
What is a rubber expansion joint?
A rubber expansion joint is a flexible pipeline element with an elastic bellows made of EPDM or NBR. The bellows is nylon-reinforced and absorbs axial, lateral and angular movements. The flanges connect the expansion joint to the existing pipework. This component is also called a rubber compensator, flexible connector or Gummikompensator. Unlike a metal expansion joint, a rubber expansion joint also dampens vibration and structure-borne noise. That makes it the first choice for pump stations, HVAC systems and drinking water supply.
EPDM expansion joint – for water, air and drinking water
An EPDM expansion joint suits water, air, dilute acids and alkalis. EPDM is the standard bellows material for drinking water applications. The temperature range is −30 °C to +110 °C. EPDM resists ozone, ageing and UV exposure. A drinking water expansion joint with EPDM bellows meets the requirements for elastomers in contact with drinking water. Fergo stocks EPDM expansion joints from DN15 to DN500 with flange PN10/16 or threaded connection (BSPP). Lengths: 130 mm (OG130) and 150 mm (OG150). For threaded connections the twin-arch OG111 series with 200 mm length is available.
NBR expansion joint – for oil, fuel and biogas
An NBR expansion joint is the right choice for mineral oils, fuels, hydraulic fluids and biogas. NBR (nitrile) resists hydrocarbons and oil-bearing media. The temperature range is −30 °C to +90 °C. NBR expansion joints are typically used in oil and gas installations, biogas plants and fuel lines. Fergo stocks NBR expansion joints from DN25 to DN500 with galvanised steel flanges PN10/16. Length: 130 mm (OG130). The NBR version has a black bellows — the EPDM bellows is red.
EPDM vs. NBR expansion joint – which bellows for your medium?
| Feature | EPDM bellows | NBR bellows |
|---|---|---|
| Typical media | water, drinking water, air, dilute acids | mineral oil, fuel, hydraulic oil, biogas |
| Temperature | −30 °C to +110 °C | −30 °C to +90 °C |
| Drinking water | yes | no |
| Oil resistance | no | yes |
| Ozone/UV resistance | yes | limited |
| Bellows colour | red | black |
For drinking water applications choose the EPDM expansion joint. For oil and fuel lines choose the NBR expansion joint. Check media compatibility with our resistance check tool.
Technical data – DN, PN, flange and length
All Fergo rubber expansion joints follow a uniform construction. Key data:
- Nominal size: DN15 to DN500 (flanged), DN15 to DN50 (threaded)
- Connection: flange PN10/16 to DIN EN 1092-1 or female thread (BSPP)
- Flange material: galvanised steel (standard), stainless steel (special), galvanised ductile iron (threaded)
- Bellows: EPDM or NBR, nylon-reinforced
- Length: 70 mm, 130 mm, 150 mm, 200 mm (depending on series)
- Operating pressure: 16 bar (PN16)
- Temperature: −30 °C to +110 °C (EPDM), −30 °C to +90 °C (NBR)
- Design: single-arch (OG130, OG150) or twin-arch (OG111)
- Option: vacuum ring for vacuum applications
- Conformity:EU Pressure Equipment Directive 2014/68/EU
For aggressive media Fergo offers special versions with PTFE or Hypalon coating and stainless steel flanges on request.
Applications – heating, drinking water, industry and chemicals
A rubber expansion joint is found in virtually every building services and industrial plant. In heating and cooling systems the compensator absorbs thermal length changes ahead of and behind boilers, pumps and heat exchangers. In drinking water supply a drinking water expansion joint with EPDM bellows provides a low-vibration connection between booster pump and distribution network. In biogas and wastewater plants an NBR expansion joint protects the line from vibration caused by gas compressors and agitators. In the chemical industry special versions with PTFE-coated bellows and stainless steel flanges suit aggressive media. In shipbuilding and offshore installations rubber expansion joints compensate the constant movement of the vessel structure.
Rubber expansion joint in stock – EU-wide delivery
Fergo stocks all 164 rubber expansion joint variants for immediate dispatch. Standard shipping via DHL reaches customers across Europe within a few working days. Each expansion joint ships with datasheet and declaration of conformity. For larger projects or special configurations (PTFE, Hypalon, stainless steel) the Fergo team advises individually.










