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Design & Manufacturing
Full in-house design & manufacture to EN / ASME / PED.

ISO14001 Accreditation
FlexEJ has an accredited Environmental Management System.

Large-scale Rubber Expansion Joint Design & Manufacturing

Safetech is FlexEJ’s sister company located in Spain. Safetech designs and manufactures rubber expansion joints in their own dedicated facility near Bilbao. This ability to hand build rubber expansion joints means we can offer lengths, diameters, movements, materials, restraints and rating to meet your precise requirements. 

Pressure balanced rubber expansion joints and PTFE lined rubber expansion joints are just two of the specialty products we design and manufacture.

How to Select a Large Rubber Bellows

Rubber bellows Temperature & Pressure Temperature is the most critical as it directly influences the choice of rubber – but also the actual pressure capability of the bellows. The stated maximum rated pressure is maintained up to around 50ºC for most rubber bellows, for higher temperatures check the data in the Range tab.

Safetech Rubber Bellow Expansion Joints:

Safetech typically offers 1, 2, 3 or 4 convolutions in each diameter of expansion joint. All manufactured rubber bellows are available with a huge range of flange, material and restraint options:

Multiple arch engineered bellows

DN100 to DN3600+
Multiple arch engineered rubber bellows


Single, double, triple or quad arch

Each additional arch in the bellows provides additional movement capability. This allows very large axial, lateral or angular movements to be delivered by a single, compact expansion joint.

The length of the expansion joint can be adjusted to suit your piping layout or existing equipment meaning the full movement capacity of the bellows is available to you in all cases.

Pressure Balanced engineered bellows

DN100 to DN3000+
Pressure Balanced engineered rubber bellows


Eliminates Pressure Force

A pressure balanced rubber expansion joint uses two rubber bellows to provide the movement specified and a third, larger diameter rubber bellows to generate an equal pressure force. The larger diameter “balance” bellows is cross connected to the inlet and outlet flanges so it cancels out the pressure force of the smaller bellows. Net result no pressure force acting on your pipe, flanges or equipment.

Safetech can design and manufacture exactly what you need for your specific application so don’t be constrained by catalogue dimensions or performance. We can offer reducing bellows to connect between different pipe sizes, extended lengths to eliminate additional pipe, simple spool type ends for banding, non circular…

Restraint Hardware

Tie Rods, Lugs, Hinges, Collars
Engineered rubber bellows restraint hardware



Safetech’s preferred design is to manufacture the flange backing ring in segments with integral tie rod lugs. This approach makes assembly more straight forward as each segment is lighter to handle. Having the tie rod lug integral with the backing flange reduces bending stresses and eliminates bolt on lugs altogether, again an installation advantage. Safetech can also supply one piece flanges if requested. If the joint is to be used to allow easy dismantling of line equipment we can also provide a dismantling collar on the bellows which allows the tie rods to compress the convolutions(s) to ease removal.

Linings and Liners

PTFE, Stainless Steel
Engineered rubber bellow linings and liners



Safetech can provide a PTFE lining in any of its rubber bellows, the PTFE affording greater chemical resistance than the rubber. We also provide a variety of Stainless Steel “Top Hat” liners which keep the flow away from the rubber convolutions – flow straightening vanes are an option. A metal liner is a good addition for any dirty media with solid content or elevated temperatures.

Can't see what you want? Need help?
Call us. Or use Live Chat.

For instant advice. We can custom-design and engineer almost any expansion joint you need for delivery in the UK or worldwide. Call our expert team on +44 (0) 1384 881188 Or email us sales@flexej.co.uk

Frequently Asked Questions

A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

A. Yes, FlexEJ has full design capability for engineered metal expansion joints and can work to any recognised standard – typically EJMA, B31.3/Appendix X, EN14917 plus PED and/or other customer specifications. Engineered rubber expansion joints are typically designed to meet the FSA guidelines plus PED and/or other customer specifications For technical assistance please contact us or use the Live Help link on this page.

A. Yes, if you have the details we can normally offer an equivalent, our FAQ here gives the information we will need for a full selection. For technical assistance please contact us or use the Live Chat link on this page.

A. To identify an existing expansion joint we need to know: nominal bore, overall length and flange type plus service, temperature, pressure and required movement if known. Try our Flange Finder to help identify the flange and you can send us a picture of the existing part using the Contact us form. For technical assistance please contact us or use the LIVE CHAT link on this page.

A. Yes, our Elaflex ERV-R and ERP rubber bellows have WRAS, DVGW and ACS approval for drinking water, see our Elaflex pages for more information. The Safetech manufactured to order rubber bellows can be supplied with WRAS approved EPDM linings. Our MRCA copper ended metal expansion joints also have WRAS approval. For technical assistance please contact us or use the LIVE CHAT link on this page.

Please visit our full FAQ page to see all our frequently asked questions.