The design philosophy of GRP pipes is to provide products with suitable properties and the required margin of safety that will enable the pipe to work satisfactory after an extended period of operation (50 years) under typical service conditions.
Using the continuous advancing mandrel process, which represents the state of the art in GRP pipe production, a very compressed laminate is created that maximizes the contribution from the three basic raw materials, namely glass-fiber, resin and sand.
The Continuous advancing mandrel equipment has the capability of applying a special inner resin liner for severely corrosive applications, while utilizing a standard type resin for the structural and outer portion of the laminate.
During the process, other materials such as a glass veil or a polyester veil can be used to enhance the abrasion, the chemical resistance and the finishing of the pipe.

Liner
It is in direct contact with the conveyed fluid and guarantees the maximum resistance to the chemical attack from the fluid itself. Moreover, the liner presents an internal surface particularly smooth, without defects, cracks or delaminated zones. The liner is composed of one resin impregnated glass veil and one glass mat tape and is produced in two steps (inner liner and outer liner)

Mechanical resistant layer
Its function is to render the pipe wall resistant to the stresses due to the design conditions (stresses due to the internal and/or external pressure, flexural strength due to the external loads etc.) and generated by transport and laying operations. The thickness of the filament depends then upon the design conditions. The mechanical layer is composed of resin impregnated continuous glass filament roving.

Gel coat or external layer
It has a thickness of about 0,2 mm and consists of pure resin without glass reinforcement. It guarantees the complete impregnation of the peripheral fibers, thus yielding the external pipe surface completely free of protruding fibers and well finished. The ultraviolet ray inhibitor is always added to the external coating, to prevent the nearly negligible weathering effects.

Diameter and classes
GRP pipes using Continuous Advancing Mandrel are manufactured in diameters ranging from 100 mm to 4000 mm. Any nominal diameter can be manufactured.
Nominal pressure classes are 4, 6, 10, 16, 20, 25, 32 bar
Intermediate or higher pressure classes are considered on request or depending on the design conditions
Pipes are also classified according to specific pipe stiffness. Specific pipe stiffness classes are 1250, 2500, 5000 and 10000 Pa.
Intermediate or higher specific pipe stiffness classes are available on request or depending on the design conditions.