Expansion Joints

U-Flex Flexible Connector: Absorbing Building and Seismic Movement

See how U-Flex (Omega) flexible connectors use a U-shaped loop to absorb movement in every direction at building expansion gaps and during earthquakes.

ORFA Technical TeamUpdated: Oct 30, 20262 min read

Pipework crossing building expansion gaps and running between separate structures is exposed to large movements in every direction from ground settlement, thermal expansion and earthquakes. When rigid connections cannot follow these movements, pipes can rupture and critical systems such as fire protection and heating can fail. A U-Flex flexible connector is a movement-absorbing element whose U-shaped flexible loop relieves stress in rigid piping systems.

This article covers the construction, specifications, applications and installation points of U-Flex connectors.

What Is a U-Flex Connector?

A U-Flex (Omega U-Flex) connector is a flexible pipe connection in which stainless steel flexible elements are joined to form a U-shaped loop. Its name comes from this U form and its flexible construction. The loop geometry allows the two connected pipe ends to move relative to each other in any direction, absorbing movement in the X, Y and Z directions during earthquakes and settlement.

The flexible elements are stainless steel bellows-type sections in contact with the fluid, providing both tightness and mechanical strength.

Technical Specifications

Property	Value
Material	Stainless steel AISI 304 / AISI 316L
End connections	Flanged, weld ends, grooved
Braid material	Stainless steel AISI 304
Connection material	Carbon steel St37.2 (other materials on request)
Nominal size	Manufacturer range DN15 – DN300; DN25 – DN200 models are listed on orfa.com.tr
Pressure rating	Standard 175 psi and 250 psi (approx. 12 and 17 bar)
Temperature range	-80 °C … +600 °C
Certification	FM approved (Ayvaz Omega U-Flex)

Benefits

Movement in all directions: one unit absorbs X, Y and Z movement.
Protects rigid piping: reduces stresses in the pipeline and at connections.
Accommodates thermal expansion: takes up length changes from temperature variation.
Installation tolerance: the flexible design tolerates small misalignments and simplifies fitting.
Corrosion resistance: stainless steel ensures long life in humid and aggressive environments.

Applications

Building expansion gaps: pipe crossings between separate structures.
Fire protection systems: keeping fire lines intact during earthquakes.
HVAC systems: heating, cooling and ventilation lines.
Steam and hot water lines: where thermal expansion is significant.
Chemical and petrochemical plants: thanks to corrosion-resistant construction.

Tip: Support the bottom (return section) of the loop properly during installation and never subject the connector to torsion. For fire protection systems, always check the approvals required by the project specification (e.g. FM).

Frequently Asked Questions

What movements does a U-Flex connector absorb?

Thanks to its U-shaped loop, it absorbs movement in the X, Y and Z directions, including building settlement, thermal expansion and seismic displacement.

How does U-Flex differ from an axial expansion joint?

An axial expansion joint only absorbs movement along the pipe axis and transfers pressure thrust to the anchors. A U-Flex connector absorbs movement in all directions thanks to its loop geometry, making it suitable for expansion gap and seismic crossings.

Which sizes are available?

The manufacturer range is DN15 to DN300 (DN25 – DN200 models are listed on orfa.com.tr), with standard pressure classes of 175 psi and 250 psi and flanged, weld-end or grooved connections.

Conclusion

U-Flex connectors are a practical, reliable way to protect pipework against movement in every direction at expansion gap and seismic crossings. Selected with the right size, pressure rating and connection, they extend the life of the installation. For other expansion solutions, see our Metal Bellows Expansion Joints page.

Online Store