Horizontal and vertical tanks await delivery at the An-Cor facility.
An-Cor tanks are certified to standards of the American Society of Mechanical Engineers and the Fiberglass Reinforced Plastics Institute.The filtration plant is part of the largest single construction project in the history of New York City. It is designed to ensure that water from the Croton System watershed meets all drinking water quality standards. When completed in 2012, the plant will provide roughly 10% of New York City’s 1.4 billion gallon average daily demand for water.
The project sponsor was the New York City Department of Environmental Protection, which will ultimately be responsible for running the plant.
To achieve a design capacity of 320 million gallons (1.2 million m3) per day, each link in the filtration process chain has been engineered for optimum reliability and performance. That is why An-Cor Industrial Plastics made 38 glass fibre reinforced polymer (FRP) composite tanks for the filtration plant to standards set by the American Society of Mechanical Engineers (ASME) and the Fiberglass Reinforced Plastics Institute (FRPI).
Tank manufacture
To achieve performance requirements, An-Cor, of North Tonawanda, New York, used Vipel® vinyl ester resins from AOC.
The inner corrosion barriers of each vessel were made with Vipel F010 bisphenol-A epoxy vinyl ester because of its excellent corrosion resistance and US Food and Drug Administration (FDA) compliance. The barrier liners were formed using hand lay-up of the resin with veils and fibreglass mats. In addition to the standard barrier, each tank designed to hold sodium hypochlorite added a 116 mil (2.95 mm) thick corrosion allowance for extending the equipment life.
Structural laminates were manufactured with Vipel K022 bisphenol-A epoxy vinyl ester. This resin meets project specifications for high strength, excellent chemical resistance and, with synergist addition, Class I fire-retardant properties according to ASTM E84.
The corrosion barriers of the cylinders were made using the hand lay-up method utilising fibreglass taped goods. Depending upon the diameter of the tank, the structural portion of the cylinders were built using mechanical applications of chop strand mat, woven roving, and/or winding glass.
The top and bottom heads of the 10 ft and 12 ft (3 m and 3.7 m) tanks were resin-infused using Vipel K022EBB resin. Balsa wood cores were encapsulated into the glass fibre reinforced laminate to achieve higher stiffness. The heads of the smaller tanks were made by hand lay-up of fibreglass and resin. All tanks were post-cured in a convection oven prior to shipment.
“The Vipel resins were selected for their ability to meet critical end-use performance specifications,” explains Rob Merrill, An-Cor Vice President-Operations. “The technical support that AOC provided with the resins was excellent. AOC Corrosion Specialist Bill Holtzclaw’s knowledge of FRP processing and quality standards was very helpful. Both Bill and AOC Product Leader Scott Lane were quick to respond when we needed to optimise processing.”
Certified
The tanks that An-Cor delivered to the Croton Project were backed by certification from two industry associations – the American Society of Mechanical Engineers (ASME) and the Fiberglass Reinforced Plastics Institute (FRPI). An-Cor is the first composite manufacturer to be certified by both organisations.
An-Cor is among a group of composite fabricators that meet certification requirements for ASME RTP-1 Reinforced Thermoset Plastic Corrosion Resistant Equipment. ASME certification ensures design rules, fabrication methods, testing procedures and quality control programmes are followed. Each tank was successfully hydro tested after installation at 5 psi (0.3 bar) to validate designs in accordance with the standard.
FRPI is a non-profit membership organisation that audits and tests laminates of corrosion-resistant equipment on a job-by-job basis.
“The versatility of FRP composites allows corrosion-resistant equipment to be custom-designed to meet specific project needs,” notes Gary Arthur, Executive Director and President of FRPI.
“FRPI certification tells specifiers and buyers that the FRP equipment materials for their project meet their specification. This provides confidence that the equipment will meet objectives for quality, consistency, reliability and performance."