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Correct Assembly of Gasketed PVC Pipe
Maximizes Joint Performance
 Gasketed
PVC Pipe: The Importance of Insertion Lines
Many pipe installers think that a PVC pipe spigot is correctly installed if its
insertion line has disappeared into the pipe bell. They believe that the purpose
of the line is to ensure that the spigot has been installed far enough to allow
the gasket to seal properly. This is only partly correct.
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The first purpose is to ensure that the gasket will properly
engage with the spigot to form a leak-free joint. If there
is a space between the line and the bell, sealing may be
affected.
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The second reason is to prevent the spigot from being
inserted too far into the bell. If the line is not visible,
the spigot has been over-inserted.
Thus, the insertion line is barely visible in properly installed PVC pipe. As
the technical brief, “Gasketed PVC Pipe: The Importance of Insertion Lines,”
explains (click
here), there is more than one purpose for the insertion line. Over-insertion
is not ideal because it defeats some of the benefits of PVC pipe joint design.
Expansion Gaps for Gasketed PVC
Pipe: Maximizing Joint Performance
 With
correct installation, there is a horizontal gap inside the joint between the end
of the spigot and the shoulder of the bell. The gap occurs in both pressure and
non-pressure pipe, but is observable only during video inspection of
gravity-flow sanitary sewer pipe. The gap is necessary to provide room for
thermal expansion of the pipe and to allow for angular joint deflection that
accommodates any ground movement that occurs. The gap is an integral feature of
the joint design and does not affect the joint’s water-tightness or its
hydraulic characteristics.
Click here to read the technical brief, “Expansion Gaps for Gasketed PVC
Pipe: Maximizing Joint Performance.”
Sixty years of experience have shown that PVC pipe joints function reliably
long-term even when not installed perfectly. However, the recommendations of
these technical briefs should be followed to maximize joint performance.
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Regards,
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John F. Houle, P.E.
Senior Technical Consultant, PVC Pipe Industry
201 E. John Carpenter Freeway, Suite 750 | Irving, TX 75062
T. 972.243.3902 | F. 972.243.3907
www.uni-bell.org
  
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