Captrad has a wide range of GRP Pipes and associated fittings

The main market for GRP Pipes, (fibreglass reinforced polyester) is in the public and industry, as follows:

  • Sewerage systems and sewage treatment (urban and industrial)
  • Distribution of drinking water (public and industrial)
  • Supply cooling water systems
  • Industrial processes
  • Transport and desalinated seawater
  • Transporting petroleum products
  • Gas transportation pipes
  • Transportation of various chemical solutions with temperatures up to 100 C.
GRP Pipes

GRP Pipes are Corrosion resistant and chemical mechanical (especially acids), making Captrads GRP pipes an ideal solution for wastewater disposal systems and drainage and other fluids difficult. This is combined with high mechanical resistance created by reinforcing glass fibre polyester resin.

High corrosion resistance combined with quick and easy installation (underground, surface, even underwater), makes Captrads GRP Pipes an excellent choice for most areas of use.

GRP filament wound pipe can be supplied in diameters from 250mm to 1200m in lengths up to 12m. The pipes can be supplied with plain or built-up ends to take a range of proprietary joint systems. All the pipe sizes can be supplied to BS, EN, and ASTM standards for pressure rating and pipe stiffness and in orthophthalic, isophthalic polyester, or vinyl ester resin depending on the chemical or corrosive service conditions.

The pipe manufacturing process is in two stages, both fully computer-controlled. First, an inner layer of the pipe (chemical barrier) with thicknesses of between 0.3 and 5.0 mm is laid onto the rotating mandrel and cured to the gel stage. The detailed construction and thickness of the barrier layer depend on the nature of fluid flowing through the pipe and pipeline operating conditions (free flow, turbulent suspension content, and so on).

Then the filament wound structural layers are applied. Fibreglass rovings impregnated by passing through a resin bath are wound at a controlled helical angle onto the rotating mandrel. The winding is bidirectional. Applying successive layers at the set angle continues until the designed thickness is achieved. The winding angles are chosen to provide suitable resistance to applied stresses in the two principal directions (axial and circumferential).

For pipes installed above ground, a special external layer is applied to ensure protection from UV, weathering, and external corrosive agents.

GRP filament would pipe offer a number of advantages over steel and concrete pipes including:

  • Corrosion-resistant Resistant to attack by most chemicals (with correctly selected resin)
  • Does not rust
  • No need for cathodic protection
  • Smoothbore reduced pumping costs
  • Low maintenance costs
  • Lightweight frac14; the weight of steel, 1/10 weight of concrete Can be made and handled in long lengths (up to 12m)
  • Reduced transport costs
  • Easy to install, less heavy lifting equipment required
  • Fewer joints - faster to install and fewer leakage issues at joints

GRP Pipe Sizes

GRP Pipe Sizes

Pipe pressure ratings and stiffness

Pipes can be made to one of several pressure ratings up to 32 bar. Internal pressure imposes both hoop and longitudinal force on the pipe wall so the filament winding pattern and wall thickness are adjusted to carry these forces.

Pipes can also be subject to negative pressure and, in buried pipes, from ground pressure.

The BS EN standards give recommended pipe wall stiffness ratings for different service conditions.

All the pipe diameters listed above are available in any combination of pressure ratings PN1, 6, 10 & 16 with stiffness factors SN2500, 5,000 and 10,000.

Selected pipe diameters can be supplied in pressure ratings PN 20, 25 and 32

Joint systems

Pipes can be supplied either plain ended to take a proprietary joint such as Viking Johnson or with a double ring sleeve coupler, (Reka type joint)
Laminated flanged ends can be built into the pipes and fitted with either steel or GRP flange rings.

All these joints carry the same pressure rating as the pipe itself.


A comprehensive range of fittings can be supplied to match the pipes for both pressure and stiffness ratings.

The fitting is made from sections of pipe cut and laminated together. Bends of different radii and swept angles, reducers, Tee&rsquo's, and Y’s can all be manufactured to suit customers' requirements. The joint detail of the fittings matches those of the pipe.

Associated Products

Manufacturing, Stocking and Delivering GRP Products

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and see how our GPR products can help your business


What Our Customers Say

Here at Captrad we are very proud of the service we provide and stand by every GRP product we provide.

Don't believe us? here are some kind words from our clients.