U.S. Pipe TR-Flex Restrained Push-On Joint
Pipe and Fittings Suggested Specification


When joint restraint for a 4" through 64" push-on joint pipe installation is required and indicated in the 
project plans and specifications, restrained joint pipe and fitting utilizing ductile iron components shall be 
provided.

Restrained joint pipe shall be ductile iron manufactured in accordance with the requirements of ANSI/AWWA
C151/A21.51.  Push-on joints for such pipe shall be in accordance with ANSI/AWWA C111/A21.11 "Rubber
Gasket Joints for Ductile-Iron Pipe and Fittings."  Pipe thickness shall be designed in accordance with ANSI/
AWWA C150/A21.50 "Thickness Design of Ductile-Iron Pressure Pipe," and shall be based on laying 
conditions and internal pressures as stated in the project plans and specifications.

Restrained joint fitting and the restraining components shall be ductile iron in accordance with applicable 
requirements of ANSI/AWWA C110/A21.10 and/or C153/A21.53 with the exception of the manufacturer's 
proprietary design dimensions.  Push-on joints for such fittings shall be in accordance with ANSI/AWWA 
C111/A21.11.

Restrained joint pipe and fittings shall shall be U.S Pipe's TR-FLEX Pipe and Fittings or approved equal.  
Restraint of field cut pipe shall be provided with U.S. Pipe's TR FLEX GRIPPER® Ring, TR FLEX Pipe field 
weldments or approved equal.

Fittings with fusion bonded coatings shall be supplied in accordance with ANSI/AWWA C116/A21.16, 
Protective Fusion-Bonded Epoxy Coatings for the Interior and Exterior Surfaces of Ductile-Iron and 
Gray-Iron Fittings for Water Supply Service.  Cement mortar lining and seal coating for pipe and fittings, 
where applicable, shall  be in accordance with ANSI/AWWA C104/A21.4.  Asphaltic outside coating shall 
be in accordance with ANSI/ AWWA C151/A21.51 for pipe and ANSI/AWWA C110/A21.10 or ANSI/AWWA 
C153/A21.53 for fittings.

Restrained push-on joints for pipe and fittings shall be designed for a water working pressure of 350 psi for 
sizes 4" through 24", 250 psi for sizes 30" through 48", and 150 psi for sizes 54" through 64".