Improving pipe performance

December 2010 » Products » ENGINEERED SOLUTIONS
Pipe manufacturers work to decrease pipe cost and joint leakage.
Stephanie Hildebrandt

The American Society of Civil Engineers’ 2009 Report Card for America’s Infrastructure gave the nation a D- in wastewater. The report also noted that in order to meet increasing demand, the U.S. Environmental Protection Agency (EPA) estimated the United States must invest $390 billion during the next 20 years to update or replace existing wastewater systems and build new ones. America’s pipelines may be “out of sight,” but with results like these, it’s obvious the nation can’t afford to put them “out of mind.”

Trends
Owners and engineers are looking for long-lasting, high-performance pipe, but in a down economy, they’re also being cost-conscious.

“In tough economic times, the design engineer must strive to develop more cost-effective design solutions that meet the design-life requirements,” said Andrew Jenkins, national plastic products manager, CONTECH Construction Products Inc. “The key to their success will be their ability to communicate the value of innovative solutions with their clients.”

Other cash-strapped agencies “are looking at non-traditional materials to promote competition and drive project costs down,” said Greg Baryluk, Advanced Drainage Systems Inc.’s (ADS) water quality market manager. Additional trends in the pipe industry include expanded opportunities for “green” infrastructure, such as recycled content pipe, and testing and certification requirements for all pipe types, he added.

“New requirements for raw material testing/certification, manufacturing compliance, installation inspection, and post-installation testing are all added requirements within sanitary and storm industries today,” said David Martin, ADS. “The requirement for water-tight joint performance for both storm and sanitary systems continues to be a design factor for many owners and engineers. New pipe types and structures are evolving to fill this need. This year alone, two new ASTM standards were developed in the United States for polypropylene pipe.

“These expanded testing requirements are directly related to an increasing trend of performance awareness. Many traditional materials that were once considered to have no performance issues are now being evaluated for material, installation, and performance compliance,” he added. Although these strict requirements may enhance the quality of installations, they also increase costs, leading many to turn to more cost-effective pipe materials, Martin said.

One of the most important performance requirements for specifiers is joint leakage. By reducing or eliminating joint leakage, owners and engineers are saving water and, according to HOBAS Pipe USA Inc., decreasing total costs over time. One way of reducing or eliminating joint leakage is to use life cycle analysis. “These models generally include the cost to install, operate, and maintain the line,” said Kimberly Paggioli, P.E., vice president of marketing and quality control for HOBAS. “One example of such a model is a project funded by participating industry members and the EPA Office of Wastewater through a grant to the Fiberglass Tank & Pipe Institute. The model, which is centered mainly on joint leakage, predicts life cycle costs for different infiltration rates of large-diameter sewer main collection system joints.”

Jerome Silagyi, P.E., manager of technical services, Lane Enterprises Inc., also supports the idea that one of the largest growing factors influencing the use of drainage pipe is related to joint performance. “Historically, the pipe application or the natural environment dictated the level of joint performance needed to properly sustain a site,” he said. “This pragmatic approach was responsible for developing and defining terms such as soil-tight or silt-tight. However, with increasing applications for underground detention and water reclamation along with their green incentives, coupled with manufacturers differentiating themselves in the marketplace with newer and better products, it seems today’s design engineer is under constant pressure to specify tighter leakage requirements.”

So how can engineers address this issue when specifying pipe for stormwater or wastewater projects? According to Silagyi, they can do so by understanding the difference between laboratory-certified joints and actual field performance. “The level of leak resistance measured in a controlled environment does not translate to in-ground performance and is not intended to do so,” he said. “The steeped pressure ratings measured in the laboratory are designed to mitigate in situ leakage to acceptable levels, and there is no clear-cut correlation between manufacturer certifications and actual performance. Moreover, the oft-used term ‘water-tight’ is misleading specifiers to think in an absolute sense, resulting in unrealistic and unattainable installation acceptance and testing requirements. Engineers must address the necessity of stringent joint performance before opting for the ‘better’ product to eliminate any undue project costs and prolonged construction delays.”

Because pipelines serve as the foundation for many transportation and commercial projects, they must be able to withstand the test of time. This means strength, durability, corrosion resistance, fire/melt resistance, and sensitivity to installation are all important factors influencing the selection of pipe materials for these critical projects, said Rick Traylor, P.E., vice president of technical services, Rinker Materials Concrete Pipe Division.

To meet these expectations, engineers should consider a sound design method based on nationally recognized specifications, such as from the American Association of State Highway and Transportation Officials, and accomplishing a successfully installed pipe system, Traylor said. “Flexible pipe materials must have carefully constructed soil envelopes around the pipe to ensure proper performance,” he said. “Rigid pipe materials are not as dependent upon the proper construction of the soil envelope since the inherent strength of the product carries the majority of the load. This makes the product less sensitive to proper installation.”

(above) ADS SaniTite HP pipe meets new ASTM Standards F2736 and F2764 due to its material, construction, and joint performance. (below) HOBAS Pipe USA’s pipe products feature corrosion resistance, hydraulics efficiency, leak-free joints, and high structural strength, all contributing to a long, maintenance-free life and a low life-cycle cost.

Products
CONTECH offers DuroMaxx pipe, a high-performance, steel-reinforced polyethylene pipe that ranges from 24 inches to 96 inches in diameter. The polyethylene material is pressure-rated and reinforced with high-strength steel to provide the structural capacity and to enable the use of high-performance materials, Jenkins said.

To support the trend toward green infrastructure, ADS promotes its ASTM F-2648 pipe — especially in LEED applications — to address recycled content requirements.

To meet other industry needs, ADS utilizes TripleWall manufacturing technology and polypropylene raw materials to increase the level of performance for its sanitary and storm sewer applications, Martin said. The company’s SaniTite HP product line focuses on joint performance — which remains an important design factor — and pipe stiffness to add value, he added.

To keep its products maintenance-free with a low life-cycle cost, HOBAS offers pipe with leak-free joints, high structural strength, corrosion resistance, and hydraulics efficiency, Paggioli said. In addition, the company responds to the needs of engineers, owners, and installers by providing a full engineering department to assist designers with specification and installation advice, as well as a field service department.

(above) Rinker Materials Concrete Pipe Division’s polyvinyl chloride or high-density polyethylene-lined concrete pipe can provide a robust structural solution with protection against chemical attack. (below) Three miles of DuroMaxx steel-reinforced polyethylene (SRPE) pipe provided an effective and economical solution for low head water transmission on the Barker Ranch irrigation ditch enclosure project in West Richland, Wash.

Rinker Materials Concrete Pipe Division aims to educate specifiers about the characteristics of concrete pipe, including its performance and green attributes. Because of concrete’s longevity, concrete pipe systems do not require rehabilitation or reconstruction often, enabling the consumption of fewer natural resources and energy while decreasing traffic congestion and pollution, Traylor said. Concrete pipe utilizes recycled materials — it is recyclable itself — and primary ingredients that are naturally occurring, he added.

Conclusion
In the end, “Failing drainage infrastructure caused by relatively short-life materials has design engineers more carefully contemplating the proper design and use of piping materials for current projects,” Traylor said. It’s up to today’s civil engineers to implement tighter requirements, higher performance, and lower costs, all while keeping the environment in mind.


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