Through its production of plastic pipe systems worldwide, Aliaxis is making its contribution to a better future for the people of this planet. Research studies show that PVC and PE pipes are better and more environmentally-friendly alternatives to pipes made from other materials like concrete or iron, and our society is reaping the benefits.
Life Cycle Assessments (LCAs) of PE and PVC have been conducted to assess the environmental impacts associated with all stages of their product life: from raw material extraction through materials processing, manufacture and distribution to final use, repair, maintenance, and disposal or recycling. In 2017, for example, the Life Cycle Assessment of PVC Water and Sewer Pipe and Comparative Sustainability Analysis of Pipe Materials was published. This was the first comprehensive environmental review of underground piping systems in North America. The results of this study show that PVC pipes provide both environmental and economic advantages for water and sewer infrastructure for utilities and municipal projects.
Research studies show that PVC and PE pipes are better and more environmentally-friendly alternatives to pipes made from other materials like concrete or iron.
Studies such as these on PVC or PE prove that plastic pipe systems have fundamental advantages in terms of creating sustainable piping for water and sewage infrastructure: it is recyclable and reusable, durable and long-lasting and resistant to corrosion. It is estimated that PVC and PE pipes can have a lifetime exceeding 100 years.
Resistance to corrosion
Corrosion is one of the biggest problems associated with metal piping systems. It occurs both inside and outside the pipe and affects hydraulic efficiency. Many cities are treating their water in efforts to slow down rusting and pitting. Others choose expensive alternatives like cathodic protection, plastic coating or sleeving, with the aim of extending the pipes’ service life but without being able to avoid increased production and maintenance costs.
Unlike many traditional pipe materials, plastic pipes do not corrode and offer excellent resistance to most types of chemicals. They can resist most strong acids, alkalis and aqueous solutions, as well as brine, mineral oils, fats and alcohols. This means that harmful chemicals are highly unlikely to infiltrate water supplies. The resistance of plastic pipes to corrosion also ensures a consistent water flow rate throughout their lifespan, guaranteeing that the energy required to pump water through the system will not increase as the pipeline ages.
From an engineer’s viewpoint, plastic pipes entail lower installation and maintenance costs. For piping infrastructure, plastic is already the material of choice for many municipalities in Canada and the UK, for example.
The manufacture of PVC and PE pipes requires less energy than the production of steel, copper, ductile iron or aluminum pipes. By contrast, energy-intensive zinc applications are required for the essential galvanization steel and ductile iron pipes. An additional energy-intensive cement lining is often inserted into ductile iron pipes to increase their resistance to corrosion.
Plastic pipes also save energy, thanks to the lower energy requirements for their transport, handling, installation and maintenance. For example, PVC and PE pipes are eight times less dense than steel pipes, therefore there is no need to bring in heavy lifting equipment to shift them while they are being installed.
Smaller risk of leakage
Globally, up to 30% of all piped water is lost through pipe leakages somewhere in a system. The main cause of this is pipe failure. Plastic pipes, whether PVC or PE, are flexible and do not carry the same inherent risk of cracking as metal o or concrete alternatives. They are less affected by ground movements and are strong enough to withstand deformation from traffic loading. Their inherent resistance to corrosion also makes them less vulnerable to leaks originating inside the pipe.
Plastic pipes also require fewer joints than those made from concrete, iron or metal. PE pipes, for example, can be produced, transported and installed in longer lengths than metal pipes. This allows plastic pipelines tube installed with up to two or three times fewer joints than pipelines made of traditional materials. Moreover, as lengths of PE pipes are fitted together with fusion-jointing processes, they are less liable to leak.
Plastic pipe systems can also be installed with so-called ‘trenchless technology’, creating far less disturbance to traffic flows and the environment than the traditional systems they are often replacing.
The installation of traditional piping systems usually starts with a trench being dug in the road, resulting in major traffic and environmental disruption. For trenchless installations, on the other hand, a continuous borehole is drilled beneath the ground by a horizontal directional drilling machine. Once the drilling head reaches the end of the borehole, the plastic pipe is attached to it and pulled back through the hole.
The flexibility of plastic pipes, combined with their tensile strength and resistance to abrasion, makes them a perfect fit for this trenchless installation technology.
At the end of their service life of sometimes 100 years or more, plastic pipes can be collected, recycled and reworked into other PVC or PE products. It is possible to recycle and reuse them at any stage in their life-cycle, whether early during the manufacturing or much later at a post-industrial use stage.
PVC, for example, is recycled either mechanically through being ground into tiny particles which are then converted by heat into a plastic material for factory use, or chemically through being reduced by chemical or heating processes to its molecular components before being fed either into the manufacture of new PVC or used as fuel for energy recovery. This reusability effectively cuts down waste material from the production line and reduces the overall burden of disposing of PVC piping. It also limits PVC’s environmental footprint over time.
A word from an expert
“Our company EPCOR, which is based in Edmonton, is a private utility company that focuses on water, waste water, electrical distribution and natural gas distribution. When I started working for this company, the water distribution network in Edmonton experienced up to 10,000 pipe breaks a year, detected primarily in cast-iron distribution pipes. This led the city to consider an alternative pipe material, namely PVC.”
“The primary benefit of PVC pipes is their reliability” – Doug Sergeant, Senior Manager, Distribution Infrastructure, EPCOR Water Services Inc.”
“The primary benefit of this material is its reliability. We find that we need not devote much effort to maintaining these pipelines and operating them in the long term. We also find that it’s an easy material to work with. It is lightweight, very easily field-adaptable and we have cost-effective installations when we are using PVC. In the long term, the costs of maintaining our water distribution network are going down and the number of water main breaks that we have to repair each year is also going down.”
“From an environmental perspective, Edmonton’s water distribution network now experiences very little leakage. We use the international leakage index, and the leakage number that we have recorded for Edmonton over the past 5 years has been less than 1.5, which puts us at the level of a World Class System. Finally, from an end-customer’s perspective, we have noticed that in the systems where PVC is used, the quality of the water is great.”