Like other flexible pipe materials, PVC experiences ring deflection in response to external loads. Two PVC Pipe News articles review the deflection-response mechanism. The first article is "Back to Basics: Time Dependent Variables for Flexible Sewer Pipe." The article reviews the key elements that determine the long-term ring deflection that a flexible pipe will experience. It will also show that the time-dependent elements do not include creep. The second article is "A More Typical Deflection Response."

EXTERNAL LOAD DESIGN CALCULATOR

Allows designers to easily determine long-term deflection of PVC pipe given specified embedment (backfill) and pipe material properties. Users can vary inputs such as pipe size, wall thickness, soil properties, live loading conditions and depths of cover.  PVC pipe has a long-term deflection limit of 7.5%.

This Uni-Bell Technical Report, "UNI-TR-1, Deflection: The Pipe/Soil Mechanism," details design procedures for predicting the long-term deflection of buried PVC pipe.

PVC Sewer Pipe Standards are summarized on a single sheet.

This Canada-specific comparison of PVC and polypropylene (PP) sewer pipes is based on: (1) For PVC sewer pipe – decades of research and field experience: (2) For PP’s new sanitary-sewer pipe – brief history of usage with unknown longevity.

ASTM standards limit ring deflection to 7.5%. The PVC Pipe News article, "Deflection: What Are the Limits?" looks at performance issues when ring deflection exceeds 7.5%.

How does ring deflection affect the hydraulic capacity of buried PVC sewer pipe? Read "The Effects of Deflection on Sewer Hydraulics, The Sequel," from PVC Pipe News.

Article and photo demonstrate how flexible PVC can be used in shallow bury applications.