Prohibitive Procurement
A solution to corrosion exists. Newer materials like corrosion-proof plastic pipe (PVC) are available. Unfortunately, prohibitive procurement practices by municipalities are hindering its wider use in eastern Canada and throughout the US.
Municipalities that have embraced this technology have achieved dramatic results. In 1978, Calgary adopted a more open procurement policy allowing PVC. As a result, half of its 4,000-kilometer water distribution system now consists of that material. Its water main break rate, at 0.2 per 100 kilometers, is the lowest in Canada. By making extensive use of PVC, Calgary and Edmonton save an estimated $5 million a year in water main repair costs. But this is only part of the savings. The biggest financial benefit will come from lower replacement costs over the long term. If Canadian municipalities adopted the Calgary approach nation-wide, taxpayers could save hundreds of billions of dollars in the future.
Traditional pipe materials are not only subject to corrosion; they also tend to leak more because their joints are not as watertight as PVC. Montreal is a case in point: about 40% of the water pumped through its underground network is lost due to water main breaks and leaky pipes.
A study presented at a worldwide pipe symposium in Milan reported that vinyl pipe installed 70 years ago in Germany could easily see its 170th anniversary. Additionally, PVC's ultra smooth surface means that less energy is required to pump water from source to tap.
Yet some water utilities have failed to take full advantage of PVC pipe in all sizes. While most municipalities in Canada allow PVC in diameters of 12 inches and smaller, those in eastern Canada prohibit its use in larger sizes. In the US, smaller PVC is permitted in about 50% of municipalities, while larger plastic pipe is more widely excluded. Use of small diameter PVC has helped North American water utilities keep water main breaks from getting further out of control. However, its use in large diameters must be increased if other municipalities are to emulate Calgary's success.
No doubt, using larger PVC pipe would reduce the Region of Durham's water main break rate of 8.7 per 100 kilometers, Peel Region's rate of 10.9 and Toronto's rate of 26.9.
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Life-cycle Costs and Corrosion
