Flexible and Metal Hoses

V-Flex Loop: Flexible Protection Against Expansion and Seismic Movement

With its V-shaped flexible loop design, a V-Flex connector protects pipework against movement in every direction at building expansion joints and in seismic zones.

ORFA Technical TeamUpdated: Oct 30, 20263 min read

V-Flex flexible loop expansion joint (Omega V-Flex)

Pipework is subjected to movement in different directions due to expansion joints between building blocks, ground settlement, earthquakes and temperature changes. If these movements are not accommodated, stress builds up in pipes, joints and connected equipment, and leaks or fractures can occur. A V-Flex loop is an expansion element made of flexible metal hose legs arranged in a V-shaped loop that absorbs these movements in three axes.

This article explains the construction, working principle, applications and technical data of V-Flex connectors.

What Is a V-Flex Loop?

A V-Flex is a flexible loop formed by joining two flexible hose legs, each consisting of a corrugated stainless steel inner hose and a stainless steel braid, with a return fitting in a V shape. It is installed in the pipeline with flanged, weld-end or grooved connections. In the product range it is also listed as the Omega V-Flex expansion joint.

Working Principle

A single straight flexible hose is suitable only for lateral movement; axial extension or compression and torsion damage it. In a V-shaped loop, however, movement from any direction is converted into bending of the hose legs. This allows the element to absorb:

Axial movement: Extension or contraction of the pipeline along its own axis (thermal expansion).
Lateral movement: Horizontal displacement perpendicular to the pipe axis.
Vertical movement: Ground settlement or changes in level between building blocks.

While absorbing movement, the loop design also keeps the forces transmitted to the pipework and connected equipment low.

Tip: Do not subject V-Flex elements to torsion, install them in the orientation given in the manufacturer’s instructions and support them with hangers where necessary. Select a movement capacity greater than the total expected movement.

Benefits

Multi-directional movement: Absorbs axial, lateral and vertical movement with a single element.
Stress reduction: Reduces stresses in the pipework and equipment connections, extending system life.
Safety: Reduces the risk of pipe damage and leaks due to earthquakes and settlement.
Compact solution: Takes up less space than large expansion loops made of pipe.
Easy installation: Ready-made end connections allow fast fitting.
Fire protection compatibility: Ayvaz Omega V-Flex units are manufactured with FM certification; for fire protection use, confirm the approval scope (size, pressure class) against your project requirements.

Applications

Building expansion joint crossings
Seismic pipe connections in earthquake-prone regions
Fire protection systems (sprinkler and hose cabinet lines)
Fuel tanks and storage
Machine and equipment connections
HVAC systems
Power plants, chemical and petrochemical facilities

Technical Data

Property	Value
Corrugated hose material	Stainless steel AISI 304 / AISI 316L
Braid material	Stainless steel AISI 304
Connection types	Flanged, weld end, grooved
Connection material	Carbon steel St37.2 (other materials on request)
Pressure rating	Depending on model, e.g. 175 psi and 250 psi
Nominal size	Manufacturer range DN15 (1/2″) – DN300 (12″); DN25 – DN200 models are listed on orfa.com.tr
Operating temperature	-80 °C … +600 °C
Movement capacity	Standard ±40 mm (±1.5″) and ±100 mm (±4″); custom versions available

Frequently Asked Questions

What is the difference between a V-Flex and a straight flexible hose?

A straight flexible hose can only absorb lateral movement. The V-shaped loop of a V-Flex converts axial, lateral and vertical movement into bending of the hose legs, absorbing movement in three axes.

Where is a V-Flex used?

Most commonly at building expansion joint crossings, in installations in seismic zones, on fire protection lines and for tank connections.

How is the movement capacity selected?

Calculate the total expected movement from thermal expansion, settlement and seismic activity, and choose a model with a greater movement capacity. Standard options are ±40 mm and ±100 mm.

Conclusion

V-Flex loops protect pipework against movement caused by expansion joints, settlement and earthquakes, improving system safety and service life. Choosing the right movement capacity and connection type is key to trouble-free operation. For expansion joint solutions, see our Metal Bellows Expansion Joints page.

Online Store