Ductile Iron Pipe Hazen-Williams Flow Coefficient Declines Over Time

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.

Organotin (Tin) Stabilizers - Not a Health Concern for PVC Pipe

Mar 25, 2019  John Houle

PVC pipe’s organotin stabilizers — not a health concern.

PVC Pipe Accommodates Dynamic Ground Movement

Mar 12, 2019  John Houle

PVC pipe — an excellent choice for ground-movement situations

Sample Specifications for PVC Water and Sewer Pipes

Feb 25, 2019  John Houle

The Uni-Bell PVC Pipe Association has recently published sample specifications for water and sewer pipes.

New Guide for PVC Pressure Fittings

Feb 12, 2019  John Houle

PVC pressure fittings — guide for design and installation.

Guide: Field-Cutting of PVC Pipe

May 2, 2018  John Houle

PVC Pipe Association's guide for safe and effective field-cutting of PVC pipe.

Proper Installation of PVC Piping

Apr 3, 2018  John Houle

Installation practices for underground infrastructure can play an important role in the performance of pipe networks.

Technical Paper: Evaluating Life Cycle Assessments for Underground Infrastructure

Feb 21, 2018  John Houle

Sustainable Solutions Corporation (SSC) paper on the importance of using transparent and verifiable standards when determining the environmental impacts of a pipe product. No other pipe material has disclosed environmental impacts to as transparent and regulated a degree as the PVC pipe industry.

Ductile Iron Pipe’s Hazen-Williams Flow Coefficient Declines Over Time

Jan 23, 2018  John Houle

The Ductile Iron Pipe Research Association (DIPRA) states that ductile iron (DI) pipe does not experience a decline in hydraulic performance over time. However, the very document that makes this statement is full of data that contradicts the claim.

AWWA Standards for PVC Pipe - Product Testing

Jan 9, 2018  John Houle

AWWA standards for PVC pipe have been around since 1975. These standards are developed by committees comprised of three groups: • Product user members (water utilities) • Product manufacturer members • “General interest” members (from consulting engineers, certifying agencies, etc.)

PVC Pipe and Fittings Materials – Testing Requirements

Dec 6, 2017  John Houle

In my three decades in the PVC pipe industry, I have noticed that many design engineers and utility personnel are surprised when they learn about the testing regimen that is followed by PVC pipe manufacturers.