TR FLEX® Restrained Joint Fittings

To accommodate traditional open trench projects, as well as horizontal directional drilling (HDD) applications, the TR FLEX®  line of products is a flexible and reliable option. Easily disassembled. Sizes 4" - 24" suitable for 350 psi working pressures; 250 psi working pressures for 30" - 36". Perfect for HDD applications.

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  • TR FLEX® Ductile Iron Pipe and Fittings

    Restrained Joint Ductile Iron Pipe and Fittings

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  • Field Cutting & Welding for TR FLEX® Pipe

    Pipe installations may require field cutting, particularly where fittings are used. By planning ahead, many field cuts can be made in the portion of the line involving standard TYTON JOINT® Pipe thus eliminating the need to field weld the TR FLEX Pipe.

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Product Information

Product Information
TR FLEX® Ductile Iron Pipe Product Animation
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Product Information
Horizontal Directional Drilling with TR FLEX® Pipe
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FAQs // TR FLEX® Restrained Joint Fittings

Repair is achieved by first cutting out the defective or damaged lining to the metal so that the edges of the lining not removed are reasonably perpendicular to the pipe wall or slightly undercut. A stiff mortar is then prepared, containing not less than one part of cement to two parts of sand, by volume. This mortar is applied to the cutout area and troweled smooth with adjoining lining. To provide for proper curing of patches by preventing too rapid of a moisture loss from the mortar, the patched area is normally seal-coated immediately after any surface water evaporates, or alternatively the area is kept moist (e.g. with wet rags or burlap over the area or with the ends of the pipe or fitting taped over with plastic film, etc.). Of course, in potable water-related applications, no patch or curing components should be used in the repair that would negatively affect health or water quality.

There are many variables that determine the length of pull. The type of soil, size of equipment, amount, concentration and viscosity of the bentonite in the drilling mud are just a few of the variables that can determine the length of the pull. The longest pull to date was 2120 feet of 12” TR FLEX® pipe.

Soil conditions can vary widely and change dramatically within the length of the intended pull, it is for this reason that consideration be given to take soil samples at regular intervals along the intended bore-path at the depth of the bore. This information would enable the drilling operator to adjust the bentonite mixture, viscosity and add any other stabilizing additives as per the bentonite manufactures recommendations.

Double poly-wrap is recommended either with the first layer being the low-density poly with high-density over the outside or double wrapped with low-density.

Spiral winding is easier to do in a muddy trench and also does not allow the drilling mud to build-up underneath the poly-wrap causing it to balloon. All over-lapped edges of the poly-wrap should be taped except for the over-lapped poly along the length of the barrel, where the spiral winding is sufficient.

Double thickness cement mortar lining in accordance with ANSI/AWWA C104/A21.4, Section 4.7.2., with seal coat in accordance with section 4.11. The cement in the cement mortar lining shall conform to ASTM C150, Type V. The internal joint areas coming in contact with the seawater, the "wetted areas", should be coated with Induron PE-54 epoxy or they can be wrapped with Denso tape. Denso tape can be purchased through DENSO NORTH AMERICA, INC. in Houston, TX - Phone No. 281-821-3355 or

Yes. The TR FLEX® joint is easily disassembled by following the assembly instruction found in our TR FLEX® Pipe and Fittings brochure. The FIELD LOK 350® gasket requires a disassembly kit that can be purchased through your U.S. Pipe Representative.

If possible, the pipe can be inserted to make–up the joint, after assembly the jack can be removed. If the pipe will be inserted into a Mechanical Joint bell, the gland can be slid over the end to hold the pipe round while the joint is made. TYTON JOINT® and TR FLEX® bells are designed to round the pipe as long as the pipe will start into the throat of the bell. Once the pipe is pushed past the gasket it will seal.

Gripper rings can be used to complete closures and are not recommended for use in the pulling/pull back process.

This information can be found in U.S. Pipe's guide Safe Packaging and Shipping and also the Installation Guide for Ductile Iron Pipe, published by the Ductile Iron Pipe Research Association (DIPRA). Copies can be obtained from your local U.S. Pipe Sales Representative.