However, HDPE probably won’t meet the structural requirements for tanks with about a 15,000-gallon capacity or above, says Coe. He recently got a call from a potential customer in need of six 50,000-gallon underground tanks. “That eliminates HDPE and makes FRP competitive with concrete,” he says. “It’s right in our wheelhouse to deliver that much storage to a site that’s watertight and will last a lifetime.”
Another option in the tank industry is dual laminate FRP composites, which combine a thermoplastic inner liner with a GFRP exterior. Dual laminates grew in popularity as customers required tanks that could store high-temperature gases or liquids that were more caustic or under higher pressures.
“Thermoplastic liners typically have the ability to contain all that, but don’t have the structure to support it like a fiberglass piece of equipment can,” says Tim Schoessel, president and owner of Tri-Clor Inc., a fabricator in Hastings, Mich. “In dual laminates, the two materials are married and work well together.” In corrosive environments, such as the chemical processing industry, they compete well against metals like high nickel alloys and titanium.
Advancements in Material Technology
Increasing end user demands drive innovation in composites. “Our customers in the chemical world are trying to stretch the limits of their equipment,” says Schoessel. “If they push the boundaries, then we follow closely behind and develop the equipment they require.”
Suppliers aid the cause with new resin and fiber technology. “Materials have advanced,” says Joe Puthoff, president of Plas-Tanks Industries Inc., an FRP vessel manufacturer in Hamilton, Ohio. “We’re still using resin and glass to build the tanks, but new technologies allow us to offer better corrosion resistance [to customers] and improve efficiencies in our facility.”
The latter – improved efficiencies – is critical to fabricators seeking a competitive edge. INEOS Composites in Dublin, Ohio, is one of several resin suppliers introducing new, more efficient products to the market. In 2018, INEOS rolled out its Derakane™ Signia™ line of epoxy vinyl ester resins, which are formulated to offer faster laminate consolidation, lower foaming and reduced sanding for application of secondary laminations, according to Kevin Lambrych, manager of the INEOS Corrosion Science Center.
The Derakane Signia resins also provide improved cure kinetics. “That allows fabricators to process thicker parts,” says Lambrych. “The parts cure without excessive heat, so they don’t warp, twist or burn.” In addition, the new resins contain a novel vapor suppressant technology that forms an air activated film, thereby reducing styrene emissions during curing. “That’s beneficial to us in the plant and from an environmental standpoint,” says Puthoff.