Why Is Over Insertion Of Pipes At Joints Not Recommended?

If the joint is over assembled, in other words, the spigot is jammed into the neck of the bell, the flexibility of the joint is lost. Uneven settlement in the trench may cause an over assembled joint to leak – do not assemble beyond the reference mark. Proper assembly calls for insertion of the spigot end into the bell so that it is in contact with the gasket. Keep the pipe lengths in proper alignment. Brace the bell while the spigot end is pushed under the gasket, so that previously completed joints will not be further inserted. Push the spigot into the bell until the assembly mark on the pipe barrel is flush with the end of the bell. Stabbing is not recommended and should be avoided.

If undue resistance to insertion of the spigot end is encountered or the reference mark does not reach the flush position, disassemble the joint and check the position of the gasket. If it is twisted or pushed out of its seat, clean the gasket, bell and spigot end, reseat the gasket properly (using a factory installed gasket as a guide) and repeat the assembly steps. Be sure both lengths are in proper alignment during assembly. If the gasket was not out of position, measure the distance between the reference mark and the spigot end. If necessary, relocate the reference mark if it is out of position.

Lastly, there should be no axial deflection at the joint. Bending the pipe, rather than deflecting the joints, should serve to accomplish small changes in direction.