GRP Pipes, Flanges and Backing Rings

Glass fibre pipes, flanges and fittings in glass fibre reinforced vinylester - GRV - and glass fibre reinforced epoxy – GRE.

GRP FRP Pipe (by filament winding)

GRP FRP Pipes are widely used in various applications from drainage to sewerage and potable water. Typically available in a Vinylester or Epoxy resin, GRP FRP tubes are favoured for a number of reasons. Lightweight pipes make it easier (and cheaper!) to transport, handle and install. The pipes also have a high level of corrosion resistance from both the external environment and the internal flow. They also have a lower density, lower thermal expansion factor and a high strength to weight ratio.

Elemy can supply various types of composite pipes DN 25 – DN 400 mm with Vinylester or Epoxy matrix and various pressure ratings and jointing configurations. 

• All pipes are plain end.
• Pipes are supplied with an inner corrosion barrier 0.5mm – 2.5mm.
• Large diameters available on request.

GRP FRP Flanges

GRP FRP Flanges form a rim that protrudes from the end of a pipe. They have several holes that allow two pipe flanges to be bolted together, with a connection formed between the two pipes. A gasket may be fitted between two flanges to improve the seal.

Flanges available:

  • DN 25 – DN 2500 in GRV and GRE
  • Cylindrical or Conical Inner configuration
  • Pressure ratings 3, 6, 10, 16, 20, 25 and 32 bar


Stub Flanges by Resin Transfer Moulding offer an excellent competitive solution with very high and constant quality.

  • The dimensions comply with the specified standards for each particular diameter and pressure class.
  • Various internal diameters are available to match all types of pipe. Diameters are available from DN 25 mm to DN 2500 mm.
  • Pressure ratings from 3 up to 40 bar.
  • SMC Stub Flanges Standard resin is Vinylester Derakane 411 or equivalent.
  • RTM Stub Flanges Epoxy resin, Derakane 470 or other resin on request.

Resin Transfer Moulding is a resin injection process consisting of five phases. The RTM process consists of five phases; placement of reinforcement, mould closure, resin injection, resin curing, and finally; demoulding. The process is automated to a maximum extent and therefore has significant advantages over alternative production methods such as hand lay-up or spray-up. These advantages include:

  • Strong products with a high strength-to-weight ratio
  • Very accurate dimensions
  • Constant quality
  • Pre-defined glass content
  • Precise fibre orientation
  • A short manufacturing cycle
  • Low styrene emission
  • Machining is limited to trimming product ends or edges


High pressure flanges for large diameters also available.

Stub flange, fixed flange, blind flange and backing ring all available.

GRP FRP Backing Rings

GRP FRP Backing Rings by Resin Transfer Moulding and Hot Pressing offer an excellent competitive solution to stainless steel, with very high and constant quality.

Glass fibre Reinforced Vinylester (GRV) Backing Rings made by Resin Transfer Molding (RTM) and Compression moulding (CM/SMC) are corrosion free, high performance products, suitable for both Thermoplastic and Thermoset pipe systems. The RTM and CM/SMC manufacturing technology are closed mould manufacturing methods, ensuring high fibre content and high performance laminates, capable to handle high mechanical loads.

Composite Backing Rings are a very good and competitive alternative for Stainless Steel alloys (SS 304 / SS 316 / Duplex), are light weight compared to steel and easy to handle. The Backing Rings have a specific inner diameter to meet the dimensions of PE, PP, PVC and GRP stub flanges of the pipe system.

Specifications of Composite Backing Rings:

  • Resin: Bisphenol A based Vinylester
  • Glass reinforcement: E-glass
  • Core material (RTM Backing Ring): Vinylester bonded silica
  • Colour: Black, Grey or off-white
  • Maximum operational temp.: 80°C.
  • UV resistant
  • Max. Working Pressure in pipe system: as specified on product drawing
  • Max. Test Pressure in pipe system: as specified on product drawing

The allowable operating temperature can be increased to 110°C. if required (at cost).

The inside diameter of Backing Rings can be modified as per customers’ requirements.

All flanges available with drillings according to different Standards: EN 1092 / ASA / ANSI / JIS / AWWA / AS 4087

GRP FRP Access Covers and Frames

The unique combination of materials and production method guarantees excellent constant quality.

Contact Moulded Access Covers and RTM Access Covers in vinylester resin Derakane 411 or equivalent and in Derakane 470.

  • The dimensions comply with the specified safety standards for each particular pressure class
  • Diameters currently available in DN 500, DN 600 and DN 800 mm
  • With pressure ratings up to 6 bars