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.

Q & A on Max Test Pressure of Installed PVC Pressure Pipe

Feb 22, 2017  John Houle

Question – one question that I hear quite often about testing of installed PVC pressure pipe is: “What is the maximum test pressure I can use?” Answer – since every component of a pressure pipeline has a pressure rating, the simple reply is: Do not exceed the pressure rating of any of the pipeline components.

PVC Pipe Cyclic Design - AWWA

Feb 8, 2017  John Houle

AWWA first included cyclic design for PVC pipe in the 2007 edition of the C900 standard. The same method was later incorporated into the C905-2010 and the C900-16 standards.

Manning's "n" for PVC Gravity Sewer Pipe

Jan 12, 2017  John Houle

“Conservative” design is taught continually to all engineers during college and throughout their employment. I think we can all agree that this is a good idea – we don’t want engineers to cut corners and cause potential problems.

PVC Pipe Bell Direction

Dec 8, 2016  John Houle

Questions sometimes arise about which way the bell should be positioned in a PVC pipeline. Typically there are two concerns: 1. Does bell direction make a difference in pipeline hydraulics? 2. Does it make a difference during installation?

Safety Considerations for Air-Testing of PVC Sewer Pipes

Sep 29, 2016  John Houle

Occasionally I hear a report about safety issues with air-testing of sewer pipes. The story usually starts with “An end-plug let go.” There was a sudden whoosh of air out of the manhole that had potential consequences for nearby personnel.

An Engineering Primer on AWWA C900/C905 PVC Pipe

Sep 16, 2016  John Houle

Engineers who are unfamiliar with PVC pressure pipe sometimes have a list of questions about the product. These questions, which often arise from misinformation propagated by competitive materials, usually have logical answers based on engineering principles.

New PVC Pressure Pipe Tapping Guide

Jun 22, 2016  John Houle

The PVC Pipe Association has re-issued its “Tapping Guide.” The new guide includes additional diagrams and photos, as well as expanded text — all in a more logical, readable format.

Installation of PVC Pipe into a Mechanical Joint (MJ)

May 25, 2016  John Houle

Installation of PVC pipe into mechanical joint (MJ) appurtenances is a very common occurrence in North American municipal pressure pipelines. Problems with MJ connections can be minimized if proper installation techniques are used.

Making Sense of Diameter Types for PVC Pipe

Apr 4, 2016  John Houle

There are many different outside diameter (OD) types used for PVC pipe for various pressure and non-pressure applications. Not only are there several OD types, there are also associated abbreviations to add to the mix.

Guide for PVC Sewer Fittings and Laterals

Feb 22, 2016  John Houle

Uni-Bell has recently published a new document titled, Design and Installation Guide – PVC Fittings and Laterals for Solid-Wall PVC Sewer Pipe. The guide provides information on appropriate system design and proper installation of PVC fittings products where solid-wall PVC pipe is used in non-pressure applications.