SAPPMA
Plastic pipe specifications, design and performance The durability of plastic pipe is legendary; the material is used in over 50% of the water and sewage networks installed globally. Optimal performance depends on various factors, especially the strict adherence to product, design and construction standards. A good understanding of pipe/soil interaction adds further benefits. By Alastair Currie
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ithin the world of Southern African Plastic Pipe Manufacturers thermoplastic pipe, Association (SAPPMA). there are a range of Venter recently hosted a SAPPMA webinar material options that on the subject (Webinar VII), presented can be used to form them, depending on by design and construction management the downstream application requirements. experts. (Visit www.sappma.co.za to Within the spectrum, polyvinylchloride (PVC) download the training material for quick and high-density polyethylene (HDPE) are the reference and guidance.) best known. Understanding their material In addition to ensuring quality standards characteristics is important from among its members, technical design, specification and training and industry installation perspectives. consultation are core Construction is a “Aspects like stress SAPPMA mandates. This and strain, as well was the motivation multidisciplinary as how the pipe is for the launch of field, where sharing supported above and the Installation and technical knowledge in the ground, will Fabrication Plastics is vital in achieving have a direct bearing Pipe Association on its performance (IFPA) – a SAPPMA the UN’s Sustainable characteristics. Each initiative aimed at Development Goals site has its own unique ensuring best practice in conditions, like the the sector. depth of excavation, marshy Pipe manufacturers belonging conditions, traffic loads or higher-thanto SAPPMA subject their products to normal groundwater levels, which must be extensive testing, supported by ongoing factored in during the design and pipelaying investment in research and development. The stage,” says Ian Venter, technical manager, same holds true for polymer manufacturers.
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SAPPMA’s quality assurance programmes, which include unannounced audits at member production facilities, ensure that specifiers can buy with confidence, knowing that key specifications, like wall thickness, and critical dimensions are consistently adhered to. “The reality is that any type of material system will fail if it’s not properly designed, manufactured, and installed, so it’s vital to take a holistic approach,” Venter explains. “Where pipe failures do occur, the root causes are often not difficult to find. It’s just a matter of ensuring that products are well understood and that the design and application have been aligned to their unique properties, characteristics, as well as jointing capability. By doing this, it is quite easy to further prevent failures of this type,” he continues.
Tougher and more flexible Research and development advances have been significant over the years, with the industry progressively shifting from rigid to flexible plastic pipes. Tensile strengths have also vastly increased for all plastic pipe materials, such as polyethylene (PE) pipes (12 MPa to 24 MPa) and PVC (45 MPa to 75 MPa), allowing them to enjoy market shares typically occupied by steel and concrete pipe. One advantage of modern-day plastic pipes is that they offer the designer internal pressure and loadbearing capabilities, while remaining flexible to soil movements
