Over-design also occurs when customers aren’t knowledgeable about composites. Plas-Tanks recently fabricated three tanks, 13 feet in diameter and 31 feet long, for a chemical manufacturing plant in the Middle East to store hydrochloric acid. In addition to the tanks, the company produced GFRP saddles to support the horizontal tanks. “Our saddles are typically hollow inside, but the end user was hesitant to use hollow saddles,” says Puthoff. “They didn’t think it would be supportive enough, so we are filling the saddles with resin to provide additional strength properties. It isn’t required for support, but it will give the end user ease of mind.”
In Clarkson’s experience, when tanks fail it’s often not the fault of the material or construction. “A lot of problems that people have with FRP are related to how the tank was installed in the facility and what happened to it – things like process upsets, where there was a temperature excursion or a pressure spike,” he says.
Working hand-in-hand with designers and engineers during the design process can help combat process upsets and other on-site failures, in addition to curtailing over-design. “It’s worthwhile for manufacturers to really quiz end users on their process controls,” says Clarkson. For example, if fabricators ask customers to fully explain where and how the tanks will be used, then they may be able to offer design advice to head off potential problems with temperature deviations, pressure spikes and other issues.
“A number of failures or near failures we’ve observed have occurred because somebody took a short cut at the design stage,” says Clarkson. “It’s in the best interest of the buyer to have somebody go through the details and look at how the equipment is put together, installed and used.”
A well-designed, well-made FRP tank can be virtually maintenance-free and last for decades. “Composite tanks are lasting a long time – and can last even longer,” says Clarkson. “But we have a significant need globally to give good advice on fitness for service and the ability of a storage tank to stay in service.”
Collaboration Is Key to Market Growth
The best way to advance the use of composites in the tank market is for industry experts to work together with their peers, as well as engineers, designers, consultants and others in the market. Both Schoessel and Puthoff are part of a group that meets twice a year to discuss the American Society of Mechanical Engineering’s RTP-1 standard for reinforced thermoset plastic vessels. The group has open discussions about end user needs where members share ideas. It also has a sub-committee dedicated to marketing, which is planning a conference to educate engineers about FRP tanks.