PVC PIPE GASKETED JOINTS


Unibell1158

Uploaded on Apr 24, 2020

Category Business

In the early days of the PVC pipe industry, pipes and fittings were connected by solvent-cemented joints. The first ASTM standards for this joining system were published in the mid-1960s. As pipe sizes increased, however, solvent-cementing became a less attractive option.

Category Business

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PVC PIPE GASKETED JOINTS

PVC PIPE ASSOCIATIONTECHNICAL BRIEF PVC PIPE GASKETED JOINTS — PART 1: HISTORY In the early days of the PVC pipe industry, pipes and fittings were connected by solvent-cemented joints. The first ASTM standards for this joining system were published in the mid-1960s. As pipe sizes increased, however, solvent-cementing became a less attractive option. Over the next decade, push-on gasketed joints were widely adopted as an alternative to cementing. Several ASTM standards for gasketed joints were published by the mid-1970s: • ASTM D3139 for pressure pipe (1973) • ASTM D3212 for non-pressure pipe (1973) • ASTM F477 for gaskets (1976) These standards are still in effect today, but are not the same as they were forty years ago. ASTM reviews all standards on a regular schedule, either reaffirming without change or revising as necessary. For PVC pipe, the popularity of bell-and-spigot gasketed joints can be attributed to the following: • Leak-free piping systems • Ease of installation • Dependability • Long service-life • Ability to accommodate both positive and negative (vacuum) internal pressures • Ability to accommodate ground movements caused by seasonal changes and seismic events • Ability to resist chemical attacks • Ability to prevent axial stresses by allowing longitudinal movement IMPROVEMENTS IN GASKETS The first gasketed-joint PVC pipes were sealed by a rubber o-ring that was manually inserted into a pipe or a fitting. Over time, this simple ring was modified and improved many times. Newer designs incorporate multiple sealing methods including self-restraint systems, locked in place, integrated gaskets, and dual durometers. The impetus for the improvements included: • To reduce insertion forces during pipe assembly, resulting in increased worker productivity at relatively low cost • To lessen the chance of a gasket being dislodged during pipe assembly, reducing jobsite problems • To better accommodate variations in joint geometry, permitting proper sealing over a wide range of conditions • To better accommodate extreme conditions like ground movement and joint deflection, allowing the pipe system to function in adverse situations THE BOTTOM LINE: LEAK-FREE WATER AND SEWER PIPELINES Elastomeric gaskets have been used for sealing PVC bell-and-spigot push-on joints for about fifty years. During that time, more than two million miles of leak-free water and sewer pipelines have been installed across North America. References: ASTM D3139 “Standard Specification for Joints for Plastic Pressure Pipes Using Flexible Elastomeric Seals”; ASTM D3212 “Standard Specification for Joints for Drain and Sewer Plastic Pipes Using Flexible Elastomeric Seals”; ASTM F477 “Standard Specification for Elastomeric Seals (Gaskets) for Joining Plastic Pipe”; Rahman, S. “Sealing Our Buried Lifelines” AWWA Opflow, (April 2007). Uni-Bell PVC Pipe Association | 201 E. John Carpenter Freeway, Suite 750 | Irving, TX 75062 Phone: (972) 243-3902 | Fax: (972) 243-3907 | [email protected] 5.16.2019