Comment: Pipe research will help industry look again at plastics
A new campaign with associated research aims to dispel common myths in the industry around the performance and durability of plastic pipes
by Caroline Ayres, Director, British Plastics Federation Pipes Group
The September launch of a campaign initiative by the European Plastic Pipe and Fittings Association, TEPPFA, is set to raise awareness of the use of plastic pipes in the UK water and wastewater industry.
Discover: Plastics is no lightweight campaign; it has a solid body of research evidence behind it, taken from sites across Europe including the UK, and showing like-for-like comparisons between plastic pipes and those of other materials. The research has covered a wide range of issues relating to the performance of commonly used below ground pipes: deformation and flexibility under loading and ground conditions, corrosion resistance, speed of installation, strength and longevity in use.
The research on deformation and flexibility, for example, unquestionably underpins everything the plastic pipes industry has been saying and doing for some time on best practice plastic pipe installation for below-ground sewer applications. It proves once and for all that weight does not equate to strength (more on that later).
The evidence in favour of plastic pipes really stacks up. Despite having been ignored by competitive material manufacturers for years, now there is no getting away from it: plastic pipes are reliable in use, perform well with fewer defects per kilometre than other directly comparable materials, and are rightfully becoming increasingly popular with installers in the UK and elsewhere. They are also being used at much larger diameters than ever before, and in SuDS and contaminated land applications have proven the material of choice due to their appropriate performance characteristics.
Application studies are included on the new Discover: Plastics micro-site, and these are being added to as member companies successfully complete projects around the UK and in the other countries taking part in the campaign – France, Germany and Poland.
The pipes industry has matured considerably in the last few years, with recognition of the importance of good training having a direct impact on the long-term quality of below-ground pipes and fittings. Many companies involved in installation work have invested heavily in courses. The Drain Repair courses at the WRc, for example, are still very successfully running after more than a decade and have trained hundreds of installers, supervisors and decision makers in best practice inspection, cleaning, repair and replacement.
The necessary and increased focus on protecting the pipe network as a whole – from correct first-time installation, to improving training, to the careful maintenance of both old and new pipes – means it has become increasingly recognisable to everyone closely involved in the industry that taking a more holistic view pays. Using the most appropriate materials and components for the job means sewerage operations benefit from improved reliability, leading to reduced maintenance time for engineers, less material wastage and enhanced whole asset life. This isn’t a new concept as the methodical approach to pipe materials selection was first mooted in the industry manuals of the 1980s and 1990s. It is therefore good news all round that the wider range of diameters being used in plastic for potable and non-potable applications reflects the more pragmatic approach being taken by specifiers and engineers.
One of the studies cited, the four-year Buried Pipes Study, showed that flexibility is a benefit when it comes to traffic loading, as if a pipe is more rigid than the soil surrounding it, it has to resist all the loading from above, whether heavy goods vehicles, buses or aircraft. Correctly installed plastic pipes actually spread the load to the ground itself, meaning they are subject to lower loads than traffic and weight of soil exert. Once the backfill and soil have settled after installation, traffic loads have no further impact on deflection. So, correct installation and good workmanship ensures pipe deflection remains within the tight limits we have set for the UK: 5% for highway applications and 6% for adoptable sewers.
Flexible pipes are also more tolerant of defects, as proven in the extensive SMP Study, which showed that defects occurred on average 41 times per km for rigid pipes and just 6 times per km for plastic pipes.
To conclude, there is no escaping sound research to back up claims and this new campaign has plenty of solid research at its heart. The next few months could be interesting for the industry.
For info: www.discover-plasticpipes.com/UK
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