Technical Blog

Welcome to John’s Blog. Answers to frequently asked questions are periodically posted here. The objective is to share information about PVC pipe with readers as well as with utilities, design engineers and pipe installers. The blog provides the latest information on PVC pipe design, installation, and application for water and wastewater infrastructure projects.

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John Houle: Senior Technical Consultant, PVC Pipe Industry

John Houle holds a Master’s Degree in Civil Engineering from the University of Missouri and an MBA from the University of Oregon. He has more than 25 years of experience in the plastic pipe industry in applications engineering, market development, forensic analysis, technical writing, and standards development.

Important Considerations When Comparing PVC and Ductile Iron Pressure Pipe

Posted By John Houle on Nov 13, 2013

The Decline of Iron Pipe

During 60 years of sustained growth for PVC water pipe, iron pipe’s market share has decreased dramatically. The iron industry has reacted by negative attacks and by spreading misinformation about PVC pipe. I think it is time to provide more balanced information.

PVC Pipe – Healthy and Safe

PVC is used in over 40,000 municipalities in North America because it meets health and safety regulations – some 10 million quality tests have been conducted on water carried through PVC pipe since it was introduced. Health and safety are major reasons why most new installations of drinking-water distribution pipe are PVC.

Why the Move from Iron to PVC?

The major cause: corrosion of iron pipe. To make matters worse, thinner-walled ductile iron (DI) corrodes sooner than traditional cast iron pipe products.

Transitioning from Iron to PVC Pipe: A Smooth and Seamless Process

The DI industry has argued that the transition to PVC is so difficult it would be better to stay with underperforming iron. In fact, the typical move to PVC has been very straightforward:

• Same outside diameters – for the municipal water market, PVC pipe and DI pipe are manufactured in the same cast-iron outside diameter regimen.

• Same fittings, valves, and appurtenances – the same slip-on or mechanical joint fittings, valves, and appurtenances used with DI can be used with PVC pipe in the same manner. This ensures that product styles and installation procedures will be familiar to the waterworks professional.

• Same suppliers – all items needed for PVC water systems are available from the same suppliers that provide DI items.

Comparison Sheet

Attached is a comparison sheet that addresses important issues in water pipe selection and serves as a quick reference for comparing PVC and DI pressure pipe. Click here to read.