Market Report
Rising to the
Challenge W
hat comes to mind when you think of ductile iron pipe? Maybe it’s
toughness and how it can withstand the most challenging conditions and thrive. Maybe it’s the durabil- ity and how it can last generations. Or maybe it’s innovation, with new and interesting additions coming frequently to improve the value of the product. In fact, all of those would be true. “It is tough in any service condi-
tion,” said Maury Gaston, manager, marketing services, AMERICAN Ductile Iron Pipe (Birmingham, Ala- bama). “It can withstand all installa- tion environments, rocky trenches, soft trenches, aggressive handling. While we may not recommend aggressive handling, underground utility con- struction is a demanding environment and ductile iron has the toughness to withstand that.” Manufactured via centrifugal cast- ing, ductile iron pipe was introduced
36 | MODERN CASTING December 2016
to the marketplace in the 1950s as a replacement and improvement of older gray iron. Ductile iron contains a magnesium additive that makes it stronger and more flexible, which enables it to withstand even greater stresses and loads. In addition, modern ductile iron pipe is cement lined, which eliminates tuberculation, a process that might restrict the flow in older, unlined pipe. “The older gray cast iron pipe that ductile iron replaced was first installed in the early 1800s, and thousands of miles of gray iron pipe continues to serve reliably after more than 100 years of ser- vice,” said Jeff Otterstedt, executive vice president, McWane Ductile. “Modern, cement-lined ductile iron can be expected to last even longer, even in corrosive soils when protected by polywrap. That’s a proven track record that no other material can match.” In 1958, LaFourche Parrish
(Louisiana) was the first municipal-
Ductile iron pipe is able to withstand the test of time while being a viable choice for environmental and efficiency reasons. BRIAN SANDALOW, ASSOCIATE EDITOR
ity to install ductile iron pipe with a polyethylene encasement. It’s an 8-mm loose polyethylene fill that’s wrapped around the pipe. And it’s thriving 58 years later. “We looked at it last in 2013
after 55 years of service. We go back at that location every five years and expose a length of the pipe and peel back the polyethylene encasement, examine the pipe for corrosion, and test the fill to see what its physicals are. So far so good,” said Gregg Horn, executive vice president, Ductile Iron Pipe Research Association (DIPRA). “We’ve looked at it about half a dozen times now over the years and haven’t seen any evidence of corrosion under the wrap. Te film is a good strong film that is protecting that pipeline.” More recently, the industry has
built on the polyethylene encase- ment with the introduction of the V-Bio polyethylene encasement for corrosion control of underground pipes. It builds on the polyethylene encasement and adds corrosion
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