GLASS-REINFORCED PLASTIC PIPES
Glass Reinforced Pipes (GRP) have been used to replace metal pipes in potentially corrosive environments. The pipe is a composite, and is difficult to assess its condition. It normally fails catastrophically from mechanical loading.
Structure of GRP Pipes
Hobas GRP pipelines constructed out of centrifugally-cast pipe, and joined using symmetrical elastomeric joints.
Glass fibre is the major reinforcing material used to achieve the high mechanical performance in the axial and circumferential direction. It is a key constituent of most layers of the GRP pipe wall. Another key constituent is the unsaturated polyester resin and it is generally mixed with various filling materials of natural or artificial origin – typically calcium carbonate CaCO3 powders, such as limestone, marble or dolomite – in order to achieve certain mechanical properties (stiffness).
The sealing material selected to fill the gap between the pipe and joint is EPDM (ethylene propylene diene polymer). It is water-resistant, exhibits good chemical resistance, and has an excellent ability to restore its shape after being stressed and relieved.