03 September 2006
03 September 2006
Thanks to 23-year-old storage tanks made with Vipel resin technology available today through AOC, guests at the remote LeConte Lodge in the Great Smoky Mountains National Park enjoy running water.
Reached only by strenuous hike, the mountaintop Lodge is on the Park’s 6,593-foot (2,010-metre) high Mount LeConte. The Lodge water system uses three fibre-reinforced polymer (FRP) composite tanks. The horizontal, aboveground tanks were airlifted by helicopter to the mountaintop in 1983 when the Lodge upgraded its water system and increased capacity 50% by replacing a redwood storage tank.
“The composite tanks have been very dependable ever since they were installed,” said Tim Line, General Manager/Owner of the Lodge. “On occasion we’ve wiped off a film that naturally builds on the exterior over time, but that’s about the extent of any tank maintenance we’ve had to do.”
One of the composite units is a 6-foot (1.8-metre) diameter, 3,000-gallon (11,360-litre) holding tank. The other two are 8-foot (2.4-metre) diameter, 7,600-gallon (28,770-litre) supply tanks installed side-by-side. The smaller holding tank is near the mountain’s ever-reliable Basin Spring. Spring water naturally accumulates in three adjacent collector units that feed the holding tank. Gravity-powered water from the holding tank activates the hydraulic ram of a pump that transfers water uphill through piping to the supply tanks. “For every ten gallons of water used to move the ram, one gallon is pumped up to the supply tanks,” Line pointed out. “The other nine gallons end up as Roaring Fork River miles downstream.” When it is sunny enough, the ram can be activated using solar power. In rare cases when holding tank water levels run low and sunlight is insufficient, a gasoline-powered pump is available for back-up.
The tanks were made by the former Tank Division of Owens Corning who sold the division to Containment Solutions, Inc., in 1995. Tank end caps and cylindrical shells were manufactured using a resin and chopped fibreglass spray-up process. The resin was an isopolyester engineered for potable water use by the Owens Corning Resins & Coatings Division, which became a co-founding partner of AOC. Each tank has two exterior ribs that allow the tank to be supported by setting the ribs in metal cradles covered with a layer of resilient material. The shell wall thickness was increased in the locations where the ribs were applied. The ribs were fabricated by wrapping the tank with a hollow rib form over which fibreglass woven roving, chopped fibreglass and resin were applied. The crown or top of the rib form incorporated continuous glass fibers which provide maximum stiffening by creating high modulus at the maximum distance from the shell wall.
To resist ultraviolet degradation, a UV inhibitor was incorporated into the resin for the exterior layers of the tank and ribs. For additional UV protection, the tanks were coated with a gel coat consisting of highly-pigmented resin.
“The proven performance of Vipel resin at LeConte Lodge is a testament to AOC’s corrosion resin technology,” stated Emilio Oramas, AOC Business Manager for the corrosion market. “Today’s Vipel resin technology can offer the same combination of excellent corrosion resistance, structural properties and potable water code recognition.”
The image shows a helicopter airlifting the tanks to the mountaintop 23 years ago.