When plastic is more than concrete: Texas town tries HDPE pipe in stormwater applications
A small Texas town about 25 miles northeast of Corpus Christi, whose sewers used to be all concrete, is now among those that have discovered an alternative pipe material to move storm water...
ARANSAS PASS, TX, Nov. 15, 2004 -- A small Texas town about 25 miles northeast of Corpus Christi, whose sewers used to be all concrete, is now among those that have discovered an alternative pipe material to move storm water.
The main access road to the high school and a major street for draining storm water in Aransas Pass, Texas, now has thousands of feet of high-density polyethylene (HDPE) pipe underneath it.
"For the conditions we had with this project, the water tight HDPE pipe was the only way to go," said contractor Tommy Fox, of J.J. Fox Construction. "This area has typically been a place where they used reinforced concrete pipe (RCP). But the RCP joints just won't hold up if you don't have good solid backfill."
That's what happened to the RCP pipe that Fox replaced earlier this year on Deberry Street in Aransas Pass. The RCP pipe didn't perform well in the native sandy soil and high groundwater table. The bell-and-spigot joints began to fail.
Because of the poor RCP joints allowed infiltration of the surrounding soil, the road was constantly riddled with potholes. Eventually, the road lost support and the storm water had to find a new route.
"We pulled out the old RCP and the HDPE pipe installation was very smooth," Fox said.
Fox installed 1,300 feet of 60-inch corrugated HDPE pipe; 1,300 feet of 48-inch pipe and 2,000 feet of 36-inch pipe. The pipe featured watertight joints was supplied by a Plastics Pipe Institute (PPI) member company.
The watertight pipe's ceramic/polymer composite joint combines with HDPE's abrasion and corrosion resistance to produce a joint with excellent strength. The wide ceramic/polymer composite is fused to the outside wall of the built-in bell, improving the joint's integrity and tolerance control.
With its integral built-in bell and factory-installed gasket, the pipe requires no extra couplers, grout or other sealants to install. The joint meets or exceeds ASTM 3212 lab test and ASTM 1417 watertight field test, which helps fill an essential role in meeting the new, stricter Environmental Protection Agency guidelines.
"Markets like Texas with its sandy soil are really starting to find out that the watertight joints of HDPE pipe can be an advantage for them," said Jeff Hiott, applications engineer for PPI. "It's simply a matter of a few places like Aransas Pass having success, and the news will spread."
PPI reports that, two years ago, the polyethylene pipe industry produced nearly one billion pounds of pipe. The specification and use of dual wall corrugated PE pipe for storm water is skyrocketing, PPI says, based on factors such as total installed cost, enhanced hydraulic flow and chemical and abrasion resistance when measured against other materials.
Across the country in New York, research data from the New York State Department of Transportation shows that it used PE pipe for 56 percent of its roadway projects as of 2001 -- nearly double the amount of concrete pipe. According to the research, it was 15 years ago that concrete pipe could boast numbers as high as that.
Statistics like this help show that thinking ahead and considering the actual cost of a project over its useful life are beginning to receive much more consideration by owners and engineers. Lifecycle costing is a well-documented process that calculates not only the initial installed cost of a pipeline or other system component, but also accounts for the other associated costs attributable to ongoing maintenance, repair and operations during its expected life.
"There is a billion dollar pipeline rehabilitation industry out there that benefits from shortsighted thinking, where only the initial low dollar cost of a pipeline material is considered, and not what additional costs may be required in the future," said Mark Wallbom, senior vice president of the contracting firm Miller Pipeline Corporation. "Much of the pipeline rehabilitation work we do, using pipebursting, internal joint sealing, HDPE slip-lining, and/or cured-in-place lining is in failed concrete and corrugated metal pipelines," Wallbom added.
Rich Gottwald, president of PPI, says corrugated polyethylene pipe is routinely chosen for a variety of projects because of the pipe's structural design capabilities, service life and long-term performance.
"It says a lot about our product when public works engineers are increasingly choosing our product for such a wide range of applications," said Gottwald.
Technical reports available at PPI's website (www.plasticpipe.org) explain how the engineered corrugated exterior of polyethylene pipe works with the backfill envelope to provide high pipe system strength no matter what the application.
The Plastics Pipe Institute is the major trade association representing all segments of the plastics piping industry. Member companies share a common interest in broadening market opportunities that make effective use of plastics piping for water and gas distribution, sewer and wastewater, oil and gas production, industrial and mining uses, power and communications duct and irrigation.