Tests on Plastic Pipes

Pipework systems made of thermoplastic or glassfiber-reinforced plastics are used to transport liquids (mostly water) and gases and as such are subject to stringent quality requirements.
Thermoplastic pipes, made for example of PE, PP, PVC or PEX, are produced in various forms. They are distinguished by their mechanical properties, including corrosion resistance, resistance to chemicals, low weight, flexibility, adequate ring stiffness and low surface roughness.
Pipes with smooth internal and external surfaces are frequently used as header pipes for waste water disposal. They can be produced with solid walls or as foam-core pipes. Outside diameters range from 16 mm to 1200 mm. For internal pipework heat-resistant pipes are used; these must also satisfy stricter fire safety requirements.
The range of application of corrugated pipes ranges from cable protection in mechanical engineering, shipbuilding and the automotive industry to drainage, seepage, waste water and sewer pipe applications, with diameters up to 1800 mm. Due to the corrugations these pipes are very flexible in the longitudinal direction and can easily adjust to their environment while retaining a high degree of ring stiffness. Specific mechanical properties can be achieved by the way in which the pipe wall is profiled or by means of hollow walls.
Different materials can be combined to achieve specific properties. A typical example of a multi-layered composite pipe consists of an aluminum pipe surrounded inside and outside by an adhesive layer with cross-linked PE (PEX). Such pipes are highly flexible, easy to lay and impervious to oxygen.
GFRP pipes usually possess greater ring stiffness and can also be used for transporting chemicals. These pipes are produced with outside diameters up to 3000 mm.

Quality standards in plastic pipe testing

Tests on pipes relate to the defined area of use. National building and construction authorities require pipes to be approved in line with specified criteria which are set out in great detail in specification standards or technical requirements. Requirements may vary considerably from country to country. Due to the wide range of application areas and differing materials, numerous national and international standards are used in the testing of plastic pipes. Both the material properties of the plastic and the performance characteristics of the finished pipe are tested, in many cases by ZwickRoell testing machines with their combination of precision and accuracy. The list below gives an idea of the range of tests applicable to underground PE pipework systems used for non-pressure drainage and irrigation applications in accordance with EN 13476-1. Dimensional measurements are not shown here.

Standard	Contents
EN 13476-1	Plastic piping systems for non-pressure underground drainage and sewerage. Structured-wall piping systems of unplasticized poly (vinyl chloride) (PVC-U), polypropylene (PP) and polyethylene (PE) - Part 1: General requirements and performance characteristics
	Material properties
ISO 1167-1	Resistance to internal pressure, 165 h
ISO 1167-1	Resistance to internal pressure, 1000 h
ISO 1133-1	Melt mass flow rate, MFR @ 190°C, 5 kg
ISO 728	Melt mass flow rate, MFR @ 190°C, 5 kg
ISO 1183	Determination of oxidation induction time, OIT
	Physical properties
ISO 2505	Determination of longitudinal reversion heating effects, PE fittings
ISO 12091	Oven test
	Mechanical properties of pipes
ISO 9969	Ring stiffness
EN 744	Resistance to external blows by the round-the-clock method, drop-weight method
ISO 13968	Ring flexibility
ISO 9967	Creep ratio
EN 1979	Tensile strength of a seam
EN 1411	Resistance to external blows by the staircase method, drop-weight method
	Mechanical properties of fittings
ISO 13967	Stiffness
EN 12061	Test method for impact resistance
EN 12256	Strength or flexibility of fabricated fittings
	Behaviour requirements
EN 1277	Tightness of elastomeric sealing ring joints
ISO 13260	Resistance to combined temperature cycling and external loading
EN 1055	Resistance to elevated temperature cycling
EN 1989	Resistance to elevated temperature cycling
EN 1989	Resistance to elevated temperature cycling
EN 1053	Watertightness