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Left: A district heating illustration
Right: Plastic pipes are used in underfloor heating
Pipes & fittings
include raw materials, transport, distribution, employee travel and waste disposal. In plastic pipes manufacturing, the largest amount of emissions typically falls under scope 3.
Whilst manufacturers can to some extent control emissions under scopes 1 and 2 – such as by moving away from fossil fuels in replacing forklifts and company vehicles with electric versions, going to a 100% renewable energy provider for electricity and reducing resource waste (such as reusing factory heat) – scope 3 is harder to improve as much of it comes from raw material extraction and logistics. Examples to reduce these emissions include using recycled plastic and optimising transportation of pipes where possible. Current legislation and availability from raw material suppliers only allows recycled plastic pipes to be used in some non-pressure applications like cable ducting, twinwall drainage and land drainage/irrigation. Due to strict quality and safety standards, areas like drinking water (both inside and outside the building) and gas pipes require 100% virgin material to ensure the highest possible safety for end users and operators. Another topic to consider is the difference in
carbon emissions from transporting plastic pipes versus traditional pipe materials. For example, a 100km journey with a full load of 225mm plastic
pipes results in four times lower carbon emissions than the same for the equivalent size and quantity of clay pipes and five times less than for concrete pipes – 23kgCO2e compared with 98kgCO2e and 123kgCO2e respectively.
Applications of plastic pipes
Efforts to decarbonise heating by 2050 will likely involve a combination of hydrogen, heat pumps and the wider use of district heating networks. One of the main drives of this will be the phase-out of gas boilers from all new build homes from 2025. At this stage it is hard to predict what the mix will look like in the future. Currently heat pumps and district heating are already being installed widely across the UK, whereas hydrogen for home heating is still in the early trial phase. The Government announced in the Heat and Buildings Strategy that a decision on its wider use in heating buildings will be made by 2026.
As 90% of the UK gas network is already using
polyethylene (PE) pipes, these can continue to be used for hydrogen which cannot be transported via older metal pipes. Hydrogen has some technological challenges to address as it’s not a simple replacement of the gas in the network. It’s also unclear at this stage what the possible costs to the end user could be which is a key topic for its wider deployment. Early stage trials have already begun in the UK introducing small amounts of hydrogen into the gas network linked with hydrogen-ready boilers, which will be closely monitored.
Heat pumps are expected to play a major role in our Net Zero push with the Government target of 600,000 heat pumps installed annually by 2028. In
ground source heat pumps, PE 100 pipes are used to extract heat from the ground in vertical boreholes up to 150m deep, and for horizontal systems coils of pipe are laid in loops buried 0.8-1 m deep. In air source heat pumps located away from the building, pre-insulated plastic pipes are ideal to transfer heat back to the building. District heating, where heat is produced centrally
and transported via an underground insulated pipe network, is another area where the Government is investing significantly. Possible heat sources include a wide range of fossil and renewable sources but the main low carbon options for new schemes are heat pumps and waste heat. The UK aims to grow district heating from 3% to 18% of total heat demand by 2050 and plastic pipes will play an increasingly major role as they have high corrosion resistance, provide faster installation (no welding), come in long flexible coils and require no expansion bends, unlike traditional steel pipes. Other energy-efficient technologies where plastic
pipes are used exclusively include underfloor heating, which is more efficient than radiators and commonly used on heat pump projects, and for the growing ducting requirement in EV charging points as well as for HVAC pipework at wind farms. According to its Environmental Product Declaration plastic plumbing pipework has a three times lower global warming potential than traditional copper and a four times lower ozone depletion potential too, even where the copper is 80% recycled. In general, plastic pipes used in construction should not be viewed in the same vein as single use packaging as their lifetimes in effective use are increasingly over 50 (in some cases over 100) years. Pipe manufacturers are starting their own Net Zero journeys and implementing measures to reduce their carbon footprints even further which will in turn help those developing and constructing homes, offices and commercial and industrial buildings. Plastic pipes therefore have a vital role to play in the new low-carbon technologies due to their inherently good thermal, chemical and mechanical characteristics.
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