture its own custom vertical winder, which turned out to be 20% cheaper than a commercial one.
In addition to the four vertically-wound composite tanks ranging in size from 23 ft diameter by 30 ft, to 30 ft diameter by 43 ft, ECC produced three other large tanks in a one-piece fabrication ranging in size from 16 ft diameter by 21 ft, to 20 ft diameter by 34 ft.
The seven large FRP tanks were produced with a corrosion barrier. Eleven smaller tanks ranging from 4 ft diameter by 5 ft to two tanks that were 14 ft diameter by 24 ft were also produced.