FRP Enters Cooling Tower Market

Bedford Reinforced Plastics, Inc.
Leads the Way
By: Andrea Hewitt Shope

A growing market for fiberglass reinforced plastics (FRP) structural products is the cooling tower industry. This industry offers tremendous growth in both sales potential and product development opportunities. A recent cooling tower constructed in the high desert region of Northern Nevada provided the ultimate forum for FRP to be used and proven as the alternative to wood and concrete for this application. Its size, its environmental purpose, and the extreme weather conditions it must withstand are three aspects that make the Barrick Goldstrike Mines water-cooling tower northwest of Carlin, Nevada a showcase for the benefits of FRP structural products.

Traditional materials used in the construction of field-erected water cooling towers are concrete and wood. The use of structural FRP is a recent development in the construction of larger field-erected towers and to date; the Barrick project represents the largest tower in the world to use structural FRP as its primary structural material.

Largest Cooling Tower Project in the World Uses FRP
When Barrick Goldstrike Mines, Inc. faced the need to cool water associated with their mining operation in Nevada (Figure 1), they contacted Kilborn - SNC - Lavalin Engineers of Toronto. Kilborn assessed the requirements for the tower and requested competitive pricing and ultimately contracted with Hamon Cooling Towers for the design, procurement and construction. Hamon engineers designed the tower to meet the water-cooling needs specified by Kilborn. Suppliers of materials provided proposals to Hamon and were awarded contracts on a competitive basis.

Standing 46' tall and spanning 1,080 feet in length and 54 feet wide, this is the largest water cooling tower to use fiberglass structural members. The tower includes two banks of 10 cells each. According to Dennis Haggerty, Director of Marketing and Sales from Hamon Cooling Towers, the size of this tower was primarily determined by the thermal duty application. Simply put, the greater the range of temperature that the water must be cooled (e.g. hot water = 100 degrees F and cooled water = 38 degrees F), the larger the tower. This tower is designed to process 65,000 gallons of water per minute. While this is not a huge volume for a tower to handle the thermal duty is what makes this project truly unique.

While most water cooling towers associated with power plants or industrial facilities cool water that is used in a process for re-use, the purpose of the Barrick tower is strictly environmental. The only reason a tower was needed for this gold mine was to comply with environmental regulations governing water temperature before it is discharged into a river.

The unique application for this tower is simple to conceive, yet difficult to achieve. In the gold mine's operation the water table in the immediate area must be drawn down to allow development of the underground mine. There is naturally occurring water that regularly runs into the underground mines. This water must be pumped out of the mines so that the mining and development can continue. Because it comes out at a temperature of 130 to 140 degrees, the water must be cooled before it can be released into the Humboldt River. Making this even more of a challenge, the temperature of the Humboldt varies according to season ranging from 80 degrees in summer down to 32 degrees in winter. The design of the water-cooling tower had to allow for this seasonal variance between the water temperature of the river. Environmental regulations state that water released must closely approximate the temperature of the river.

Larry Morasse, construction manager of this project for Barrick, says the true challenge to the tower will come in the winter months when the temperature of the river can sink down to 32 degrees F. He says that this project will be the ultimate test for the FRP tower since the weather conditions are so extreme. In the winter the air temperatures can dip down to -20 degrees F and in summer they can be exceed 100 degrees F.

Bedford Reinforced Plastics Offers Unique Benefits
Bedford Reinforced Plastics (BRP) (Figure2) was chosen to supply the FRP structural members on this project for several reasons according to Dennis Haggerty of Hamon. In a bidding situation, price is always a factor but Haggerty stressed that the company's experience in supplying material for water cooling tower projects combined with their capacity to deliver the product within a tight schedule were both significant factors in the company's selection as the supplier. Other issues that became important to this project was BRP's ability to fabricate the structural members and their ability handle a rigorous delivery schedule including an emergency shipment.

A CNC Contour Router (figures 3 & 4) provided BRP with the ability to further automate their fabrication capabilities in the pursuit of the water cooling tower business and made production of this product possible within tight deadlines. Because the structural fiberglass used in the water cooling tower applications requires thousands of holes for connections, the CNC makes BRP more competitive in this market since the machine increases production speed as well as ensures consistency and accuracy. These benefits allow a substantially reduced lead-time in both the fabrication and the installation of the product. Consistent and accurate connector holes allow for ease of installation on-site. Another benefit of using FRP over wood or concrete is the lightweight properties of FRP that make installation simpler and smoother.

BRP began supplying materials for the project in March 1997 and completed deliveries July 30, 1997. The company shipped a total of 29 flat bed trucks loaded with a variety of structural members. Weighing over 612,734 pounds and measuring 395,094 feet, the shipments included square tubes, angles, channels, and deck board.

