Ductile Iron Pipe vs. PVC
Engineers have long supported Ductile iron pipe’s superior durability and high quality when compared to PVC pipe.
Advantages of Ductile over PVC
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Ductile iron pipe has more than 13 times the impact strength, nine times the tensile strength and four times the burst strength of PVC pipe.
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Ductile iron pipe can handle stress. Under stress, PVC failure is a matter of time; and the more stress that is applied, the sooner it will fail.
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PVC pipe's longevity depends on stress and time—the greater the stress, the sooner it will fail. Ductile iron’s strength is not compromised over time.
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The cost to pump water through PVC pipe is as much as 38% more expensive than that of Ductile iron pipe, increasing life cycle costs and releasing more greenhouse gases.
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PVC pipe is made from petrochemicals in a process that can be harmful to the environment and human health. Ductile iron pipe is made from recycled steel and iron is manufactured to the industry’s most rigorous and conservative standards.
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PVC production releases dangerous chemicals, including vinyl chloride, dioxin and ethylene dichloride.
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PVC pipe is sensitive to ambient temperatures (I.e., in low temperatures, PVC becomes increasingly brittle and can break more easily, while in warmer environments, PVC becomes weaker).
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PVC pipe cannot withstand relatively minor scratches, and extra care must be taken to avoid large rocks, frozen lumps and debris during installation. A scratch no deeper than the thickness of a dime can ruin an entire length of PVC pipe.
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Ductile iron pipe is not affected by temperature changes. PVC pipe becomes brittle in colder temperatures and weaker in higher temperatures.
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PVC pipe can lose 34% of its impact strength from exposure to the sun in about one year, which has no impact on Ductile iron pipe.
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Direct tapping of Ductile iron pipe is easier, safer, less expensive, faster and less likely to damage the pipe than PVC tapping. Tapping PVC pipe can result in cracked pipes, injured workers and costly flooding until the repairs can be made.
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Because Ductile iron is made with metal, locating it underground is effortless. Locating a leak in PVC pipe is extremely difficult. Most locating techniques involve transmitting sound waves down the pipeline, that do not travel well in plastic pipes.
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PVC pipe requires installing locating wires in the trench when the pipe is lowered into the ground—an added cost.
