Water Pipes Evolve to Stainless Steel
THE MAGAZINE DEVOTED TO NICKEL AND ITS APPLICATIONS
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DUCTILE IRON PIPES in this wellhouse on the University of Missouri campus in Columbia, Missouri, were
originally installed in 1938.
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THE SAME WELLHOUSE as the one pictured above, with new stainless steel piping.
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THIN-WALLED S30400 stailness steel pipe is easy to use and modify, reducing installation costs
significantly.
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Español
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The use of stainless steel piping for water distribution continues to expand in North America as
lower maintenance costs become a top priority.
By Virginia Heffernan
Nickel Magazine, March 2005 -- "The majority of cost in an underground utility project is associated with excavation," says Mathew Rice, senior staff engineer for the University of Missouri-Columbia’s (MU’s) Energy Management Department, which has been using S30400 stainless steel in some of its domestic water applications for the past five years. "Not to have to go back and fix pipe joints is a significant life cycle advantage."
The department, which provides an average of 7.6 million litres of water per day to the MU campus as part of an award-winning district energy system, has been gradually replacing some of its ductile iron and polyvinyl-chloride (PVC) pipes with stainless steel since 1999.
"We began by replacing our concrete-lined ductile piping with PVC," says Rice, "but we found that PVC offered limited strength when dealing with water lines in our expanding steam tunnel system."
The water distribution system serves 178 buildings on the campus, including hospitals, athletic complexes and research facilities, through five wells and 34 kilometres of underground piping ranging in size from 3 to 30 centimetres in diameter. Last year MU renovated the piping of one wellhouse built in 1938 using S30400 stainless steel and is planning to renovate another wellhouse in a similar fashion this year.
Rice says the thin-walled (schedule 10 or 20) S30400 stainless steel pipe is easy to use and modify, saves on construction costs, and gives a "food grade" appearance to the wellhouses that instills confidence in water quality among the campus community.
Eliminating the cost of cutting ductile iron pipe to size and installing additional joint restraints cancels out the higher capital cost of stainless steel.
"Due to the recurring challenges with leaks at PVC pipe restraints, it’s easy to see how welding a stainless pipe would save future maintenance costs," says Rice.
The S30400 stainless steel can withstand the regular disinfection treatments required under American Water Works Association (AWWA) regulations, provided the chlorine disinfectant is properly mixed in liquid rather than tablet form. It also complies with American National Standards Institute - National Sanitation Foundation (ANSI-NSF61) guidelines for drinking water quality.
The energy management team also uses stainless steel piping in the power plant’s water pretreatment facilities to prevent pipe corrosion. Stainless is also used in cooling towers that support the campus chilled water system, eliminating maintenance and performance problems associated with chip scale from mild steel piping.
They are also looking at using S30400 stainless steel mesh to capture coal dust and other small particles from storm water before it enters storm water drains. Rice says the team found that the steel mesh provides better screening and flow rates than conventional fabric filtration systems.
In 2004, the MU Energy Management Department won the "System of the Year Award" from the International District Energy Association for its high level of performance, including reliability, efficiency and energy conservation. Previous recipients of the award include Toronto’s Enwave District Energy Ltd., profiled in this magazine in July 2004.
Virginia Heffernan is a Toronto-based freelance writer.
PHOTOS: University of Missouri - Columbia
Mathew Rice |
