Understand that if the earthquake is sufficiently large, Mother Nature will always win. However, studies performed after several recent major earthquakes (Kobe, Japan - magnitude 6.9 - 1995, Northridge, CA - magnitude 6.7 - 1994, and Loma Prieta, CA - magnitude 7.0 - 1989) show that ductile iron piping systems suffered significantly less damage than other piping materials.

TR FLEX Telescoping Sleeves and XTRA FLEX®  high deflection fittings have often been used to cross fault lines to increase the survivability of the pipeline. When used for this purpose, the Telescoping Sleeve is installed only partially extended. A dirt boot of polyethylene encasement is taped securely to the sleeve and the mating pipe to prevent dirt from being forced under the gasket and breaking the seal. The pipeline must be carefully backfilled and compacted before applying any internal pressure. This ensures the sleeve will remain partially extended and only move with significant earth movement.

Depending on size, a TR FLEX Telescoping Sleeve that has been installed only halfway extended can accommodate up to one foot of expansion or contraction of the pipeline. This ability to expand/contract coupled with the ability of a standard TR FLEX Joint to deflect up to 5° or an XTRA FLEX Fitting to deflect up to 20° allows the pipeline to survive significant lateral movement when subjected to earth shear.

Yes, wrapping the TR FLEX® telescoping sleeve and TR TELE FLEX® coupling will prevent dirt from becoming impacted in the joint, and could prevent movement.

USP recommends that only flexible joints be buried  i.e. Mechanical Joint, TYTON JOINT® and TR FLEX®.

No. Usually, a pipeline flowing constantly maintains a fairly even temperature. TR FLEX® Pipe should always be extended at installation to engage the locking segments which provide joint restraint. When the joint is properly extended, there is sufficient clearance between the face of the pipe plain end and the back of the adjoining bell to accommodate slight changes in length due to thermal effects.

If a TR FLEX Telescoping Sleeve is installed above ground, internal pressure will usually extend the sleeve to its maximum length. In the case of a bridge crossing where the ends of the pipeline are usually fixed, the increase in length often causes the pipeline to snake. A zigzag pipeline is not only aesthetically not pleasing, it can also result in over-deflection at the joints.

The exception to this recommendation is where a pipeline is to cross a lengthy bridge that has been constructed in sections such that the roadbed has expansion joints between sections. Provided the individual pipe on each section are given adequate vertical and lateral support, it may be desirable to add a TR FLEX Telescoping Sleeve at each bridge expansion joint so that the pipeline can accommodate significant movement fo the roadbed.

Yes, it is possible, but it must be done very carefully.

In a standard TR FLEX joint, the locking segment cavity and gasket seat are adjacent to each other. The joint should be retracted to engage the locking segments, a distance that will vary by size but averages less than 3/4".

In a TR FLEX Telescoping Sleeve, the locking segments cavity and the gasket seat are separated by an appreciable distance (depending on size, this can be up to approximately one foot.) Similarly, the location of the weld bead on a plain end for Telescoping Sleeve is considerably further back from the face of the plain end than on a standard TR FLEX plain end. It is these design features working together that allow the collapse and expansion of the Telescoping Sleeve while maintaining a reliable seal throughout the range of longitudinal movement.

The TR FLEX GRIPPER® is used to accommodate field cuts of TR FLEX® Pipe. The Gripper Ring takes the place of both the locking segments and the factory applied weld bead, which would be cut off on a field cut pipe.

If it should be deemed necessary to install a Telescoping Sleeve with a Gripper Ring, it is important to consider two things:

1.  Once the Gripper Ring is tightened around the pipe installed in a Telescoping Sleeve, the ability for significant longitudinal movement is eliminated.

2.  Prior to tightening the Gripper Ring, it must be determined that the pipe has not been pulled out past the gasket, which would prevent achieving a seal.

One way to do this is to measure from the face of the Telescoping Sleeve to a point approximately one inch past the back of the gasket seat. Apply a band of duct tape around the circumference of the field cut pipe with the edge of the tape closest to the face of the plain end located at the distance measured. Insert the gasket and the Gripper Ring, lubricate the gasket and plain end of the pipe and insert the plain end until the edge of the duct tape is flush with the face of the bell. After ensuring the Gripper Ring is square on the pipe, tighten the torque-limiting bolts of the Gripper Ring until the heads snap off.

If at all possible, check to be sure that the gasket is in place and fully compressed between the inside of the Telescoping Sleeve and the outside of the plain end of pipe.