McKinsey has concluded in its July 2022 report that plastics have a lower total greenhouse gas (GHG) contribution than other pipe materials.
Based on GHG assessments from 2020 conditions in the United States, applications of plastic to alternatives were compared in five industries where plastic is extensively applied: building and construction, automotive, textiles, packaging and consumer durables.
The beneficial uses of plastic are generally disregarded due to its negative reputation in the environmental sphere; however, it plays a crucial part in improving use efficiency. Plastic pipes are becoming progressively ubiquitous as durable engineered solutions in many installations.
Life-cycle analysis was included in the discussion of plastic sustainability along with an evaluation of the overall direct and indirect GHG emissions of plastic and substitute materials.
Among the building and construction sector, plastic materials used for sewer and residential water pipes were compared to their next best alternatives.
Regarding sewer pipes, the report notes that PVC and reinforced concrete are the most widely used materials for gravity pipes, whilst PVC and ductile iron are the most widely used materials for force main or pressure pipes.
It was concluded that PVC has fewer GHG emissions, with levels that are roughly 45 per cent lower than reinforced concrete and 35 per cent lower than ductile iron, based on the premise that all four pipes have a fixed service life of 100 years.
The report includes cross-linked polyethene (PEX) and copper type L pipes as two typical examples of residential water pipes. Since copper has a higher thermal conductivity than plastic, its GHG emissions from incremental heat loss are higher than PEX.
Due to its heavier weight and more energy-intensive manufacturing process, copper pipes also produce emissions that are around 2.5 times more than those of PEX pipes. When compared to copper pipes, PEX pipe has approximately 25 per cent lower overall GHG emissions.
The advantages of plastics do not lessen the need for the industry to keep enhancing sustainability practices, though.
“GHG footprints for all materials will be improved by a cleaner energy mix, improved recycling rates, and higher commercial BEV penetration rates,” the report states. “Each material has the potential to have the lowest GHG emissions under the right set of conditions.”
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