Ductile Iron Compared to Steel Pipe
Ductile iron pipe’s advantages in field adaptability, corrosion control, and pipe wall thickness make it far superior to steel pipe substitutes.
Advantages of Ductile Over Steel
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Ductile iron pipe is typically manufactured with larger inside diameters than steel pipe, resulting in lower pumping costs–and an average 21% savings in energy costs.
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While both types of pipe may have the same yield strength, steel pipe can be 35% thinner and does not include similar allowances in design calculations that Ductile iron pipe design has.
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Installing steel pipe requires bonded coatings for corrosion control—either a cement-mortar coating or a bonded coating such as a tape-wrap. It is practically impossible to install steel pipe with bonded coatings without experiencing some coating damage from shipping and handling. Ductile iron pipe is routinely protected from corrosion through polyethylene encasement, which is applied at the job site—eliminating any shipping and handling problems.
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During installation, steel pipe is not stiff enough or strong enough to stand on its own. Braces must be placed inside the pipe to hold its shape.
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Steel pipe requires more side fill soil support against the external loads they will experience, increasing the difficulty of installation.
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Ductile iron pipe has push-on joints that can be used to reroute the pipe, offering installers more field adaptability and flexibility and eliminating the need for line drawings necessary for steel pipe installation.
