Drainage pipes are used to collect and remove rainwater and infiltration water from the soil. They operate by gravity and perform a structural function in protecting civil works, preventing water stagnation and soil overload. In these applications, mechanical strength and geometric stability matter more than pressure resistance, making pipe design and the extrusion process a decisive factor for system performance.
The drainage solutions available on the market differ in geometry, wall structure and material, depending on the required mechanical performance and installation conditions. In this context, the pipe's configuration serves not only to convey fluid, but directly contributes to the system's resistance to soil and overhead traffic loads. The relevant standards define strict parameters in terms of ring stiffness, deformation resistance and durability, making precise control of the pipe's dimensions and structure essential already at the extrusion stage – one of the key dimensional requirements for this type of product.
The choice of pipe type therefore depends on the application context, installation depth and the stresses expected over time.
- perforated corrugated pipes in PE or PP
- double-wall pipes with a smooth interior
- drainage pipes with filter coating
The EN 13476 standard defines nominal diameters typically ranging between DN 100 and DN 1000, as well as ring stiffness classes (SN) and requirements for resistance to deformation over time.
Dimensional requirements and process challenges
Non-uniform dimensional control can result in local variations in ring stiffness, directly affecting the pipe's ability to maintain the performance required by the standard throughout the structure's service life. In the extrusion of drainage pipes, the main challenges concern:
- uniformity of the corrugated profile
- wall thickness control, achieved through precise adjustment of extrusion flow rate, haul-off speed and calibration system, to ensure a constant thickness along the entire length of the pipe
- ring stiffness stability, ensured by uniform cooling and accurate synchronization between process stages, to avoid local variations in thickness or geometry
- synchronization between extrusion and corrugation
Even minimal variations in the profile can compromise compliance with the required SN class, making precise control of flow rate and cooling essential.
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