Flex-Ring® Joint

AMERICAN Ductile Iron Flex-Ring® Joint Pipe
Centrifugally Cast for Water, Sewage, or Other Liquids

4"-12" Flex-Ring® Joint		14"-48" Flex-Ring® Joint

AMERICAN Flex-Ring® Restrained Joint Ductile Iron pipe, utilizing the sealing features of the time-proven Fastite® Joint and a boltless restrained connection, provides flexible, easily assembled, positive restraint against endwise separation due to thrust.

The patented¹ Flex-Ring Joint is designed for a working pressure² equal to that of the pipe or up to 350 psi in sizes 4"-24" and up to 250 psi in sizes 30"-48". The joint has been thoroughly factory tested to withstand dead-end thrust resulting from more than twice those working pressures.

Flex-Ring® joint pipe with its positive, flexible joint restraint may also be used in trenchless applications such as horizontal directional drilling and pipe bursting. With spigot ahead, the low-profile Flex-Ring® bell assembles quickly and offers a smooth transition during pipe pull-back. AMERICAN offers a Flex-Ring® pulling bell assembly specifically designed for this installation method.

Pulling Bell Assembly 

For 4"-12" sizes, a beveled ductile iron, welded-on retainer ring and a ductile iron split flex-ring, assembled behind the retainer ring, provide the means of restraint. After the plain end of the pipe is assembled into the Flex-Ring bell, the split flex-ring is inserted and springs into the socket locking groove. The flex-ring is securely positioned behind the welded-on retainer ring and in the socket locking groove on the inside of the pipe bell. This provides the flexible restraint.

For 14"-48" sizes, a shop-applied weld bead and a rubber-backed ring, containing yellow painted ductile iron segments, provide the means of restraint. As the plain end of the pipe is fully assembled into the bell, the ductile iron segments automatically close on the pipe behind the weld bead. The enclosure of the segments between the weld bead, spigot, and the sloped inner lip of the bell provides the flexible restraint.

The Flex-Ring Joint can be safely deflected after assembly to the limits shown in Table Nos. 9-1 and 9-2. This liberal deflection facilitates installation, decreases the number of necessary fittings, and accommodates settlement.

Flex-Ring® Joint 4"-12" Standard Dimensions and Pressure Ratings

ADIP Table No. 7-19

Notes:
* Working pressure is the maximum pressure rating of the joint and is based on its capability to resist thrust due to internal pressure. If higher working pressure is required, check AMERICAN.
** Laying length is nominal 20'. Where exact lengths are required, contact AMERICAN. Minimum laying lengths for Flex-Ring & Flex-Ring End pipe is 1'0" and for Flex-Ring End & Flex-Ring End pipe is 2'0".
+ Dimensions subject to change at our option. Check AMERICAN if smaller or exact dimensions are required.
++ Intended for Horizontal Directional Drilling (HDD) applications. Flex-Ring pipe may be available for greater pulling loads than indicated in the tabulated values. Contact AMERICAN when higher pulling loads are required.
^ Approximate radius of curve produced by a succession of 20' lengths of pipe fully deflected.
^^ Based on weight of empty (full of air) Pressure Class 350 Flex-Ring pipe with standard cement lining immersed in water. Positive numbers indicate such pipe will float.

Flex-Ring® Joint 14"-48" Standard Dimensions and Pressure Ratings

ADIP Table No. 7-20

Notes:
* Working pressure is the maximum pressure rating of the joint and is based on its capability to resist thrust due to internal pressure. If higher working pressure is required, check AMERICAN. Pressure rating of the joint is limited by the pressure rating of the parent pipe.
** Laying length is nominal 20'. Where exact lengths are required, contact AMERICAN.

+ Dimensions subject to change at our option. Check AMERICAN if smaller or exact dimensions are required.
++ Intended for Horizontal Directional Drilling (HDD) applications. The tabulated values are based on Pressure Class 350 pipe thickness. Contact AMERICAN when it may be desirable to use lesser pressure class pipe or when higher pulling loads are required. Flex-Ring pipe may be available for greater pulling loads than indicated in the tabulated values.
^ Approximate radius of curve produced by a succession of 20' lengths of pipe fully deflected.
^^ Based on weight of empty (full of air) Pressure Class 350 Flex-Ring pipe with standard cement lining immersed in water. Positive numbers indicate such pipe will float.

The Flex-Ring Joint is Underwriters Laboratories listed and Factory Mutual approved in sizes 4"-12". This UL listing and FM approval applies to all pressure classes and special thickness classes of ductile iron pipe.

The only joint components needed to assemble the Flex-Ring Joint are a gasket and a single ring.

No loose lugs, heavy wedges, rubber tubes, etc. are necessary. Also, there is no need to orient bells to ensure proper installation, though for convenience, most installers orient the split locking ring ends in 4"-12" sizes away from the very bottom of the joints. Just follow the simple instructions shown on the following pages, and positive restraint is ensured.

Flex-Rings, Flex-Ring segments, and retainer rings are manufactured of ductile iron compatible with pipe. Welds and weld beads (if used) are nickel-iron, proven desirably cathodic to the ductile iron pipe, and welding is performed using welders qualified to produce high-quality, dependable welds.

Fittings for use with 16"-48" Flex-Ring pipe are ductile iron and meet or exceed the applicable performance and manufacturing requirements of ANSI/AWWA C110/A21.10 or ANSI/AWWA C153/A21.53. These are rated for the same working pressures shown for like fittings in C110 and C153. Fittings in these sizes are also available in both bell-bell and bell-Flex-Ring spigot configurations for installation versatility and economy.

AMERICAN Flex-Ring® pipe and fittings are normally furnished with standard asphaltic coating outside and cement lined in accordance with ANSI/AWWA C104/A21.4. Special coatings and linings can be furnished when specified.

Field closures or other restraint can normally be securely made by using AMERICAN's Fast-Grip® gasket, which is available in 4"-30" sizes. (See Fast-Grip gasket description for details.) The Fast-Grip® gasket restraint closure is UL listed and FM approved for use in Flex-Ring and Fastite bells in 4"-16" sizes. Field closures or other restraint in 14"-36" sizes can also be made in Flex-Ring bells only by using AMERICAN's Field Flex-Ring®. (See Field Flex-Ring description.)

¹ U.S. Patent Nos. 4,643,466, 4,685,708 and 5,197,768
² If higher working pressures are required, check AMERICAN.