Expansion Joints

Marine Rubber Expansion Joint: Vibration and Noise Control on Ships

Discover how marine-type rubber expansion joints reduce vibration and noise at pump, engine and compressor connections on ships and in shipyards, and review their specifications.

ORFA Technical TeamUpdated: Oct 30, 20263 min read

Marine-type vibration-absorbing rubber expansion joint with rotating flanges

On board ships, pumps, main and auxiliary engines and compressors generate continuous vibration. Once transmitted into the pipework, this vibration loosens connections, causes fatigue cracks and equipment failures, and creates noise that affects crew comfort. A marine rubber expansion joint is a flexible synthetic-rubber connector that reduces the transmission of this vibration and noise into the piping system.

This article covers what marine-type rubber expansion joints do, their benefits, specifications and correct use.

What Is a Marine Rubber Expansion Joint?

A marine-type rubber expansion joint is a flexible pipe connector made of special synthetic rubber and installed on the suction and discharge lines of pumps, engines and other machinery in ship systems. Its flexible body:

reduces the transmission of machinery vibration and noise into the pipework,
absorbs elongation and contraction caused by temperature changes,
accommodates axial, lateral and angular movement (three-dimensional movement), compensating irregular movement in circuits such as cooling lines.

Benefits

Vibration and noise isolation: the soft, flexible body dampens vibration in all directions and limits structure-borne noise.
Heat resistance: the heat-resistant rubber allows use in hot water circuits.
Lower stresses: absorbs thermal elongation and contraction and compensates lateral and angular movement.
Damps pressure pulsations: helps reduce the effect of pressure surges and knocking on the pipework.
Easy installation: rotating flanges make bolt-hole alignment simple.
Flexible flange options: can be fitted with flanges to suit the pressure class of the line.
Low maintenance: no packing is needed; the rubber flange faces provide the seal.
Vacuum service: a reinforcing ring in the body allows use on lines where vacuum may occur.

Tip: A rubber expansion joint softens the effect of water hammer but does not remove its cause. Fast-closing valves and pump trips should be addressed separately.

Technical Specifications

Property	Value
Body material	Special synthetic rubber
Connection	Rotating flanges
Nominal size	DN25 (1″) – DN300 (12″)
Pressure	Up to 16 bar max.; operating pressure depends on size and temperature

Applications

Suction and discharge lines of marine pumps
Main and auxiliary engine connections
Compressors and other rotating machinery
Cooling water circuits
Shipyards and shipbuilding projects

Selection and Installation Notes

Install the joint as close as possible to the vibration source (pump or engine).
Check fluid, temperature and pressure against the limits of the rubber material.
Do not force the joint to correct pipe misalignment.
If the pipe anchoring cannot carry the pressure thrust, consider suitable control rods.

Frequently Asked Questions

What movements does a marine rubber expansion joint absorb?

It accommodates axial, lateral and angular movement and reduces the transmission of machinery vibration and noise into the pipework.

Which sizes and pressures are available?

Sizes from DN25 (1″) to DN300 (12″), up to a maximum of 16 bar. The allowable operating pressure may be lower depending on size and temperature.

Can it be used on lines under vacuum?

Yes. A reinforcing ring in the body allows use on lines where vacuum may occur.

Conclusion

Marine rubber expansion joints are a practical, effective solution for vibration and noise control on ships and in shipyards. Used in the right size, pressure rating and position, they extend the life of the pipework and connected equipment and improve comfort on board. See more models on our Rubber Expansion Joints page.

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