Metals and plastics have long been rivals in the piping ring—a battle that's unlikely to end anytime soon as the economic downturn continues to drive efforts to cap costs.
And what's going on in southern Louisiana is probably not what the steel tubular industry wants to hear, nor is it likely to ease the rivalry as the plastic product makes deeper inroads.
The St. Charles Parish Waterworks Department is replacing an 8-inch cast iron water line, which had corroded and become clogged with deposits after 50 years of use. However, the 7,000-foot pipe won't be replaced with iron or steel, but instead with 12-inch C-900 polyvinyl chloride (PVC) pipe. The department also recently ran 7,000 feet of 24-inch polyethylene pipe under the Mississippi River, 145 feet below the river bottom.
"The majority of pipe being installed down here is this PVC pipe," said Todd Champagne, distribution construction technician at the Waterworks Department. "(Plastic) has less of a tendency to corrode and have calcium buildup. We do use some iron pipe in applications like roadway crossings where it has to hold up to traffic and weight."
The department has been using PVC pipe for the past 25 years, but as a result of growth in the area it's using even more than in the past, he said, noting that PVC is less expensive than steel and ductile iron while polyethylene is more expensive than the metal materials.
However, both plastics have advantages over metal, Champagne said, noting that the department has used PVC pipe up to 36 inches in diameter. "To bore through the earth to put in the PE (polyethylene) is $50 a foot on its own," he said. "But the plastic is flexible, lighter, it bends and turns, and there's no clogging."
The Pennsylvania Infrastructure Investment Authority (PennVest), which funds sewer, stormwater and drinking water projects throughout Pennsylvania, also has seen a variety of materials used in the water projects it funds.
Paul Marchetti, PennVest's executive director, said the community where the water lines are installed does the actual selection and purchasing of the material—from transmission mains to smaller water lines of all diameters.
Whatever the material, the state has spent far more money this year than in the past, primarily as a result of the American Recovery and Reinvestment Act, he said. "We normally approve $300 million per year in projects. But in the past six months (the state has) approved more than $900 million worth. We've done three years' work in six months."
Pennsylvania received $220 million in federal stimulus funding, and the state matched that and added more. However, Marchetti said he doesn't foresee this type of spending on water lines continuing. "I think we're probably going to get more back to business as usual," he said. "A large chunk of the approvals were in order to help with the stimulus. But I think at this point we won't do any more approvals until later this year."
Marchetti said project bids were coming in lower than expected, although he's not sure whether that was a result of less-expensive water line prices. "Generally they're coming in lower, but I can't exactly say that's attributable to the water lines themselves. We don't break it down that way."
In addition to spending more money this year, the state also got a lot more requests for funding, Marchetti said. "We got a lot more applications; a two-thirds increase in normal numbers."