Plastics are not always seen as the most eco-friendly material, but, compare them closely with their rivals on a lifespan basis and you might be surprised.
Strong, durable, light-weight and flexible, PE is a sustainable material that will offer excellent, maintenance-free performance for generations. Energy efficient during its manufacture, PE also requires significantly less energy to transport and install than metal or concrete alternatives. And with its superior corrosion and abrasion resistance, PE also requires less pumping energy post installation, combining superb hydraulic characteristics with an excellent service life and leak-free performance.
Leak Free Solution
Around 3.37 billion litres of water are lost every day in the England and Wales supply system alone according to OFWAT’s latest figures.
The main cause of leaks is pipe failure, so reducing the number of pipe breakages will help prevent water from haemorrhaging from the system. The flexibility of PE offers the ideal answer: unaffected by ground movement and heave, PE pipes do not carry the same inherent risk of cracking as metal or concrete alternatives but are strong enough to withstand deformation from backfilling and traffic loading. What’s more, PE does not corrode; a common cause of leaks in metal pipes.
The UKWIR National Mains Failure Database contains details of around 500,000 water mains failures from over 95% of the UK companies for the period from 1995 to 2002. The comparison of failure records of cast iron, asbestos cement, PVC, ductile iron and PE clearly shows that PE has the lowest failure rate of all water distribution pipe materials.
That accolade is not only due to the strength and flexibility of PE, but also to the fact that PE pipes need fewer joints - and joints are the area where any pipeline is most vulnerable to leaks. PE pipes can be produced, transported and installed in longer lengths and GPS can provide coils of piping up to 200m long and straight lengths up to 18m long. This enables installation of pipelines with up to two or three times fewer joints than metal or concrete alternatives and, because lengths of PE pipe are fitted together with fully welded butt or electro-fusion jointing processes, PE pipes provide stronger, tighter, more leak-proof joints too.
Energy Saving - non-corrodible, light, durable and flexible
"From the view of the total life cycle, plastics can be considered as one of the most energy efficient materials." - GUA, The Contribution of Plastic Products to Resource Efficiency .
It is a well known fact that it takes less energy to produce PE pipes than it does to make steel, copper, ductile iron or aluminium pipes. All these metal products are very energy intensive. The significant energy consumption it takes to make them is often compounded by the need to galvanise steel and ductile iron pipes, requiring energy intensive zinc, and the need to apply energy intensive cement lining to ductile iron pipes for corrosion resistance.
Conversely, PE pipes save far more energy during their considerably longer lifespan than they use during production thanks to their lower transportation, handling, installation and maintenance energy requirements. For example, the density of steel is eight times greater than that of PE, enabling PE installations to avoid the use of heavy lifting equipment.
The case for PE’s lower energy profile is much more than anecdotal. Calculations compiled by GUA demonstrate that, when assessed on a life-cycle basis in comparison to traditional materials, plastic products on the market today have enabled energy savings of 600 to 1,400Mio GJ/a (1GJ = 0.024 tonne of oil equivalent) and provided greenhouse gas emission reductions of between 58 and 135mt per year – figures that put the savings somewhere between the entire C02 emissions of Portugal (60mt in 2000) and Belgium (120mt in 2000)!
The PE100+ Association asserts that when additional factors such as effects from emissions are taken into account on a lifecycle basis, PE pipe actually has ten times less environmental impact than equivalent ductile pipe and on average 1/3 of that of traditional materials. It refers to the critical evaluation of twelve European Environmental Lifecycle Analysis studies that concluded that from an environmental point of view plastic is more sustainable than traditional materials in the production of pipes. Read the full TEPPFA report on the environmental footprints of polyethylene pipes.
The lifecycle comparison is an important element of any comparative energy profile. Unlike many traditional pipe materials, plastic pipes do not corrode and offer excellent resistance to a wide range of chemicals. This not only means that they have a longer service life but also ensures the same flow rate throughout their lifespan, guaranteeing that the energy required to pump water through the system does not increase as the pipeline ages. Furthermore, thanks to the exceptionally smooth, non-porous bore of PE pipes they give more flow per metre head/mm bore as compared to ductile iron pipe, ensuring lower pump energy requirements throughout the lifespan of the pipe.
PE pipes have an exceptional 100 year + lifespan and even at the end of their useful service life, they may be collected, recycled and reworked into other polyethylene products.
It is both financially and environmentally viable to recycle PE. Conversely, even if metallic pipes were in a suitable condition for reworking at the end of their much shorter service life, each manufacturing cycle consumes around 300% of the energy needed to rework PE pipe.
Better still, when PE is no longer economically viable for recycling, it still retains significant calorific value - 30% greater than even the highest quality coal – which can be reclaimed as a source of energy.
Read how we help our customers reduce their environmental impact with our PE Waste Collection and Recycling Scheme.
Ideal for Trenchless Installations
The combination of strength and flexibility offered by PE makes PE pipes the number one choice for trenchless installations, which offer significant environmental benefits over open cut methods.
The environmental advantages of a trenchless approach to pipeline installation have been explored in a North American Society for Trenchless Technology (NASTT) study by the University of Waterloo in Ontario. It concluded that on average, trenchless installations produce 90% fewer green house gas emissions than open cut excavations, and can provide overall cost savings of 25–50%.
Greenhouse gas savings are generated mainly by a reduction in traffic disruption, shorter project duration and less usage of heavy construction equipment.
Trenchless installation is also the best way to protect natural environments: not only are plant life and natural habitats undisturbed above ground but root systems below ground are usually unaffected too. The use of horizontal directional drilling (HDD) and microtunnelling on pipeline projects can also preserve fragile ecosystems such as coastal areas and wetlands, avoiding the disruption and damage often associated with excavation.
Securing Water for a Growing Population
By 2025, 1.8 billion people will be living in countries or regions with severe water shortages, while two-thirds of the world's population could be living under water stressed conditions.
Easy to install, with minimal maintenance requirements and a 100+ year lifespan, PE can help address the growing problem of drinking water shortages. PE pipelines can transport water over long distances with virtually no risk of leaks and can also cater for small diameter distribution networks.
Meanwhile, used in computerised irrigation systems, PE pipes can help farmers to avoid wasting vital water, ensuring that food supplies are maintained too. PE drippers mounted in PE pipes can provide tailored irrigation under all topographical conditions to prevent water loss and damage to the irrigation network.
And when fresh water shortages inevitably reach crisis point, PE will be there again to help enable desalinisation technologies and the ''national water super grids” needed for long distance water pipes, securing a hygienic leak-free water distribution network wherever it’s needed.