Thermoplastic pipes can be fully recycled into new pipes
Our industry is also recycling post-consumer waste where pipe is collected from the waste stream and recycled back into new pipe products. The amount of waste that can be consumed by the manufacturer of new pipe is currently limited by the very low volume of plastic pipes in the waste stream. This recycled material is incorporated with virgin materials at varying levels to manufacture new pipe, having the same life and performance expectations as pipe made from solely virgin materials.
The ability of Sandwich Construction (SC) PVC-U to use manufacturers own rework, post-industrial and post-consumer PVC waste in the sandwich core layer is directly responsible for the successful diversion of useful PVC from landfill in Australia.
Some types of plastic pipes are produced using recycled plastics from other applications, contributing even further to the circular economy
One of the great things about plastic pipe design is that while in some cases using post-consumer sourced recyclate is not permitted in the Australian pipe standards (for good reasons like potential effect of contaminants on drinking water, or potential effect on the ability of the pipe to meet the necessary strength requirements) – there are many pipe options that can readily accommodate post-consumer recyclate. Products such as multilayer PVC drainage and conduit or PE drainage pipe already use post-consumer recyclate as feedstock.
When the use of post-consumer recyclate is permitted, the pipes are still required to meet all requirements of the relevant Australian Standards – so performance is assured.
Waste generated when a product is being installed (i.e. offcuts) and product at the end of its useful life (this includes other products than just pipe).
Manufacturing scrap generated during manufacture is reground and fed back into their manufacturing process.
To assist with diverting waste to landfill manufactures will also externally source post-industrial waste from other sources and use this in their manufacturing processes.
The recycling rates for plastic pipes are very low because pipes have a very long service life and very little product has reached end of life.
This was confirmed by the NSW Government audit of Construction and Demolition waste. In one landfill site of 600,000 tonnes of C&D waste less there was somewhere between 1,000-3,000 tonnes of plastic pipe waste- that’s 0.1-0.5%! The reason why is due to their durability and very long service life, typically more than 100 years – making them the perfect choice for building and infrastructure materials. Today, plastic pipes are still in their first life cycle.
Due to the low volume of plastic pipes in the waste streams, our industry is always looking at ways to work collaboratively with waste management companies, major distributors of products and specific suppliers/clients to collect volumes of plastic pipes viable for designated recycling. – find out more about PIPA’s recycling program and partners.
PIPA’s PVC pipe and fittings manufactures and resin suppliers are signatories to the Vinyl Council of Australia (VCA) PVC Stewardship Program.
This program centers on 5 key themes associated with the lifecycle of PVC, with specific commitment and targets to be met.
In 2005 PIPA was part of a 3-month pilot conducted in Sydney on the collection and recycling of plastic pipes in the demolition and construction waste stream. The four recycling centres in Sydney processed approx. 8000 tonnes of waste per week. The trail demonstrated:
The manufacturing process reuses scrap to make other pipes.
Fundamentally, plastic material is in the form of either powder or small pellets that is fed at a controlled rate into a heated barrel and pushed through by a screw. Electrical heating elements provide heat and the material progressively increased in temperature to between 160-200°C. At these temperatures, the thermoplastic material melts and can be formed into shape. There are two processes typically used – extrusion and injection moulding.
In the extrusion process the melted material is continuously forced through a die which forms the round shape required. As the material exists the die its immediately cooled, freezing in the required shape and size. After the formed pipe is cooled, it is cut to length.
In this process for the manufacture of fittings, the material is injected into a closed mould of the required shape. The product is then cooled in the mould. Once cooled and the shape frozen, the product is ejected from the mould.
Production plants are clean and efficient with low emissions.
The main inputs are the plastic pellets or powder and electricity. Production equipment is electrically powered and heating is electric as the temperatures required to melt the plastic are relatively low. This results in a very clean enclosed process. There is no combustion or chemical reaction required and therefore no smoke or emissions are produced.
Australian Standards for PVC pipe specifically exclude heavy metal (e.g. lead and cadmium additives (PIPA, 2014), as the only national PVC pipe product standards to do so worldwide.
The Adaptation of the USGBC TSAC Report for Relevance to Australian DWV Pipe (BRANZ, 2008) found that for typical pipe products “No single material shows up as the best across all the human health and environmental impact categories, nor the worst”.
The GBCA further found that the level of dioxins emitted due to best practice production of PVC and its constituents is much less than that from other sources. Therefore, there is insufficient rationale for discrimination against PVC building products on the basis of dioxin emissions (GBCA, 2010).
The manufacturing process for plastic pipes has a low carbon footprint. They are clean, low emissions and lower embodied energy.
In the case of PVC pipes, the dominant impacts are from electricity use to extrude the pipe which can be addressed with renewable sources. When cast iron pipe was manufactured in Australia it had only 15-20% recycled content and was principally produced from primary sources using blast furnace. All cast iron pipe is now imported into Australia and has not been transparently assessed in an LCA. Furthermore, the impacts of transport costs need to be factored into any LCA for cast iron pipe in Australia.
Studies done in Europe comparing the energy consumption and CO2 emissions of oriented and conventional PVC, PE, concrete and ductile pipes found Oriented PVC to be the best performer, followed by conventional PVC and PE pipe with ductile iron being the most unfavourable case with an energy consumption 56% higher and CO2 emission 51% higher than conventional PVC.
Studies done by the CSIRO in 2002 comparing a range PVC, PE and Ductile Iron pipes of differing sizes and operating conditions found that Oriented PVC systems have the lowest embodied energy and Ductile iron systems the highest. Depending on pipe size and operating conditions the PVCO systems performed over 6 times better than DICL.
Plastic pipes have performed very well in full life cycle assessments, demonstrating high sustainability standards across the life of the product.
Based on numerous LCA studies, plastic pipes have a significantly better environmental profile than cast iron and copper pipes against all categories and across their whole lifecycle.
Plastic pipes have lower ecopoints than other materials. Lower ecopoints signifies better environmental impact.
Low cost is a result of lower energy input in production, transport and installation. Lower energy means lower CO2 emissions to the atmosphere and reduced consumption of resources such as coal, oil and gas to produce energy.
Durability and long life mean that pipes do not need to be replaced or repaired as frequently compared to other materials as they don’t corrode and are recyclable.
This often relates to lower energy in operation or better protection systems for applications such as communications conduits.
Asbestos cement pipes for example were commonly used for drinking water supply but this material is now not acceptable at all. Asbestos cement pipes can crack due to soil movement over time leaving a very difficult problem to repair due to the health risks associated with asbestos fibres.
Lead pipes were used for household plumbing, but this material would not be acceptable either.
Clay pipes used for sewer systems leaked and cracked over time so their performance would no longer be considered acceptable. They were often damaged during installation and poor joints often resulted in cracking and leakage. Blockages due to roots penetrating these lines were common often resulting in expensive repairs.
This generally leaves us with iron and steel or copper. Both expensive by comparison and have higher embodied energy. Whilst Iron and steel pipes are strong, they are heavy and more expensive to install. Both have corrosion issues that affect life. The failure of old corroded iron pipes resulting in substantial lost water, flooded roadways and property are still common. The cost of copper is increasing due to factors such as increasing demand for applications such as cabling, electronics and electric vehicles.