Sustainable plastics
There are many ways in which plastic pipework system contribute to the environmental credibility of a building, as Des Dolan of Durapipe Building Services explains.
Sustainability has become an imperative consideration in the design and construction of new-build and refurbishment projects across all sectors. Every architect, consultant and contractor needs to be able to demonstrate the environmental impact of their proposals to ensure they can continue to compete for new projects.
In the UK there are two main recognised assessment frameworks that evaluate environmental impact of new developments and refurbishments. They are BREEAM for non-domestic buildings and the Code for Sustainable Homes for residential properties.
Setting the standard for best practice in sustainable building design, construction and operation, BREEAM includes the measurement of the performance of a range of building materials and systems against specific environmental impacts. As a result, specifiers and consultants should be considering the sustainability credentials of all the systems that they specify for any building project — and pipework is no exception.
There has always been a ongoing debate comparing plastic pipework systems with metal alternatives, with arguments for and against both options when it comes to installation and performance. When it comes to sustainability there is a perception that plastics are not the most environmentally friendly material. However, looking at the environmental impacts of pipework systems, the benefits of selecting a plastic system are clear to see.
There are a lot of negative perceptions about the production of plastics using dwindling oil reserves. However, plastics only use 4% of the world’s oil as feedstock, compared with the 87% that is used for transport, energy and heating simply being burnt and lost. Plastics represent the most sustainable use of oil, as they only ‘borrow’ energy during their lifetime, and this can be recovered in the form of heat, which can be converted into electricity.
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| Plastics pipes in building at the Abraham Darby Academy include Durapipe’s Friaphon for waste-water drainage. Push-fit connections reduce installation time, and its acoustic properties mean there is no need for lagging. |
Because lower conversion temperatures are required, less energy is used in the manufacturing of plastic pipe and fittings from raw material, compared with steel pipe. On average 10 GJ of energy are required to manufacture plastic pipework systems, compared with 25 GJ for copper and 29 GJ for steel.
Scrap produced during the manufacture of plastic can be recycled and reused. There are two primary methods for recycling plastics — mechanical recycling and feedstock recycling. Mechanical recycling is the simplest method, which is where plastic is heated and reformed into moulding granules to make new products. Feedstock recycling involves breaking down polymers into their constituent parts through the use of heat or pressure; in turn, these parts can be used to produce new plastics and chemicals.
Used plastics can be recycled up to six times, but when it is no longer economic to recycle them, it is then possible to recover the thermal content through energy from waste incineration (EfW), providing an alternative source of energy. The UK currently has 24 EfW plants, with plans for more to be built over the coming years.
There are further savings to be made during the installation process. Typically, plastic pipework is a sixth of the weight of a steel alternative, and their light weight makes plastics much quicker and easier to handle on-site, eradicating the need for expensive lifting equipment.
The lightweight nature of plastic pipework systems also offers benefits during the transportation of products, as plastic pipework can be transported in greater volumes, meaning fewer deliveries are required. Fewer deliveries provides the obvious environmental benefits of using less fuel for transportation than traditional materials.
An installed plastic pipework system will also continue to provide energy savings over its lifetime. All plastic materials have low thermal conductivity, resulting in less heat being lost through the pipe wall, reducing or, even, eliminating the need for further insulation.
The smooth bore of plastic pipework systems ensures no corrosion or limescale build up, so flow will not become restricted, ensuring the same flow rate throughout the system’s lifetime and guaranteeing that the energy required to pump substances through the system does not increase as the pipework ages.
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| From manufacture to use, plastic pipework systems uses less energy and are associated with lower carbon emissions than metals. |
Furthermore, the smooth inner pipe walls mean plastic materials have less turbulence, lower velocities and less friction loss than traditional pipework materials. This means less energy is required to move fluids throughout a system and that a lower pump output is needed.
At every stage of its lifecycle, a plastic pipework system reduces the level of energy consumption, compared with metal pipe systems. On a typical commercial building project, the real impact of using plastic pipe and fittings equates to about 2314 kg CO2 saving compared with copper and a 3606 kg CO2 saving compared with carbon steel.
Plastic pipework systems are a sustainable and environmentally responsible choice, demonstrating that they are energy efficient during manufacture and provide peak performance during service. Strong, durable, lightweight and flexible, plastic pipework systems require significantly less energy to manufacture, transport and install than metal alternatives and supply a long service life.
Contractors, consultants and specifiers need to be carefully considering the environmental impact of pipework systems, along with all other building materials, at the outset of a project to ensure the overall proposal offers a sustainable solution that ensures they can compete effectively for new projects.
Des Dolan is brand manager for Durapipe Building Services.
