Energy

How much energy is consumed in the manufacture of PE pipe?

Environmental Life Cycle Analysis (LCA), also referred to as life cycle inventory or cradle-to-grave study, has been carried out on PE manufactured and used for pipe applications. The Life Cycle Analysis for PE pipe estimates that the total energy consumption from extraction to installation is approximately 95 MJ per kg. of pipe (approx. 26 kWh per kg. of pipe).

Full life cycle analysis, which takes into account not only energy consumption but also effects from emissions etc., indicate that PE pipe has 10 times less environmental impact than the equivalent diameter of ductile iron pipe.

The life from "cradle to grave" of every industrial product has environmental impacts that originate from the extraction of raw materials, processing, distribution, use and finally disposal. The Life Cycle Assessment (LCA) is a method to evaluate these environmental impacts. Emissions that are released into air, soil and water from all the processes including those from energy production, wastewater treatment and disposal are determined and weighted. The purpose of these studies is to understand the total energy consumption and other environmental impact in the manufacture and installation of products.

This method, which is prescribed by ISO 14040 and subsequent international standards, is applied by experienced experts.

Such analysis relies on data not only from the plastics manufacturers (polymer and pipe manufacturers) but also from published data from other associated industries (energy, transport and contractors, etc.). This however may be an overestimation as no account has been made of recent initiatives in recycling.

A critical review and evaluation of nine European LCA concluded that
from an environmental point of view plastic pipe products are of the same level as, and in many aspects preferable to, those made from other materials. This conclusion does not consider all the secondary positive aspects of plastic pipes that are generally not modelled in an LCA such as duration of life, tightness, flexibility, corrosion resistance and light weight.

References

Investigation of European life cycle assessment studies of pipes made of different materials for water supply and sewer systems - a critical comparison. Windsperger, A., Steinlechner, S., Schneider, F.. Institut für Industrielle Ökologie, St.Pölten, Austria. December 1999.

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