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.


Manufactured Rubber Bellow

What is a Safetech Full Face Rubber Bellows?

Designed with a rubber flange and backing ring...

  • Materials
    Full range of rubber types, backing rings in stainless steel, carbon steel - hot dipped galvanised or coated.
  • Application
    Typically seawater, cooling water, drinking water.
  • Rating
    Engineered to meet your exact specification in any rubber, flange drilling and length.
  • Approvals
    WRAS (EPDM Rubbers)

How to select a large rubber bellows

1 Temperature & Pressure2 Rubber Compatibility3 Diameter and Length4 Flange Drilling & Restraints5 Movements6 Let us help
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.
Rubber bellows Rubber CompatibilityThe rubber compound used for the inner layer of the bellows must be compatible with the working fluid. Drinking water requires a WRAS approved EPDM, oils require Nitrile and so on - our Bellows Finder can help you with finding the right rubber.
Rubber bellows Diameter and LengthMoulded bellows are manufactured in set combinations of diameters and lengths. However, our handmade Safetech range can be manufactured in any diameter and length to suit your application, only the more standard sizes are shown on the Safetech range tab.
Rubber bellows Flange Drilling & Restraints Any flange drilling can be supplied; if you are uncertain about what you already have installed our Flange Finder will help you identify it. The HVAC and Elaflex ranges have swivel flanges; the Safetech range has full face rubber flanges. Our web shop stock is PN10/16. Bellows will exert a pressure force on the pipe (see FAQ) which must be restrained or absorbed at the piping anchors. All our flanged rubber expansion joints are available with tie rods and we can offer hinges or gimbals on the Elaflex and Safetech products.
Rubber bellows Movements Moulded rubber bellows have a defined movement range, which is shown for each type in the Range tab, movements listed are non-concurrent (see FAQ). A Safetech bellows will be designed to meet your required movements.
Rubber bellows Help Call our expert team on +44 (0) 1384 881188 or email us at or use Live Chat on this web site - we are here to help, please get in touch.

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

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.

Need a detailed quote?

Get A Quote. On us.

We will provide full technical details together with, pricing and shipping timescales. For more complex engineered quotes, preliminary sketches and calculations will be available.


Who can you talk to?

Try our sales and customer service team on 01384 881188

They don't bite. And they know what they're talking about. Call the team any time from 8:30am to 3:30pm weekdays, 12:30pm Fridays or use LIVE CHAT if you would prefer a quick text answer. For more complex queries, send us any pro-forma documentation using the get a quote form below or email us

Call Us

Not sure what flange spec you need?

Use the FlexEJ Flange Finder to find out

FlexEJ stock a full range of specs and types for our bellows. Or call our expert team on +44 (0) 1384 881188.

Frequently Asked Questions

Q. How do you identify flanges?
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.
Q. Do you design your own metal expansion joints or rubber bellows?
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.
Q. Can you match another brand / manufacturer of expansion joint or bellows?
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.
Q. What do I need to know to identify an existing expansion joint or bellows?
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.
Q. Do you have rubber bellows for drinking / potable water or with WRAS approval?
A. Yes, our Elaflex ERV-R and ERP rubber bellows have WRAS, DVGW and ACS approval for drinking water. 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.

Can't quite find the right bellow?

Try the FlexEJ Bellows Finder

Or call our expert team on +44 (0) 1384 881188

Got a quick question?

Use Live Chat. Or call us.

For instant advice use the Live Chat link to message one of the sales team. Or call them direct on +44 (0) 1384 881188

Get A Quote

Please complete the short form here and we'll get back to you within 24hrs Monday to Friday (quicker if marked urgent).

Alternatively, you can also call our expert team directly on +44 (0) 1384 881 118 from 8:30AM to 4:30PM weekdays (12:30PM Fridays), who will be only too pleased to talk through your requirements and technical queries over the phone.

Visitors are also welcome Monday to Friday although please get in touch beforehand to let us know you're coming.

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    Industry experience

    FLEXEJ Ltd was formed in 2002 by two professional engineers who brought together an already highly respected design capability with business and commercial skills gained in large multinational companies.
    • Our focus has always been on application and design – helping our customers find the best value solution.
    • We have a strong engineering and manufacturing team with experience in petrochemicals, refining, nuclear, desalination though to HVAC.
    • The team is also very familiar with meeting complex requirements for documentation, in process NDT and test on projects. We have supplied many large end-users such as EDF, Exxon, Shell, Reliance & QatarGas working with major contractors such as JGC, Foster Wheeler & Technip.
    FlexEJ Industry Experience