The resistance of grp to corrosion by water and most chemical combined with high mechanical strength make filament wound pipes an ideal solution for fluid handling, both above and below ground.
The main markets for filament wound pipes are in
• surface drainage, waste water and sewage treatment, both urban and industrial
• water cooling systems
• industrial processes
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 gel stage. The detail construction and thickness of the barrier layer depends on the nature of fluid flowing through the pipe and pipeline operating conditions (free flow, turbulent suspensions content, and so on).
Then the filament wound structural layers are applied. Fibreglass rovings impregnated by passing through 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 pipes 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
Smooth bore – reduced pumping costs
Low maintenance costs
¼ 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
Pipe diameters and lengths available
|Internal Diameter mm||Length m|
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
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 rating.
The fitting are made from sections of pipe cut and laminated together. Bends of different radii and swept angle, reducers, Tee’s, Y’s can all be manufactured to suit customer’s requirements. The joint detail of the fittings matches those of the pipe.
BSEN 1796 Plastics piping systems for water supply with or without pressure. Glass-reinforced thermosetting plastics (GRP) based on unsaturated polyester resin (UP)
BSEN 14364 Plastics piping systems for drainage and sewerage with or without pressure. Glass-reinforced thermosetting plastics (GRP) based on unsaturated polyester resin (UP). Specifications for pipes, fittings and joints
BS ISO 25780 Plastics piping systems for pressure and non-pressure water supply, irrigation, drainage or sewerage. Glass-reinforced thermosetting plastics (GRP) systems based on unsaturated polyester (UP) resin. Pipes with flexible joints intended to be installed using jacking techniques
BS 7159 Code of practice for design and construction of glass-reinforced plastics (GRP) piping systems for individual plants or sites
American Water Works Association (AWWA) C950-95 Fiberglass pressure pipe
The quality control is to an ISO9000 registered quality control scheme using BS, EN and ASTM test methods.
The production site is also registered to ISO14000 Environmental System Management.
|Coefficient of thermal conductivity||W/mk||0.25|
|Coefficient of thermal expansion||mm/mmoC||2.0 x 10-5|
|Tensile strength – axial||N/mm2||200-300|
|Tensile strength – circumferential||N/mm2||30-80|
|Flexural strength – axial||N/mm2||60-200|
|Flexural strength – tangential||N/mm2||400-600|
|Flexural modulus – axial||N/mm2||7000-7500|
|Flexural modulus – tangential||N/mm2||8000-8200|
|Glass fibre content||% wt||65-73|
|Tensile modulus – axial||N/mm2||11,000-13,000|
|Tensile modulus -circumferential||N/mm2||22,000|
|Poisson ratio – axial||0.4|
|Poisson ratio- circumferential||0.5|