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.

Design Factor and Safety Factor Explained

Posted By John Houle on Oct 16, 2013

There has been confusion recently in the plastic pipe industry regarding the terms “design factor” (DF) and “safety factor” (SF).

Mathematically, the relationship is simple: DF is the inverse of SF. At least three AWWA standards state explicitly in the definition for DF that design factor is “the inverse of the safety factor.”

The attached technical brief discusses the relationship between the two concepts in more detail. To further illustrate the point, the brief includes a table of numerical examples from AWWA product standards for plastic transmission/distribution pipe. In all cases the design factor is 0.50 and the safety factor is 2.0.

Click here to read.