Measuring the environmental impact of construction projects has become a major concern for water companies over the past couple of years, according to Stuart Crisp, business development director for the Concrete Pipeline Systems Association.
That’s a good thing. But as requests for information on the environmental impact of concrete piping began to increase, Mr Crisp and the CPSA became concerned at the lack of knowledge and consistency in the industry.
“It quickly became apparent that, rather worryingly, the enquirer didn’t know what they were asking for when they contacted us to ask for a carbon footprint,” Mr Crisp says.
“Were they asking for the embedded carbon of the product, the manufacturing emissions or the installed emissions? More often than not, the enquirer hadn’t got a clue.”
This was particularly worrying given that decisions were being made about which products and materials to use based on these enquiries, he says.
“That meant that we were supplying information that was going to be inconsistent.
“That rang alarm bells. There was an endemic situation within the industry. We don’t think the industry is on the same page with understanding what a carbon footprint actually is.”
To address this alarming issue, the association invested in independent research to establish a robust method of working out the environmental impact of different pipe materials.
The CPSA Pipeline Systems Comparison Report, which has been independently verified by carbon consultant Carbon Clear, covers the materials and components of a pipeline system that need to be included in calculations and provides a calculation method that, it is hoped, will provide consistency.
The CPSA says that in being one of the first organisations to do this, it is hoping to establish an industry-wide understanding of carbon accounting processes that can be used to reliably compare different products and activities, and so fairly inform the choice of materials on projects.
It has chosen to use an industry accredited methodology (PAS 2050) to look at a ‘cradle-to-gate’ carbon footprint analysis for precast concrete pipes, manhole rings and cover slabs, which covers the carbon for products from production to the factory gate. Other factors, such as transportation, will affect the carbon footprint from that point on, but this can be calculated too.
The CPSA’s results, including production and transportation processes, conclude that concrete pipes have a CO2e per metre ranging from 17.8 kg for 225 mm diameter pipes up to 592.1 kg for 2100 mm diameter pipes.
The resulting measurements are 20-60 per cent lower than calculations for generic precast concrete based on many existing CO2-only carbon calculators and industry databases.
“The intention of the lifecycle assessment is to provide the baseline data on the manufacture of precast concrete pipeline products and, as a trade association, we have been able to access accurate information from all our members to make sure that our figures are representative of the industry as a whole,” Mr Crisp says.
Taking into account the impact of methane associated with plastic production, installation processes and the type of bedding material needed, the report concludes that concrete pipes have 35 per cent lower embodied carbon than plastic.
Though Mr Crisp admits that calculating carbon footprints is still an “immature science” and no “single, definitive method of calculation has been arrived at”, he hopes this method will be a starting point for much-needed industry standardisation.