Materials used in BRP's production of the cooling tower's structural shapes included Owens Corning continuous strand mat and uni-directional roving fiber, Ashland Chemical fire retardant isophthalic polyester resin, and Nexus polyester surfacing veil for protection from UV exposure.

Bedford Reinforced Plastics Responds to a Serious Challenge
During the construction phase of this project there was an incident that occurred on-site that required speedy and efficient response by BRP. On July 2, 1997 a very high velocity localized windstorm gust damaged fourteen bent line sections that were being erected at the time. Staff from BRP traveled to the site to inspect the damaged material and assess the condition of the remaining FRP members. The company produced the entire shipment of replacement materials by July 9, 1997 and had it on site for erection on July 12. This emergency shipment consisted of two trucks of materials totaling 33,000 lbs. and 21,000 feet of structural FRP.

The Construction Superintendent for Kilborn, Nick Mills, said he was pleased with the response time and the cooperation of BRP when this incident occurred. "They responded quickly and considerately," said Mills. According to Mills, this was the first large fiberglass tower he worked on and he commented that the FRP structures went together well. He commented that BRP's quality control was good and there were no problems with the materials.

Practically Entire Tower is Constructed of Plastics
According to Dennis Haggerty; practically this entire tower was constructed of plastic. Products ranged from PVC pipe, PVC nozzles, polypropylene heat exchange surface (fill), FRP fan stacks, FRP fan blades, FRP siding and other products. Haggerty said the only parts of the tower that are not plastic are the hardware, motor and gear reducers.

Midwest Towers, Inc. of Chickasha, Oklahoma supplied the twenty fan stacks for the project. Constructed of FRP, fan stacks are designed to shroud or enclose the fans at the top of a tower. The fans direct the airflow out of the tower and release the heated air into the atmosphere. The fan stacks for this project were 10 meters in diameter and 10 feet high. According to Terry Ogburn, sales manager for Midwest Towers, Inc., fiberglass fan stacks have excellent value because they offer simple field installation, they resist vibration and flexing, and they are available in many sizes and profiles.

American Tower Plastics Inc., a Sanford, North Carolina company, and a sister company of Hamon Cooling Towers, supplied drift eliminators and fill components for this project. The drift eliminators, constructed of thermo plastics, are designed to eliminate the drift or mist that is often seen escaping from the top of a water-cooling tower. The fill is constructed of polypropylene. The fill is the medium that water trickles through to reduce the size of the water droplets as part of the cooling process.

Other FRP products in this tower included the fan blades and the corrugated siding.

FRP is the Product of the Future for Cooling Towers
FRP can be touted as the most shippable and most flexible of all possible materials used in the construction of water cooling towers. In a recent issue of the Cooling Tower Institute Journal, Christopher W. Carlson, P.E. with the Baltimore Aircoil Company listed six typical reasons why fiberglass is chosen over concrete for structural components in a water-cooling tower. Among these Carlson concluded that fiberglass structures require less maintenance and are more corrosion resistant than concrete structures and that fiberglass structures are available at a higher level of quality since the parts are fabricated in a controlled factory environment as opposed to being subject to varying field conditions.

FRP is much easier to ship to and erect in remote locations and is less expensive than concrete. While not a major concern, FRP is often preferable to wood in instances where environmental issues are a factor since it has no preservatives that could leach into the water that is being cooled.

According to materials published by Hamon Cooling Towers, some of the properties of FRP that make it a viable solution for the water cooling tower industry are: high strength, light weight, corrosion resistance, quality fabrication, fire resistance, stability, non conductive, not preserved with chemicals, and it is very stable.

Opportunities Abound for FRP in the Cooling Tower Industry
Although the Barrick project was designed for a unique environmental application; there are tremendous opportunities for FRP products in the cooling tower industry as a whole.

According to Haggerty, this industry is growing internationally as many lesser-developed countries continue to participate in development projects to bring electrical power to their industries and inhabitants. When a power plant is built, a water-cooling tower is almost always part of the construction. When certain banks fund such projects, many of the materials must be purchased from suppliers in the United States. This increases the opportunities for suppliers in the US to supply materials for these projects.

Although the U.S. market for cooling towers is primarily related to the construction of power plants, which is down currently, Haggerty says the cycle may be picking up again in the near future. There are also thousands of older wooden cooling towers that will need to be re-built over the next decade. A trend may be starting to replace the wood tower with FRP because of its durability in many conditions. There are also many other applications for FRP cooling towers including industrial and commercial facilities.