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In the third arcle of a series by the Brish Plascs Federaon Pipes Group aimed at aiding specifiers and engineers in considering the environmental benefits of product materials specified for hot and cold water systems, Franz Huelle explains what balancing environmental impacts means. These incorporate a specified set of impact categories covering all stages of a product’s life, from raw material extracon through to final disposal. The numbers are explained using a real example


What are the impact categories?


here are seven categories: depletion of abiotic resources (ADP) which is divided into two, fossil and non-fossil; acidification of soil and water (AD); eutrophication (EP); global warming potential (GWP); ozone depletion potential (ODP); and photochemical ozone creation (POCP). More detail on what they all are and why they are a problem can be found in the full Bulletin at:


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www.bpfpipesgroup.com/sustainability-and- the-circular-economy/overview/


What do the numbers mean?


Numerical assessments of product impacts using the seven categories are presented in a life cycle assessment (LCA) for each stage of the product’s lifecycle. The example shown is from a TEPPFA study of a polybutene pipe system used in a building’s hot and cold water system. Contributions to any one of the environmental impacts will invariably be due to more than one item. For example, common sources of ozone- depleting gases are refrigerants and blowing agents found in insulation foams. But, impact interpretation would be incredibly complex if each gas was reported individually, so a reference substance is chosen – chlorofluorocarbon-ll (CFC-ll) in the case of ozone-depleting gases. The impact of each gas on the breakdown of ozone is


calculated and then converted into the weight of CFC-ll needed to cause the same breakdown. Therefore the total impact of all ozone-depleting gases from the product is reported as the equivalent weight of CFC-ll or ‘kg CFC-ll eq’.


Reference units


The values created by the LCA can assume more or less significance when considering the impact of a product on the environment at a local rather than European level (normalisation), and the relative importance of each category (weighting) to national climate change commitments. So, in the UK, normalisation and weighting factors place a greater emphasis on global warming potential (GWP) and fossil fuel depletion (ADP). ADP – non-fossil: weight of antimony to be extracted to deplete the reserve within the earth’s crust of the resource by the same proportion. Fossil: calorific value of fuel being depleted. AD – weight of sulphur dioxide needed to provide the same acidification (SO2 combines with water to form sulphuric acid) as the acidic gas when it reacts with water in the atmosphere. EP – weight of phosphate needed to cause the growth of algae in water to the same extent as the pollutant (commonly nitrates, ammonia and phosphoric acid).


GWP – weight of carbon dioxide (CO2) needed to have the same effect on trapping heat in the atmosphere as the GHG, typically based over 100 years (GWP100). ODP – weight of chlorofluorocarbon-ll (CFC-ll) needed to break down the same quantity of ozone as the ozone-depleting gas. POCP – weight of the non-methane volatile organic compound ethylene (C2H4) needed to produce the same quantity of ozone as the emitted gas.


By calculating using these categories, an accurate reflection can be made of a product’s entire life cycle impact, which will help guide design engineers towards products with lower overall impacts in future construction projects.


Next bulletin: Learn about how to illustrate an LCA in the form of an Environmental Product Declaration using examples of hot and cold water supply inside buildings.


Franz Huelle is Chair of the BPF Pipes Group’s drafting panel and is also head of technical, building solutions – UK and Nordics – at Rehau UK.


INDUSTRY COMMENT: BPF Evaluating the environmental impacts of product


choice for hot and cold water supply in buildings BULLETIN 3: BALANCING ENVIRONMENTAL IMPACTS


22 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JANUARY 2020


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